Specific IgA antibodies to Toxoplasma gondii detected by ELISA in sera of non-immunosuppressed BALB/c mice, primary infected with D8 strain and challenged after 45 days with the CH3 or EGS strains (groups 1 and 3, respectively) and non-immunosuppressed BALB/c mice, primary infected with the ME49 strain and challenged after 45 days with the CH3 or EGS strains (groups 10 and 12, respectively). Control groups were infected with the D8 strain (group 5) and ME49 (group 14) and non-challenged.

* significant difference between sera collected before (day 0) and 30 days (day 30) after challenge, p < 0.05.