Study of TOXO KO vaccine efficiency on the ophtalmological damage bound to Toxoplasmaa gondii, on a mouse model of ocular toxoplasmosis

Purpose The toxoplasmosis is one of the most wild-spread parasitoses, affecting almost a third of the world population, and as the main symptomatic demonstration : eye infringement.The aim of this study is to test, on a murin model, the efficiency of a vaccine candidate named Toxo KO, developped by genetic engineering against this pathology. Methods Ninety Swiss Webster mice (OF1), were filled up with fifty cysts of the 76K strain of Toxoplasmaa gondii (type II). A part of these mice received the TOXO KO vaccine intraperitoneally before. Ophtalmological examination and immunological investigation were performed on aqueous humor samples. The intra retinal cysts were also counted after dissection of the entire retinal tissue. Results After vaccination, we observed a decrease of 69% of ophtalmological damage and 90% of intra-retinal cysts. Besides, this group presented no secretion of IFN-γ in aqueous humor, testifying of an absence of deleterious inflammation in these eyes unlike those of the control group. Conclusion Our results are highly significant. This proof of concept lets think that the forward use of such a tool of prevention is possible, to fight more effectively and prematurely against ocular toxoplasmosis.