Study of resistance to Toxoplasmosis using Tachizoites surface antigens of Toxoplasma gondii in vivo

Taoxoplasma gondii is an important food-borne parasite transmitted primarily from animals to humans through meat consumption, mainly pork and lamb, as well as through oocysts shed by cats. Infection in humans can cause severe fetal malformations, ocular complications or encephalitis. Toxoplasmosis infection during pregnancy, especially in sheep, often results in abortion, representing considerable economic loss.The aim of this study was to investigate whether Toxoplasma gondii surface antigens can protect experimental mice against T. gondii infection. To immunize experiments, we evaluated a virulent strain (RH) for challenge experiments.Surface antigens recovered from tachyzoites in RPMI-1640 culture with MEGA-10. Groups of 17 male mice were intraperitoneally (i.p.) & intrapdermal(i.d) immunized with 2 doses at 10 day intervals. Blood samples were collected from tail veins 21 days after last immunization. Antibody was detected using IFAT. 21 days after the last immunization, both groups were challenged (i.p.) with 2 × 103 RH strain tachyzoites. The results showed an increase of antibody levels after each immunization.Finding showed that immunized mice had longer survival than mice from the control group. Adjuvants play an important role in the efficacy of immunizations.However,suggested that with use of other adjuvants(ISCOM)and surface proteins(P30) for better stimulating the humoral and cellular immune responses.