World free HIV: the novel therapeutic approaches for eliminating latent HIV infection

Abstract

Antiretroviral therapy (ART) is an intervention aimed at preventing the development and spread of HIV. The persistence of proviruses in the CD4 + memory T cells, which are transcriptionally inactive and other drug-resistant reservoirs, makes treatment of chronic HIV-1 infection through pharmacological means complex. The major measures to deal with the disease involve reactivating the inactive viruses then clearing them off by using virus-specific cytotoxic effect and also by host immune responses. Broadcast screening and mechanism-based techniques have revealed a huge number of medications that can reactivate latent infections. The review carried out relies on Cochrane Central Register of Controlled Trials (CENTRAL), PubMed (NCBI), Scopus (Elsevier), and Web of Science (Clarivate) databases. Some of the therapeutic alternatives mentioned are Shock and Kill, cytokines, chemokines, histone methyl transferase inhibitor, immunotherapy, protein kinase C activator, P-TEFb activator, and uncharacterized ones like vorinostat and disulfiram. These techniques have proven to be effective using models working with CD4 + T lymphocytes and dormant cell lines in HIV-1 infected patients. The given paper includes an in-depth evaluation of the existing situation in the field and its hardships.

Introduction

Passively contaminated cells are also referred to as those that have incorporated the DNA of HIV but are not under transcriptional activity at the moment. These cells however, can generate infectious viruses when they are activated. Although it is logical to expect that in a case of latent infection, cells will neither produce HIV RNA nor proteins, a large body of evidence negates this implication. It has been demonstrated that patients receiving antiretroviral therapy have lower the HIV RNA content in the resting CD4 + T lymphocytes [1–4]. Additionally, after receiving ART, the individuals’ peripheral blood mononuclear cells (PBMCs) have lower quantities of HIV RNA [5]. Compared to active CD4 + T lymphocytes, HIV-infected resting CD4 + T cells have decreased RNA levels [6]. Doubt has always existed on whether these levels are enough to produce large amounts of protein. The qualitative difference between quiescent and active CD4 + T cells is based on the production of HIV transcripts between these cells. In large amounts, abortive transcripts are identified but in non-activated naive CD4 + T cells, pre-mRNA is prevalent, and spliced forms are less common than the former [7, 8].

The HIV RNA found in naive CD4 + T cells may reflect cells that have recently been activated but have not yet elevated activation markers, in addition to the potential that it comes from cells that have recently transitioned from an activated state [9]. This does not indicate that HIV RNA transcription occurs in cells with latent infection. There may be a latency spectrum that includes cells that are not transcribing the RNA of HIV despite being secretly infected, as well as cells that are producing HIV proteins but are unable to generate infectious viruses. Various subsets of inactive infected cells might encounter different hurdles on their way to effective infection. In case, the latest models, i.e., the direct injection into resting CD4 + cells, have shown a decrease in p24 production [10, 11]. Therefore, it is crucial to assess the HIV protein production capacity of cells with latent infection, as this could indicate that these cells are potential targets for inducing strong immune responses or effective cytotoxic T lymphocyte activity [12].

Shock and kill strategy therapy

“Shock and Kill” is a terminology that is used to refer to a strategy of eliminating HIV reservoirs with the help of latency-reversing agents (LRA) [13–15]. There are several steps involved in this process. In the first, latently infected cells are exposed to a latency inverting agent, which causes the infected cells to become active. Therefore, these cells initiate the production of the RNA of HIV, proteins and the viral particles. Finally, the immunological effectors such as cytotoxic T lymphocytes and cytopathic damage resulting due to the virus destroy these cells. However, a number of challenges still persist in the bid to eradicate HIV reservoir in the human body and restore HIV latency in human body using (LRAs). Many treatments have been tested in clinical trials as latency-reversing agents; however, the great majority have shown minimal effect on the reduction of the organism’s reservoir of latent cells infected with HIV [16–19]. This implies that the functions of the LRAs are not as expected. Since the mechanisms that control HIV latency in vivo are highly complex, our results confirm that in vitro efficacy of LRAs may not be a reliable predictor of their in vivo efficacy [15, 20, 21]. Recent studies have indicated that reactivation of stimulation is not effective on a considerable number of T cell reservoir cells, even though proviruses can be found within a range of such cells that can be replicated [22]. Moreover, HIV treatment naive persons who undergo treatment with LRAs alone might even encourage the production of infectious viruses in reactivated, persistently infected cells to the ultimate result of infecting normal bystander cells. Thus, LRAs must be used with efficient combined antiretroviral therapy cART to maximize the LRA treatment to eradicate the HIV reservoirs. Studies have demonstrated that a significant percentage of T lymphocyte memory cells carrying replication-competent proviruses do not undergo stimulation-induced reactivation [22]. Also, HIV treatment-naive persons receiving LRA only can lead to the generation of infectious virus by reawakened latent infected cells, thus causing infection of normal bystander cells. Therefore, integrating LRAs and effective cART is needed to maximize treatment to destroy HIV reservoirs. A number of small-molecule drugs, especially those that are used in the early phases, have been developed or discovered as Lag-reversing agents. These include histone deacetylase (HDAC), protein kinase C (PKC), and bromodomain-containing protein 4 (BRD4). inhibitors: JQ1, SAHA (vorinostat), prostratin, and bryostatin-1 [23, 24]. Oncological treatments were used, and an investigation of LRAs with (HDAC) inhibitors, including vorinostat and valproic acid commenced with them. This notwithstanding, there was no significant decrease in HIV reservoir cells. Nevertheless, the other clinical trials that investigated the HDAC inhibitors were showing that there was the rise in the amount of HIV RNA in cells and plasma after latency reversal. Vorinostat and other HDAC inhibitors should be used with caution since they can increase CD4 + T cell depletion tolerance to infection with HIV [25].

Along with the latency-reversing agents are such drugs as PKC agonists or activators. The compounds are important in regulating cell division, proliferation, differentiation and apoptosis [26]. By attaching to the HIV long-term repeat (LTR), PKC activators/agonists affect transcription factors such as nuclear factor kappa B (NF-κB), which is necessary to start transcription of the HIV messenger RNA [64]. PKC activators, such as PEP005 have been shown in vitro to have serious latency-reversing effects in in vitro models using several HIV cell lines that are dormant and the patient’s original virus-infected cells [27–29]. The recent clinical trial showed that bryostatin-1 is a PKC agonist safe when used as a single-dose. However, the drug’s inability to induce dormant HIV transcription in vivo was likely influenced by the low pharmacokinetic concentrations [16]. It has been observed that the PKC activators including PEP005 have a great potential when used together with LRAs belonging to other classes. Many research groups believe that the best approach to enhance LRA reactivation is combination therapy because it is demonstrated in Fig. 1 [27].

Fig. 1.

Theoretical presentation of the shock and kill method of the cure of HIV. In case of Anti-retroviral Therapy (ART), HIV integrated DNA remains in the latent form in the genome of host and in the resting CD4 + T cells. Latency-reversing agents (LRAs) cause the HIV virus to express proviruses during its latency, which produces HIV RNA, viral protein and virus-producing activities. The re-infected cells can then be removed either by immune-mediated removal (e.g., cytotoxic T lymphocytes or antibodies) and/or by cytopathic activities caused by the virus. The final aim is selective killing of the infected cells and thus reduced latent HIV reservoir

The high degree of localization of transcription factors that significantly increase the activity of the 5-LTR promoter is another important aspect of the integrated proviruses’ epigenetic environment. According to research findings, integrated proviruses have genetic and epigenetic properties which affect the susceptibility of the infected persons, who suffer latently, to LRA. Thus, it might be crucial to add the much-vastly acting LRAs (e.g. PKC activators or HDAC inhibitors) into the row of methods and modalities, which address various pathways, to accomplish assured clearance of HIV reservoirs in vivo. This is especially pertinent considering that it was found that disparate pharmacological responsiveness of the various HIV-infected cells to the LRAs; like, Battivelli et al. [30]. A portion of cells with latent proviruses could only be reactivated by LRAs, according to their in vitro model testing results. To eliminate cells which can form HIV, it is important to use pharmacological agents having varied mechanisms of action or effective therapeutic combinations. Three main approaches have been applied to conduction of preclinical trials in the cure of HIV; the primary cell system maintained in controlled laboratory settings, preclinical animal model and other tests conducted in vivo on clinical specimens. The success is assumed when these models are able to mimic the drug effects in vivo. Activation of a HIV provirus to viral production or entering latency mostly depends on its genetic and epigenetic environment [31]. Because they only have one or two proviruses integrated into particular genomic loci of the host genome, cell-based HIV latency models like ACH2, U1, and J1.1 cells may only replicate a small subset of the broad integration sites seen in vivo. Even with clinical samples from HIV-positive people, ex vivo models may not capture all viral integration sites. A significant challenge in conducting reliable and scalable studies on pharmaceutical effects is the low frequency of cells that are infected with HIV, especially in the blood from the peripheral of people with HIV who are on cART [22, 32]. While animal models are effective for data collection in preclinical testing, the required resources and costs make them impractical for large-scale screening. As a result, compared to conventional in vitro models, a novel in vitro infection model utilizing Jurkat cells has recently been created. This form of infection contains a much wider variety of HIV-infected cell clones. The antiviral activity of cART, drugs, and their impact on the clearance of LRA-driven reservoirs can all be investigated concurrently with this model. Table 1 summarizes various studies related to the activation of latent HIV reservoirs [35].

Table 1.

Represents the different studies on the reactivation of the virus in the dormant phase and elimination by the immune system

	Drug	Number of patients	Design	Results
Lehrman et al., 2005 [33]		4	Assessment of pathogenic units per million cells	Decreased viral reservoir after valproate administration
Siliciano et al., 2007 [34]		9	A longitudinal study intended for people receiving valproate and antiretroviral medication together	No changes were observed
Sagot-Lerolle et al., 2008 [35]	Valproic acid	11/13	Case study	No effect
Archin et al.,40 2010		3	Inspections of Lehrman et al. 37 at 48 and 96 weeks.	No enduring effects of valproate in first responders
Routy et al., 2012 [36]		56	Randomized trial (27 participants given valproate during weeks 0–16, 29 participants administered valproate during weeks 16–32)	Lethal units per billion cells were unchanged at 16 or 48 weeks.
NCT01319383 (2011-02- 2016-03-31) https://clinicaltrials.gov/study/NCT01319383	Vorinostat	30	Single dosage of 400 mg	Elevation of cell-associated HIV RNA in quiescent CD4 T cells
NCT01365065 (2011-05- 2018-01). https://clinicaltrials.gov/study/NCT01365065		20	400 mg every day for 14 days; first follow-up at 24 weeks	NA
NCT01680094 2012-09- 2014-01 https://clinicaltrials.gov/study/NCT01680094	Panobinostat	16	20 mg	NA
NCT01286259 2011-01- 2014-05 https://clinicaltrials.gov/study/NCT01286259	Disulfiram	20	Daily 500 mg for one month	NA

Stimulators of transcription factors

After T cell receptor (TCR) activation, protein kinase C (PKC), a member of the serine/threonine kinase family, mediates a number of cytoplasmic effects. The nine different PKC isoforms are divided into three main groups: PKCα, PKCβ, and PKCγ make up the conventional group; PKCδ, PKCε, PKCη, and PKCθ make up the novel group; and PKCζ and PKC₄ make up the less well-known atypical group [37]. Activation of classical conventional PKCs requires calcium and diacylglycerol [38], whereas atypical and novel PKCs function independently of these requirements [39]. After TCR activation, membrane-associated phosphatidylinositol 4,5-bisphosphate is converted to inositol 1,4,5-trisphosphate (IP3) by the enzyme phospholipase C gamma (PLCγ) [40]. The subsequent release of inositol trisphosphate (IP3) into the cytoplasm triggers the mitochondria to release calcium ions, which are then incorporated into diacylglycerol (DAG), remaining firmly attached to the membrane. DAG PKC activation is enhanced majorly through allosteric mechanisms. Additionally, IP3 is an additional PKC allosteric activator that facilitates Ca2 + discharge. Downstream signaling cascades are triggered when all LRAs that activate PKC, including DAG, connect to the DAG-binding pocket. These LRAs, therefore, have the capacity to activate PKCs, either having or lacking recognition.

PKCs are important in inactivation of the inhibitor of kappa B (IKB) so that the translocation of NF-ka can take place into the nucleus which is followed by the activation of the NF-ka promoters like the HIV (LTR) [41]. PKC agonists can be classified into three classes based on their chemical structure: phorbol esters (such as prostratin, DPP, and PMA), macrocyclic lactones (such as bryostatin-1 and its analogues), and diterpenes (such as gingenol and its analogues). Phorbol esters, particularly PMA and prostratin, have been found to have the ability to reactivate HIV-1 transcription, according to the literature. Clinically dormant or latent HIV-1 can be effectively eliminated by applying the calcium ionophore ionomycin, which raises intracellular Ca2 + concentration, to ex vivo primary CD4 + T lymphocytes isolated from HIV-1-infected individuals and in vitro cell models, according to numerous studies [42].

Although prostratin and DPP have been shown to be able to reverse retardation in cells generated from patients with HIV ex vivo, they also do not cause carcinogenesis [43, 44] and to trigger HIV-1 proviral gene transcription in a variety of in-vitro models [45]. Clinical trials involving prostratin and DPP were halted due to toxicity concerns. The combination of prednisone [46] and ionomycin serves several purposes in in-vitro HIV reservoir studies and is arguably the most potent biochemical agent for reversing latency and activating T cells. In contrast to phorbol 12-myristate 13-acetate (PMA), the potential anticancer characteristics of bryostatin-1, a macrocyclic lactone and PKC agonist, have been investigated in numerous clinical studies [46]. A bryostatin-1 does not promote cancer. It is not very effective at revitalizing HIV-1 in vitro, especially in Jurkat-LAT-GFP cells. It is only in a single clinical trial done to determine its efficacy and safety in eradicating HIV-1. This study has demonstrated that neither latent HIV-1 transcription nor PKC activity were significantly impacted by bryostatin-1.

Much attention has been paid to ingenol-B and ingenol-3-angelate, two diterpene compounds by researchers. Ingenol-3-angelate has two main purposes: a topical agent used in treating actinic keratosis and efficient agent in reversing the latent HIV 1 infection in in-vitro and ex-vivo biological systems. According to [47], transcription initiation, transcription elongation and total levels of transcription increase in HIV-1 transcription of skin biopsies of patients living with HIV (PLWH) who experience actinic keratosis. These were skin biopsies that had previously received topical ingenol-3-angelate treatment. Furthermore, the primary CD4 + T cells isolated from HIV-1-positive patients receiving antiretroviral therapy demonstrated that ingenol-B is a very potent reactivator of HIV-1 in both in-vitro and ex-vivo investigations [48]. Furthermore, one of the two non-human primates who were given ingenol-B and the HDAC inhibitor vorinostat had an increased viral load in their cerebrospinal fluid (CSF) [49].

The reactivation of HIV-1 may occur due to the stimulation of the MAPK/ERK signaling pathway, involving the transcription factors NF-κB and AP-1 [50, 51]. In models utilizing Jurkat cell lines and primary CD4 + T lymphocytes, procyanidin C1 trimer (PC1), a flavonoid isolated from plants that activates ERK, has been shown to reactivate HIV-1 [52]. The reactivation of HIV-1 is achieved through the interaction of PC1 with other (LRAs), which synergistically [52].

Upon TCR activation, phosphoinositide 3-kinase (PI3K) transforms membrane (PIP2) into phosphatidylinositol 3,4,5-trisphosphate (PIP3) [53]. That induces the recruitment of AKT kinase to the membrane, ultimately resulting in the stimulation of its substrate [54]. When the PI3K-Akt pathway is triggered, NF-kB moves into the nucleus and becomes active. Lipid phosphatase phosphatase and tensin homolog (PTEN) primarily inhibits the PI3K-Akt pathway [55]. The PTEN dephosphorylates cellular proteins which results in the reactivation of HIV in the ex-vivo and in- vitro experimental models [53]. Disulfiram has been shown to reduce PTEN levels, which consequently increases AKT signaling. Disulfiram, a common drug acknowledged by the Food and Drug Administration (FDA) to treat alcohol use disorders, has been shown in two clinical trials to not significantly lower the persistent reservoir of HIV-1 in people on antiretroviral therapy (ART) [56]. A recent phase II trial found that short-duration treatment increases unspliced HIV-1 infection RNA at all dosages in HIV patients on suppressive ART, despite disulfiram’s tendency to produce latent HIV in-vivo. This result implies that there is not enough activation to considerably lower the latent reservoirs. Positive transcription elongation factor b (P-TEFb) is recruited when the PI3K-Akt pathway is momentarily stimulated by hexamethylene bisacetamide (HMBA). P-TEFb has the ability to start viral RNA transcription and reactivation [57]. Recent discoveries indicate that HMBA can promote transcription initiation by facilitating the degradation of IκBα and prostratin-induced phosphorylation, as well as by promoting NF-κB’s movement into the nucleus [56].

Second mitochondria-derived activator of caspase (SMAC) mimetics are those that impede the function of the inhibitor of apoptosis proteins (IAPs) [58]. XIAP, cIAP1, and cIAP2 are good instances of IAPs. These kinds of proteins subsequently connect with the caspases and block their function, preventing apoptosis and guaranteeing the cells’ survival [59, 60]. During the reversion of the latent HIV-1 infection, the utilization of cIAP1 is crucial in preventing the activation of the other NF-kB pathway. This is accomplished through the selective loss of NF-inducing kinase (NIK), as described by [60]. A suppression of cIAP1 by SMAC mimetics causes NIK to build up, IKK, alpha, phosphorylation and NF- 0 activation by a non-canonical pathway, eventually reactivating dormant HIV-1 [61]. Many SMAC mimetics have been examined in the search of effective cure of HIV-1. The combination of the HDAC inhibitor panobinostat and the SMAC mimetic SBI-0637142 showed a synergistic effect of increasing HIV-1 transcription and rejection to latency, which were supported by the interaction of these two drugs, according to a JLat model system. Additionally, it has been demonstrated that another SMAC mimic is remarkably effective in treating latent HIV-1 infection as a latency-reversing agent (LRA) This comes after Pache et al. discovered Ciapavir (SBI-0953294). Ciprofloxacin has expanded HIV-1 reservoirs despite failing to boost T cells in a humanized mouse model [62]. This is after the finding of Ciapavir (SBI-0953294) by Pache et al. In spite of the failure of ciprofloxacin to stimulate T cells in a humanized mouse model, it has increased HIV-1 reservoirs [62]. According to recent research, the SMAC mimic AZD5582 may trigger the alternative NF-kB pathway, which could reactivate HIV-1 in rhesus macaques and SIV RNA in immunodeficient mice receiving antiretroviral therapy [63]. AZD5582, in conjunction with bispecific CD3s antibodies and the HIV envelope protein, helps direct CD8 + T lackeys to HIV-affected cells that express the envelope protein. This leads to viral activity and ultimately the death of the infected cells. Regrettably, this intervention was not effective to decrease the SHIV RNA levels [64]. It was also established that AZD5582 and IL-15 super-agonist N-803 have the capacity to activate latent infection in SIV-infected Rhesus macaques under Anti-retroviral therapy [65]. Although different clinical studies have not produced sufficient evidence regarding this subject, our findings indicate that SMAC mimetics have potentials to become therapeutic agents against HIV-1, as they can likewise hasten the elimination of HIV-1 latency. This effect in vitro is increased by using SMAC mimetics together with a PKC activator [66].

Immunotherapy

Moreover, hope exists as far as methods involving antibody-mediated procedures are concerned [67]. Alternatively, the antigenic target of integrins 4 and 7 transposed in the CD⁴⁺ T cells has also become a prominent target, although this may not reflect the viral reservoir well. According to the findings of [68, 69], This integrin facilitates the migration of CD4 + T cells to gut-associated lymphoid tissues (GALT), which prompt Mucosal Addressin Cell Adhesion Molecule 1 (MAdCAM) [70]. It was discovered that SIV infects CD4 + T cells with the 4 and 7 integrating proteins the most effectively. Privatized antibodies which target the 4 and 7 integrin as an alpha4 beta7 offers the protection of macaques against SIV infection at the vagina using the ACT-1 antibody [68]. It is worth noting that treatment was initiated five weeks after the SIV infection, and recent research was carried out by [68]. the results would indicate that a recessive group of macaques might be able to sustain virologic control during up to nine months of cART by the abandonment of ACT-1. Although these findings are quite interesting, it is conceivable that the macaques had intermediate viral reservoirs because of the premature treatment at the age of five. Also, SIV has a greater rate of spontaneous control In comparison with HIV-1. A more recent study has outlined a possible treatment approach that entails the incorporation of alpha4 beta 7 into virions [71]. suggested that anti-alpha 427 antibodies could inhibit viral hepatonosis and/or precoccdinate the progression of new infections, consequently, weakening the viral dispersal ability in the gastrointestinal system. Moreover, the anti-alpha4 7 antibodies known as vedolizumab is utilized to control Crohn. Unless it promotes the development of anti-drug antibodies as it had in three out of eleven macaques under study, it can potentially go a long way in improving the HIV-1 treatment regimen of the infected individuals [68].

Reinvigorating effector T cell exhaustion

Immunological analysis of defective cells is very important and it is the main concern of this review paper. Different variables inhibit the activity and transit of effector cells to target cells, necessitating an investigation of these variables. The examination of these elements will assist us in developing and implementing appropriate treatment plans to address these challenges.

According to [72], in order to properly eradicate HIV-1, CD8 + T lymphocytes must be pre-stimulated in order to produce the cells required to eradicate the infected cells in an HIV-positive individual., even after a period of Cart duration. This is probably necessitated by a lack of enough antigens in such patients. Researchers have shown that CD4 + T lymphocytes, which are specific to the Gag gene, decrease as cART duration increases [73]. The CD8 + T cells’ memory response will be compromised if the HIV-1-specific CD4 + T cells decline. This is because antigen-specific CD4 + lymphocytes are necessary for the development of a robust CD8 + T cell immune memory. Additionally, as stated by [74], Chronic HIV-1 infection causes malfunctioning cytotoxic T lymphocytes (CTLs), which cART cannot repair. According to the literature, the first study was conducted in the mouse lymphocytic choriomeningitis virus (LCMV) system, which was discovered to be a significant malfunction [75]. This was the first data to show that the loss of CD4 + and CD8 + T cells causes cytotoxic T lymphocytes (CTLs) to fail. Long-term immune response stimulation with antigens is correlated with permanent activation, which leads to T cell dysfunction. These conditions are normally present as a result of latent viral infections as seen with cancer or HIV-1 infection cases [76–78]. According to the [79], a decrease in antigen-specific effector and memory T cells causes the T cell population to fall. Effector T cells gradually lose their ability to proliferate and function as a result of this decline, which ultimately results in their eradication. When compared to mature terminally differentiated or memory CD8 + T cells, exhausted CD8 + T cells display distinct epigenetic and transcriptional traits. Reduced cytokine levels and unique expression of inhibitory receptors on their surface, such as Cluster of Differentiation 160 (CD160), Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4), T-cell Immunoglobulin and Mucin-domain containing-3 (Tim-3), T-cell Immunoglobulin and ITIM Domain (TIGIT), and Programmed Cell Death Protein 1 (PD-1) [46, 79, 80]. Immune checkpoints are then created to prevent unwarranted T cell activation as a result of increased expression of inhibitory receptors on the T cell surface. Long-term antigen exposure encourages persistent high expression of these receptors on the cell surface, despite the fact that inhibitory receptor expression is normally inhibited following an immune response. Reviving worn-out antiviral T cells requires targeting and blocking these receptors [81]. Furthermore, CD8 + T cells that are targeting cancer antigens [82] found that treatment combinations can enhance the reestablishment of CD8 + T cell activity during checkpoint suppression. CD8 + T cells exhibit a variety of responses to checkpoint inhibition. Since the discovery of checkpoint inhibitors, many have been used synergistically with cancer immunotherapy, significantly revolutionizing the field of oncology. Combination therapy may be helpful during the “kill” stage of “shock and kill” tactics. Reducing the antigen load that T cells come into contact with should help them feel less exhausted if extended antigen exposure causes this [83], CD8 + T cells targeting HIV-1, collected during the acute infection phase from untreated patients, exhibit signs of exhaustion. These characteristics are reduced by cART or through epitope escape. However, effector functions may remain poorly restored even when there is little or no sustained antigen, as observed in patients undergoing suppressive cART. PD-1 and TIGIT are expressed at higher levels in lymph nodes by all CD8 + T cell types, including follicular and non-follicular cells. It has been discovered that HIV-1-specific CD8 + T cells can function again when the PD-1PD-L1 axis is inhibited in vitro [84]. Certain subsets of immune checkpoints may be involved in latency, according to observations of particular immune checkpoint markers on individual memory CD4 + T cells that are linked to increased HIV-1 DNA copy levels [85]. Therefore, by increasing the activity of cytotoxic T lymphocytes, especially CD8 + T cells expressing CXCR5 in lymph nodes, and by targeting elements of the latent reservoir, anti-PD-1 and anti-PD-L1 antibodies may improve HIV-1 eradication efforts. A phase I randomized clinical trial employing anti-PD-L1 antibodies supports this [86]. It was observed that the responses of CD8 + T cells were specifically enhanced for the Gag gene among participants. The removal of latent HIV by the immune system is shown in Fig. 2.

Fig. 2.

Diagram illustrating pathways of HIV infection and establishment of the latent reservoir in CD4⁺ T cells. HIV can directly infect activated CD4⁺ T cells, leading to reverse transcription, integration, viral gene expression, and production of virions, followed by immune clearance or cell death. Alternatively, infection of resting or memory CD4⁺ T cells (including Tcm, Ttm, and Trm subsets) can result in transcriptionally silent, latently infected reservoir cells

Reduced CTL functionality and movement into lymph gland

When it comes to eliminating infected cells, antigen identification and impaired effector cells are not the only obstacles hindering this process. The proximity of effector cells to target cells presents an additional challenge. Many target cells reside in lymphoid tissues, including lymph nodes. According to Veazey et al., [87], the CD4 + T cells of GALT are the main targets during an acute infection. The GALT is home to the majority of the body’s lymphocytes.

We have discerned considerable concentration of proviral DNA to the GALT related CD4 + T lymphocytes of the patients with HIV in ART. This is quantified at about five thousand copies per million of cells that is about five times greater than traces of same in the circulating cells [88]. It has also been discovered that the increased expression of CCR5 and the overall increased stimulation of CD4 + T cells may indicate that these cells are more vulnerable to infection than previously thought [67].

Despite continuous debates over GALT’s function is a major HIV-1 reservoir [89, 90]. Because the gut-associated lymphoid tissue (GALT) serves as an HIV-1 repository, it is important to develop therapy strategies that can effectively target the infected cells in GALT. As per to McGary et al. (2017), the researchers have previously described CTLA4 + CD4 + T cells as the main target of infection in the first stages in the T cell zone of lymph nodes. Another significant CD4 + cell compartment that generates HIV-1 is the CD4 + T follicular helper (Tfh) subset, which is located within the B cell follicles [91–93]. This compartment is essential to the production of HIV-1.

Once the reservoirs have been eliminated, it may be necessary to infect T follicular helper (Tfh) cells with HIV-1, which is then eliminated by CTLs, killing the reservoirs. As observed by, there are two possible approaches to this problem [94], These include B-cell-depleting antibodies such as anti-CD20, which temporarily destabilize B cell follicles, and anti-CD40L, which inhibits B and T cell interactions. Both of these methods can be very effective and are already under investigation as a possible way out. Besides, as CCR7low CXCR5hi CD8 + cells may invade the follicles of B cells in the later period of the infection and terminal AIDS, it is significant to develop therapeutic vaccination techniques that would improve the effector cell phenotype [94, 95]. The cytotoxic T cells in lymph nodes have several distinct characteristics that set them apart from the lymphocytes in circulation, this study conducted by [95]. In HIV-positive patients mature, terminally differentiated effector CD8 + T lymphocytes are less frequent in the lymph nodes as compared to circulating lymphocytes. According to [95] and [84], the ability of lymph node (CTLs) to destroy target cells is selective. They, however, have lesser concentrations of perforin, a key inducer of cytolysis. As a result, CTLs have a lesser capacity to kill target cells. As an example, with regard to patients with HIV [96]. Research of the gastrointestinal mucous mucosal tissue produced findings that had the same result with previous studies. These divergences can be explained by the variations in the control of the expression of the genes in CTLs of the lymph glands and in the blood of the circulatory [95]. Moreover, it has been suggested that some LRA, including TLR7 agonist GS-9620, can improve the cytotoxicity of CD8 + T cells [97]. Therefore, by using the evidence at our disposal we would expect these LRAs to be used to attain this objective. Table 2 shows the preclinical trials of the various studies that are designed to activate the latent HIV.

Table 2.

Represents different compounds used to activate latent HIV and different pre-clinical trials studies

LRA Class	Mechanism	Compounds		Pre-clinical trials In Vitro Ex Vivo In Vivo			Minimizing viral load
PKC Agonists [42, 45, 98]	Activation of NF-κB	Phorbol esters	Prostratin	Reversal of HIV-1 latency	Reversal of HIV-1 latency		n.a.
			12- Deoxyphorbol 13- phenylacetate (DPP)	Reversal of HIV-1 latency	Reversal of HIV-1 latency		n.a.
PKC Agonists [52]	Activation of NF-κB	Diterpenes	Ingenol and derivatives	HIV-1 transcription’s Reactivation	Reactivation of HIV-1 transcription	Evaluated in non-human animals and individuals with HIV-1	yes/yes
MAPK agonist [56, 99]	Activation of MAPK	Procyanidin C1		Reactivation of HIV-1 transcription	Reactivation of HIV-1 transcription		n.a.
Activator of Akt pathway [17, 99]	Activation of NF-κB	Disulfiram Hexamethylenebisacetamide (HMBA) 57,704		Reactivation of HIV-1 transcription	Reactivation of HIV-1 transcription	Phase1 and 2 clinical trails	yes/no
				Reactivation of HIV-1 transcription	interreption of HIV-1 latency	Phase 2 clinical study in the context of malignancies	n.a.
				Reactivation of HIV-1 transcription	Reactivation of HIV-1 transcription		n.a.
Immune modulatory LRAs [17, 100, 101]	Activation of NF-κB	Toll-Like receptor agonists	TLR1/2 (Pam3CSK4)	Reactivation of HIV-1 gene expression	Reactivation of HIV-1 gene expression		n.a.
			TLR5 (Flagellin)		Reactivation of HIV-1 gene expression		n.a.
	Anti-anergic	Immune checkpoint inhibitors	Anti-PD-1		HIV-1 latency reversal	Clinical testing in HIV-1-infected individuals	yes/no
			Anti-CTLA-4			Phase1 clinical trial in HIV-1-infected adults	yes/no
Epigenetic modifiers [102–104]	Opening of chromatin to allow transcription	HDACi	TrichostatinA Trapoxin Romidepsin Vorinostat Entinostat Valproicacid Fimepinostat Chidamide Panobinostat	Reactivation of HIV-1 transcription	HIV-1 latency reversal	Thoroughly examined in clinical trials	yes/no
		HMTi	Chaetocin BIX-01294		Reactivation of HIV-1 gene expression		n.a.
		DNMTi	5-aza-cytidine 5-aza deoxycytidine zebularine	Reactivation of HIV-1	Reactivation of HIV-1		n.a.
SMAC mimetics [63]	Induction of the non-canonical NF-κB pathway	SBI-0637142		HIV-1 latency reversal	HIV-1 latency reversal		n.a.
		AZD5582				Reactivity of the HIV-1 gene in investigations with rhesus macaques	n.a.
STAT5 sumoyla-tion inhibitors [105, 106]	Activation of STAT5	1-hydroxy benzotriazole and derivatives		expression of the HIV-1 gene	expression of the HIV-1 gene	Phase1trial	n.a
BET inhibitors [106]	Release of P-TEFb	JQ1		Reversal of HIV-1 latency	Reversal of HIV-1 latency		n.a
		I-BET and I-BET151				Reactivation of HIV-1 gene	n.a
CCR5 antagonists [38, 107]	Activation of NF-κB	Maraviroc HIV-1 latency reversal		Reversal of HIV-1 latency	No activation	Phase 2 clinical trial	no/no
Tat vaccines [108]	Activation of HIV-1 L	Tat-R5M4 protein Reactivation of latent HIV infected cells		Reversal of HIV-1 latency	Reversal of HIV-1 latency		n.a.

Natural killer cell immune escape and immunotherapy strategies

Adopted by the T-cells are efforts to improve T-cell-mediated cytolytic responses in hopes of discovering a treatment for HIV-1. This is founded on the high selective pressure that T-cells have on the virus. Some patients have been linked with a reduction in virus due to the action of cytotoxic T lymphocytes [109, 110]. Conversely, naturally occurring killer cells, also referred to as NK cells, can help in a big way to improve treatment measures. NK cells, which are probably responsible for eliminating infected cells in antibody-mediated processes as previously mentioned, are also strongly linked to the outcome of HIV-1 and SIV control [111, 112]. These studies have demonstrated the significance of natural killer (NK) cells in the regulation of HIV-1 and SIV. NK cells have been found in African green monkeys, which are natural hosts of SIV but do not develop AIDS [40, 113–115]. These cells are significant since they have been seen both inside and outside of lymph nodes.

NK cells come in two main varieties, and humans have both of them. The placement of their bodies defines these cells. Researchers have observed that injecting mature dendritic cells in mice models or giving specific adjuvants may improve the recruiting process [116]. However, when exposed to modest concentrations of interleukin-2 (IL-2), a cytokine generated by T cells themselves, T cells can increase their cytolytic activity [117].

Alter et al. [111] found that, in addition to CTL-mediated immunological pressure, viral sequence changes may potentially be brought about by NK cell-mediated pressure. This finding supports the presence of CTL-mediated pressure. The hypothesis of this study has been validated by prior investigations and can therefore be considered successful [118]. It was discovered that the balance between inhibitory and activating receptors is responsible for controlling and regulating NK cell activation [119]. NK cells have strong inhibitory receptors called killer cell immunoglobulin-like receptors (KIRs). Certain HLA-A, HLA-B, and HLA-C alleles as well as the bioactive peptides that correspond to them on the cell surface can be particularly recognized by KIRs. The characteristics of peptides that bind with MHC molecules may be changed by mutations in the HIV-1 sequence. These alterations could have an impact on inhibitor binding, which would then alter the activity of NK and regulatory T cells [120]. According to [111], HIV-infected patients with a polymorphic KIR2DL, which is an inhibitory receptor, have pronounced modifications of the Env protein and viral protein U (Vpu). Even less effectively, NK cells that express KIR2DL can nevertheless eliminate CD4 + T cells that are infected with HIV-1 and have these alterations. The extent to which KIR-related polymorphisms contribute to the accumulation of proviruses in the dormant reservoir is currently poorly understood.

Consequently, the findings report that HIV-positive persons with positive outcomes had more cytotoxic CD56 and NK cells [121]. According to the authors’ theory, this discovery may be explained by how latency-reversing drugs alter the expression of NK receptor ligands on virus-harboring cells (CD4 + T cells). The observation of high NK cell levels in these people corroborated this hypothesis. Later studies by Hua and associates in 2017 [122] reported that, once administered, PEG-IFN-alpha increases natural killer (NK) cell activation in co-infected HIV-1 and hepatitis C patients who were also receiving long-term suppressive combinational antiretroviral therapy. The findings demonstrated a statistically significant correlation between the decrease in integrated proviral DNA and the quantity of CD56-positive NK cells. The evidence presented further demonstrates that the two types of NK cells aid in the cytotoxic elimination of infected target cells in the context of HIV-1 activity. Therefore, pharmacological treatments that stimulate NK cells by increasing the expression of activator receptors and lowering the expression of inhibitory receptors may aid in the elimination of latently infected cells during the latency reversal process.

This is due to the fact that these treatments can raise activation receptor expression. Most recently, it was shown that the immune systems of mice, macaques, and humans include memory-like natural killer (NK) cells. Several studies [123, 124] have demonstrated that such cells usually have a greater concentration of the stimulating receptor NKG2C. Five years following the use of the Ad26 vaccine, the memory-like NK cells in macaques were found (Bruant et al. 2018) [124]. With such a discovery, there seems to be no need to consider that the longevity of these cells will necessitate a prolonged presence of antigens. Alternatively, the probability is that such cells may also be produced in the process of an immunization directed. However, the research on the NK cell memory is a more or less recent area, which is full of doubts because of its interest. According to the findings of [125], the exact ratios of cells which act as memory responders and what ligands activate memory in NK cells is yet to be determined. Furthermore, it is unknown if these memory cells can speed up effector function following HIV-1 virus reactivation. It is unclear how many mutations pertaining to natural killer cells will be changed in the reservoir, suggesting that these changes may raise the threshold of these cells by fortifying the repressive receptors. The ambiguity in the existing data supports this claim. Regardless of these gaps, there is great need to know the underlying mechanisms in the memory of NK cells to SIV and HIV-1 in order to meet the objective of finding the vaccine induced cytolytic therapies. Table 3 summarizes the clinical trials that were undertaken to destroy HIV reservoirs.

Table 3.

Represents the clinical trials of the elimination of latent HIV reservoirs

Strategy	Clinical Trial Start and end date.	Approach	End Point	Summary of Results	References
Viral induction	NCT01319383 Feb 2011- 31-03-2016	Vorinostat	HIV gag RNA linked with cells in quiescent CD4⁺ T lymphocytes	An average increase of 4.5 times in unregulated gag mRNA	[126]
Viral induction	NCT01365065 2011-05- 2018-01	Vorinostat,	HIV RNA and DNA are linked with cells	Ongoing	[127]
Viral induction	NCT01286259 2011-01 2014-05	Disulfiram,	HIV RNA and DNA are linked with cells	Elevation in viral load while a decrease in viral reservoirs	[128]
Viral clearance	NCT01070549 Date not available	Therapeutic innoculation with HIV-pox-based vaccine;	Reservoir size (IUPM)	Decline of latent HIV reservoirs	[129]
Viral induction and clearance	ACTG5301 Date no available	Anti-PD-1 antibodies	In development	N/A	–
Creation of HIV-resistant cells	NCT00842634 2009-01 2013-01	SB-728-T;	CD4⁺ T-cell numbers, HIV DNA, and persistence	Increase in CD4⁺ T-cell counts, modified	[130]
Creation of HIV-resistant cells	NCT01044654 2009-12 2014-12 NCT01252641 2010-11 2015-05	SB-728-T;	CD4⁺ T-cell quantities and levels of virus	Ongoing	[131]
RNA-based therapeutics	NCT01153646 2010-04 2011-01	Transplantation of HSCs	Surveillance of vector-expressed RNAs	Vector-produced RNA was identified for a duration of up to 24 months post-transplantation.	[132]

Recent developments in HIV cure research (Post-2020)

Tat inhibitor dCA

Didehydro-cortistatin A (dCA) is a powerful Tat block who keeps the HIV in the severely dormant form. This is aimed at the fundamental territory of Tat, so it cannot recruit P-TEFb, thereby bringing transcriptional elongation to a stop. Conversely, the dCA reinforces the block-and-lock strategy, which promotes heterochromatin formation and inactivates proviral DNA at the HIV (LTR) level [133]. Major preclinical results have shown impressive results; i.e. dCA when given daily was showing ability to delay viral rebound to day 19 in BLT humanized mice, whereas in the control, it delayed it to day 10 [134]. In vitro, long-lasting therapy of primary CD4 + T cells with dCA abolished virus production with several months without rebound, much greater than ART alone. More recent work has studied effects of dCA on host cells: a study of 2024 showed prolonged exposure of dCA results in reprogramming of cells (CD4 + T) to be tolerogenic, acquired a Th2/Treg-like gene expression pattern, inhibits inflammatory responses and inhibits mechanisms that facilitate HIV infection. These results show that dCA is able not only to suppress HIV transcription but also reduce immune activation and vulnerability [135].

Lens Epithelium-Derived growth factor integrase inhibitors (LEDGINs)

Integrase inhibitors are LEDGINs, which interact with LEDGF/p75 host cofactor. Such inhibitors fit into the LEDGF/p75 binding pocket and, thus, push out LEDGF/p75, directing HIV insertion to transcriptionally silent locations. In particular, LEDGINs remodel HIV integration at sites of euchromatin characterized by the presence of H3K36me2/3 and instruct the inner nucleus to integrate HIV [136]. This aberrant integration silences transcriptional activity of the proviruses making the remaining viral reservoir refractory to reactivation. In vitro and animal experiments show that in the presence of LEDGINs, although the parts of the proviruses integrated are removed, a deep latency with strong block and no reactivation of the proviruses integrated in the case of LEDGIN treatment has been noticed [137]. Key findings include preclinical evidence showing that LEDGINs significantly reduce viral replication and alter the integration pattern. Rodent and cell-line models reveal that LEDGIN treatment results in a lower percentage of silent, latency-reversing agent (LRA)-resistant proviruses [137]. The cells exposed to LEDGINs contained significantly fewer inducible proviruses and produced smaller virions. Furthermore, combining LEDGINs with other epigenetic agents has been explored; one study found that the block-and-lock effect was synergistically enhanced by the addition of a BRD4 modulator (ZL0580).

N-803 (IL-15 Superagonist)

The IL-15 superagonist N-803 (formerly known as ALT-803) is made up of an IL-15N72D mutant complexed with the α domain of the IL-15 receptor. It is an engineered cytokine with approximately 25-fold greater biological activity than native IL-15 [138]. N-803 activates the IL-15 receptor signaling pathway (JAK1/3 → STAT5), a powerful stimulator of CD8 + T cells and NK cells. Unlike most small-molecule LRAs, N-803 primarily acts as an immunological stimulator of effector functions but can also induce viral latency reversal in some cases. In animal models, N-803 promotes the migration of HIV-specific CD8 + T cells and NK cells to germinal centers and lymphoid tissues [139].

Broadly neutralizing antibodies (bNAbs) combined with LRAs

Targeting conserved epitopes on the HIV envelope (Env), broadly neutralizing antibodies (bNAbs) can neutralize free virus particles and cause antibody-dependent cellular cytotoxicity (ADCC) against infected cells. The shock-and-kill strategy involves using bNAbs in combination with l (LRAs), often alongside effector cells, to reactivate latent viruses (shock), followed by bNAbs binding to viral proteins to facilitate the elimination of infected cells. Numerous potent bNAbs have been evaluated, including VRC01, 3BNC117, 10–1074, and PGT121 [140].

Preclinical results: Combinations of passive and active vaccination have shown potential in non-human primate (NHP) models. For example, Walker-Sperling et al. used therapeutic vaccination (Ad26/MVA), the bNAb PGT121, and a TLR7 agonist (vesatolimod) to treat SHIV-infected rhesus macaques. This triple regimen achieved 70% post-ART virologic control, with no viral rebound after ART cessation. Other macaque studies combining bNAbs (such as 3BNC117) with LRAs or TLR agonists have also reported reduced viral reservoirs and delayed rebound. These findings suggest that, when paired with immune stimulators, bNAbs can facilitate the clearance of reactivated infected cells.

Clinical studies: Numerous human trials have examined or are currently investigating bNAbs combined with LRAs. In early trials, single bNAbs like 3BNC117 and VRC01 showed brief reductions in viral load or a little delay in viral rebound in some patients, but these benefits were not enough to produce a cure. Combinations of two to three bNAbs (to prevent resistance) with LRAs or immune modulators, like TLR agonists and PD-1 blockers, are being studied in current trials. For instance, studies are being conducted to assess the use of a TLR9 agonist in conjunction with 10–1074 and 3BNC117 during ART interruption. Non-human primate (NHP) study results are “very promising,” according to reviews, and bNAb and LRA combo clinical trials are ongoing, however full data have not yet been released.

CRISPR, CRISPRi excision

Another strategy that makes use of the CRISPR/Cas9 system has shown promise [141]. A guide RNA that targets conserved areas within the (LTR) structure is co-expressed with the dead Cas9 (dCas9), which is linked to a transcriptional repression domain. This approach aims to specifically target areas of the LTR [142]. Several interconnected strategies have been developed to inhibit HIV transcription through multiple pathways. A guide RNA that targets conserved areas within the (LTR) structure is co-expressed with the dead Cas9 (dCas9), which is linked to a transcriptional repression domain [143]., Altering the structure or folding of TAR RNA [138], and employing TAR-derived RNA traps to capture Tat-P-TEFb in complexes that cannot initiate HIV transcription [144].

Suzuki et al. show that small interfering RNAs (siRNAs) can induce transcriptional silencing of human genes under certain conditions. These siRNAs specifically target promoter regions and can silence human genes. In the case of HIV-LTR instance, this has been shown with the aid of siRNAs of between 21 nucleotides long in double strands and specifically targeted to the enhancer region [145]. The treatment with HDAC) Inhibitors was successful in inhibiting silencing caused by this method [146]. This has been linked to the establishment of repression chromatin marks on the (LTR). In case of methods of recombinant proteins or RNAs, the necessary step is to devise technologies that would allow specific targeting and transfection of recombinant macromolecules or tailored expression vectors into the cell with a latent infection [147].

The reason is that these strategies are important in achieving such tactics. This means that the efficacy of such methods can be determined by identifying appropriate biomarkers. There is a possibility that the HIV-positive people might sometimes switch ART to Lock Down regimen provided they establish one or several measures as outlined in this section. The given approach may be beneficial to those who are resistant to ART or in instances when the virus is already resistant to the existing medications [148]. This treatment method will also be employed to assess whether patients receiving ART experience minimal levels of viral replication. This phase aims to prevent HIV reactivation from its latent form through the application of the devised treatment strategy. It is essential to reduce low concentrations of replication in passively contaminated cells to achieve the goal of preventing viral transmission [149]. This strategy might make it possible to stop treatment after a long enough time, which would help the number of patients who are latently infected with the virus naturally decline. The idea behind CRISPR interference (CRISPRi) is to use nuclease-deactivated Cas9 (dCas9) coupled to transcriptional repressors (such KRAB) to silence HIV proviral transcription. Programmed dCas9-KRAB binds the viral promoter or LTR with guide RNAs (gRNAs) and consequently recruits repressive chromatin modifiers to the provirus. CRISPRi is effectively a gene-specific block-and-lock technique [150]. CRISPRi-mediated silencing is highly effective in in vitro studies. For example, Correia da Costa et al. demonstrated that J-Lat (lymphoid) and U1 (myeloid) cell models transduced with dCas9-KRAB constructs targeting the HIV LTR prevented virus reactivation by a significant margin. Even when stimulated by strong PKC agonists or HDAC inhibitors, the expression of GFP, a reporter of HIV activity in J-Lat cells, was found to be nearly totally repressed when directed to the LTR NF-κB site by a single guide RNA [150]. In U1 cells, a comparable degree of HIV RNA suppression—roughly 100 times—was noted. These results show that CRISPRi may effectively lock HIV in latency in cell lines [151].

Relevant clinical trials (Post-2020)

The aforementioned tactics have been explored or are being tested in a number of recent clinical trials.:

Tat inhibitors (dCA)/LEDGINs

These are still in preclinical phases as of right now. After 2020, there have been no reports of dCA or LEDGIN human trials. Animal models are still being used to assess these substances.

N-803 (IL-15): In a Phase 1 dose-escalation trial published in 2022, subcutaneous N-803 was assessed in ART-suppressed PWH. The trial showed safety and strong NK cell and CD8 + T cell growth, despite not lowering the viral reservoir. HIV RNA and DNA levels in stomach tissue and lymph nodes were shown to be slightly lower in a small open-label research that administered three weekly doses of N-803 (6 µg/kg). Participants are currently being recruited for two Phase II trials: one will test N-803 in conjunction with a dual bNAb combination (VRC07-523LS + 10–1074), while the other will administer N-803 in combination with a (bNAb), teropavimab, following an analytical treatment interval [152].

CRISPR/Cas9 (EBT-101)

In 2022, the first human trial of CRISPR excision therapy (NCT05144386) commenced. AAV9-CRISPR (EBT-101) was administered intravenously as a single dose to five participants. According to interim findings from 2023 to 2024, the treatment was well tolerated and demonstrated adequate biodistribution. However, all three participants who interrupted ART, experienced viral rebound. One individual remained undetectable for 16 weeks off ART, a longer duration than expected. To improve efficacy, a higher-dose cohort is currently being evaluated, and novel delivery methods, such as lipid nanoparticles, are under investigation.

bNAb + LRA trials

Numerous studies have evaluated bNAbs in HIV-positive individuals. For example, research involving 3BNC117, 10–1074, or VRC01 has been conducted both with and without LRAs, such as TLR agonists or romidepsin. The evidence available so far denotes that bNAbs are safe and capable of momentarily decreasing viremia, though some patients had a nearly sluggish viral recovery upon amid bNAbs usage and immune stimulant administration. As an example, a trial involving 3BNC117 and 10–1074 with a TLR9 agonist, a small group of the participants were experiencing prolonged (ART)-free viral control. There are many trials of different bNAb/LRA combinations presented at ClinicalTrials.gov. Even though none of these combinations has shown any long-lasting remission yet, early trends have shown that they might slightly be able to increase the time to viral rebound. These studies are based on encouraging data of non-human primate (NHP) studies [153].

Conclusion

The case of creating an HIV treatment that is safe and scalable, a disease that afflicts around forty million people around the globe is a challenge. This is made more difficult by the intricate processes that lead to the creation of viral latency as well as the characteristics of the latent repository in vivo, which is made up of sporadic but persistent cells that are widely dispersed. After extensive research employing carefully chosen molecular biology systems, primary human cells, cell line models, and advanced in vivo animal models of HIV latency, many possible therapeutic possibilities were discovered. However, there are still some issues with their methods for seeing and attacking reservoir cells. In order to implement the strategy of kicking and killing in the process of eliminating residual virus that may not be entirely eliminated in the early phases of therapeutic interventions, genetically modified cells of the anti-HIV immune system and associated chemicals may be utilized. Broadly neutralizing antibodies (bNAbs) and CAR-T cells are two examples. Compared to lifetime antiretroviral therapy, any potential HIV treatment should have much more advantages and/or less side effects. This is necessary as the improvement in therapy has made HIV a lifelong manageable disease to a large number of people. The technique has to activate the dormant HIV in all reservoir cells, in order to become cured. Although this is a limitation, the technique can complement the currently used modalities as it can destroy the remaining reservoir cells that cannot be destroyed by other therapeutic modalities. Despite the effectiveness of transplantations in recipients using CCR5 ∆32 donor cells, it is not sufficient since it is complex, and a limited number of donors are eligible. Gene therapy can be required in order to expand successfully. Block-and-lock methods have the potential to enhance the ART regimens by suppressing the expression of residual HIV proteins. This would result in less continuous immune activation and chronic inflammation of HIV patients receiving treatment. These patients have the challenge of continuously silencing HIV provirus without having to be undergoing pharmaceutical interventions. The possible solution to the restriction of infection is provided by gene editing to modify the cells which can be susceptible or eliminate HIV provirus. To ensure this is successful, however, this should be able to modify reservoir cells without off target effects.

Author contributions

A.Z. and B. B. wrote the text and performed the formal analysis; N.A. and M.Y.S. curated the data. A.M.A. handled the conceptualization and writing edits.

Funding

This Study was funded by the Deanship of Research and Graduate Studies at King Khalid University through Large Research Project under grant number RGP2/497/46.

Data availability

This study did not gather or create any underlying data.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Clinical trial number

Not relevant.