Résumé
: Our study demonstrates that cholera toxin (CT) markedly enhances the intestinal anti‐T. gondii antibody response following oral immunisation of mice with a T. gondii sonicate (TSo) and CT. The antibodies induced were mostly IgA and secretory IgA but a small quantity of IgG was also produced. In contrast, no intestinal anti‐T. gondii IgM antibodies were detected. Anti‐CT IgA antibodies were also present in intestinal secretions but in much lower quantities than the T. gondii‐specific IgA. No anti‐CT IgG nor IgM antibodies were detected. Western blot analysis showed that CT induced not only an increase of the intensity of the intestinal IgA antibody response to the 30‐kDa band but also induced intestinal IgA antibodies against other major T. gondii proteins (p22, and the 28‐kDa antigen) as recognised by specific monoclonal antibodies. The amplification of the anti‐T. gondii secretory IgA response by means of an appropriate adjuvant may be one major step leading towards an orally induced immune protection against toxoplasmosis.