ABSTRACT
Background: We have previously reported that immunization with GRA2 antigen of Toxoplasma gondii induces protective immunity in CBA/J [H2k] and BALB/c mice [H2d]. We aimed to examine whether immunization of a distinct strain of rodent with recombinant dense granule antigens [GRA2] combined with monophosphorryl lipid A [MPL] adjuvant elicits protective immune response against T. gondii
Methods: C57BL/6 [H2b haplotype] mice were immunized with GRA2, formulated in MPL adjuvant
Results: Strong humoral response, predominantly of IgG1 subclass and cellular response, IFN-gamma, was detected at three weeks post immunization. Mice immunized with GRA2 had significantly [p < 0.01] fewer brain cysts than those in the adjuvant group, upon challenge infection. Despite the production of a strong antibody response, IFN-gamma production and brain cyst reduction were not significant when the immunized mice were infected four months after the immunization
Conclusions: We can conclude that GRA2 immunization partially protects against T. gondii infection in C57BL/6 mice, though the potency and longevity of this antigen as a standalone vaccine may vary in distinct genetic backgrounds. This observation further emphasizes the utility of GRA2 for incorporation into a multi-antigenic vaccine against T. gondii