Table 1.
Different vaccine antigens against human diseases expressed via plastid genome since 2011.
| Vaccine Antigen (Disease) | Expression system | Maximum expression level | Immunological investigation | References |
|---|---|---|---|---|
| VIRAL ANTIGENS | ||||
| Dengue epitope region of E protein of DENV domain I and II (Dengue fever) | Lettuce | Not reported | Cross reaction of antibodies from the sera of dengue patients | Maldaner et al., 2013 |
| Dengue-3 serotype capsid complete premembrane (prM) and truncated envelope (E) protein prM/E (Dengue fever) | Lettuce | Not reported | Not tested | Kanagaraj et al., 2011 |
| Mutated human papillomavirus (HPV)-16 oncoprotein E7 (cervical cancer) | Chlamydomonas reinhardtii | Not reported | Vaccination in mice with algae extracts showed high level of E7-specific antibodies but low activation of E7-specific CD8+ cells | Vlasák et al., 2013 |
| Mutated, attenuated E7 oncoprotein (E7GGG), alone or as a fusion with affinity tags (His6 or FLAG) (cervical cancer) | Chlamydomonas reinhardtii | 0.12% of total soluble protein (TSP) | Induction of specific anti-E7 IgGs and E7-specific T-cell proliferation detected in C57BL/6 mice vaccinated with total Chlamydomonas extract and with affinity-purified protein | Demurtas et al., 2013 |
| E7 translationally fused with β-glucuronidase | Tobacco | GUS-E7 showed expression between 30 and 40 times higher than previously reported for unfused E7 (0.1% of TSP) | Not tested | Morgenfeld et al., 2014 |
| Modified HPV-16 L1 gene fused with glutathione-S-transferase (GST) GST-L1_2xCysM (cervical cancer) | Tobacco | Not detected | Not tested | Hassan et al., 2014 |
| Synthetic gene encoding a C4V3 recombinant protein (HIV) | Tobacco | ~25 μg/g of fresh weight | Plant-derived C4V3 has elicited both systemic and mucosal antibody responses in BALB/c mice, as well as CD4+ T cell proliferation responses | Rubio-Infante et al., 2012 |
| Multiepitopic protein (Multi-HIV) carrying several neutralizing epitopes from both gp120 and gp41 (AIDS) | Tobacco | Protein accumulation levels up to 16 μg/g of fresh tobacco biomass | Multi-HIV protein was able to elicit humoral responses in mice when orally administered | Rosales-Mendoza et al., 2014 |
| HIV-1 capsid protein p24 alone and in fusion with the negative regulatory protein Nef (p24-Nef) (AIDS) | Tobacco | P24 up to ~4% and p24-Nef up to ~40% of TSP | Subcutaneous immunization with purified chloroplast-derived p24 elicited a strong antigen-specific serum IgG response. Oral administration of a partially purified chloroplast-derived p24-Nef fusion protein, used as a booster after subcutaneous injection with either p24 or Nef, also elicited strong antigen-specific serum IgG responses | McCabe et al., 2008; Zhou et al., 2008; Gonzalez-Rabade et al., 2011 |
| Rotavirus VP6 gene (gastroenteritis) | Tobacco | >15% of total leaf protein (TLP) | Not tested | Inka Borchers et al., 2012 |
| BACTERIAL ANTIGENS | ||||
| Cholera toxin subunit B (CTB) fused with acid alpha glucosidase (GAA) CTB-GAA (Cholera, Pompe disease) | Tobacco | Between 0.13 and 0.21% of TLP | CTB-GAA fusion protein significantly suppressed immunoglobulin formation against GAA in Pompe mice | Su et al., 2015a |
| CTB fused with Mycobacterium tuberculosis antigens ESAT-6 and Mtb72F (a fusion polyprotein from two TB antigens, Mtb32 and Mtb39) (Cholera, TB) | Tobacco Lettuce | Maximum expression was 7.5% of TSP in mature tobacco leaves for CTB-ESAT-6 | Hemolysis assay with purified CTB-ESAT6 protein showed partial hemolysis of red blood cells confirming the functionality of ESAT-6 | Lakshmi et al., 2013 |
| Major membrane protein I (mmpI) from Mycobacterium leprae fused with LTB (TB) | Tobacco | Not reported | Not tested | Hassan et al., 2013 |
| EspA and Tir/Intimin antigens from enterohemorrhagic E. coli O157:H7 (hemorrhagic colitis) | Tobacco | Up to 1.4% of TSP | Upon oral administration of tobacco plant leaves high IgG and IgA specific antibodies were detected in serum and feces of mice | Karimi et al., 2013 |
| Domain IV of Bacillus anthracis protective antigen gene [PA(dIV)] (Anthrax) | Tobacco | 5.3% of TSP | Antibody titers of >104 were induced upon intraperitoneal (ip) and oral immunizations with plant derived PA(dIV). Mice challenged with B. anthracis showed 60% and 40% protection upon ip and oral immunization with adjuvanted plant PA(dIV) | Gorantala et al., 2011 |
| Anthrax protective antigen (PV) (Anthrax) | Tobacco | 2.5–4% of TSP | Intraperitoneal and oral immunization with plant PA in murine model indicated high serum PA specific IgG and IgA antibody titers. Oral immunization experiments demonstrated generation of immunoprotective response in mice | Gorantala et al., 2014 |
| PROTOZOAN ANTIGENS | ||||
| Plasmodium falciparum surface protein 25 (Pfs25) and 28 (Pfs28) (Malaria) | Chlamydomonas reinhardtii | 0.5 and 0.2% of TSP, respectively | Antibodies to algae-produced Pfs25 were bond to the surface of in vitro cultured P. falciparum sexual stage parasites and exhibited transmission blocking activity | Gregory et al., 2012 |
| Plasmodium falciparum surface protein (Pfs25) fused to the β subunit of the cholera toxin (CtxB) (Malaria) | Chlamydomonas reinhardtii | 0.09% TSP | Algae produced CtxB-Pfs25 elicited CtxB-specific serum IgG antibodies and both CtxB- and Pfs25-specific secretory IgA antibodies | Gregory et al., 2013 |
| Toxoplasma gondii surface antigen of (SAG1), alone and in fusion with heat shock Protein of Leishmania infantum (LiHsp83) SAG1, chLiHsp83-SAG1 (Toxoplasmosis) | Tobacco | 0.1–0.2 μg/g fresh weight | Human seropositive samples reacted with chloroplast-derived SAG1, oral immunization in mice elicited significant reduction of the cyst burden | Albarracín et al., 2015 |
| T. gondii GRA4 antigen (Toxoplasmosis) | Tobacco | 0.2% of total protein | Oral immunization with chlGRA4 resulted in a decrease of 59% in the brain cyst load of mice compared to control mice. ChlGRA4 immunization elicited both mucosal immune responses | Yácono et al., 2012 |
| Sexual stage antigenic surface protein Pfs48/45 antigen of Plasmodium (Malaria) | Chlamydomonas reinhardtii | Not reported | Not tested | Jones et al., 2013 |
| AUTOANTIGENS | ||||
| Human proinsulin (A, B, C peptides) containing three furin cleavage sites fused with CTB (CTB-PFx3) (Diabetes type-1) | Tobacco Lettuce | 47% of TLP in tobacco 53% of TLP in lettuce | Oral delivery of unprocessed proinsulin bioencapsulated in plant cells or injectable delivery into mice showed reduction in blood glucose levels similar to processed commercial insulin | Boyhan and Daniell, 2011 |
| Human proinsulin gene fused with protein A (Diabetes type-1) | Tobacco | 0.2% of TSP | Not tested | Yarbakht et al., 2015 |
| Exendin-4 (EX4) fused with CTB (Diabetes type-2) | Tobacco | 14.3% of TLP | Upon oral delivery in mice CTB-EX4 stimulated insulin secretion similar to the intraperitoneal injection of commercial EX4 | Kwon et al., 2013 |