Table 1.

The main features and functions of some ROPs.

Name	Role of ROPs in T. gondii infection and potential therapeutic strategies
ROP1	ROP 1 can reduce parasite sensitivity in mice and inherent immune limitations in humans [1].
ROP2	ROP2 is an important virulence factor secreted by the parasite into the host cells and has been recommended as a vaccine candidate for toxoplasmosis [2].
ROP4	An oral ROP 4 vaccine helps against lethal T. gondii infection [3].
ROP5	ROP5 is a major determinant of acute toxicity in mice and an immune-related GTPP inhibitor [4].
ROP7	ROP7 can promote inflammasome hyperactivation in ThP-1-derived macrophages by interacting with NLRP 3 [6].
ROP8	ROP8 is expressed during the early stages of infection and plays a key role in PV formation [7].
ROP9	ROP9 is involved in the early stages of host invasion and contains B-cell epitopes. Moreover, a DNA vaccine encoding the ROP 9 gene has shown some immune protection against acute infection [8].
ROP13	ROP13 DNA-based vaccines can act against T. gondii by inducing Th 17-associated cytokine production and has been suggested as potential vaccines to control toxoplasmosis [12].
ROP14	ROP14 is a suitable candidate for routine T. gondii examination [13].
ROP16	ROP16 can induce macrophages to adopt an M2 phenotype [14]. The deletion of ROP16 aggravated adverse pregnancy outcomes in mice [15].
ROP17	ROP17 both can promote the transmission of T. gondii by hijacking monocyte tissue migration and is a vaccine candidate for toxoplasmosis [16].
ROP18	ROP18 inhibits host innate immunity through cGAS-STING signaling [17]. Additionally, ROP18 controls the intracellular proliferation of T. gondii [16].
ROP19	A DNA vaccine encoding ROP19 elicited a significant immune response and provided protection against Toxoplasma challenge [18].
ROP21	ROP21 could serve as a DNA vaccine against toxoplasmosis [18].
ROP22	ROP22 has been recommended as a vaccine candidate for toxoplasmosis [19].
ROP29	ROP29 has been recommended as a vaccine candidate for toxoplasmosis [20].
ROP35	Vaccination with ROP35 triggers strong cell-mediated and humoral immunity and partially induces defense mechanisms against T. gondii [21].
ROP38	ROP38 is a key manipulator of host gene expression and functions in the transformation of tachyzoites to bradyzoites [22]. In early infection, ROP 38 affects parasite invasion and exit and induces the secretion of IL-18 [23].
ROP39	ROP39 mediates an IRGB10-specific parasitic effect and regulates acute Toxoplasma virulence [24].
ROP54	ROP54 has been recommended as a vaccine candidate for toxoplasmosis [25]. ROP54 modulates T. gondii virulence and host GBP2 loading [26].