Evidence that antisulfatide autoantibodies from rats experimentally infected with Trypanosoma cruzi bind to homologous neural tissue

Earlier studies in Trypanosoma cruzi-infected rats revealed an increased an tibody activity against sulfatide. a specific constituent of both myelin sh eaths of peripheral nerves and T. cruzi epimastigotes. To investigate furth er the characteristics of such anti-sulfatide antibodies, we analyzed their IgG isotypes as well as their ability to bind to homologous neural host st ructures. Antisulfatide IgG-enriched fractions were obtained from rats acut ely infected with T. cruzi. Immunoglobulin isotypes were determined by an e nzyme-linked immunosorbent assay (ELISA) method to show that IgG2a and, mor e significantly, IgG2b were the predominant isotypes of antisulfatide autoa ntibodies. Further immunofluorescence studies carried out in coronal sectio ns of the rat forebrain revealed. in turn, that antisulfatide antibodies we re capable of reacting with homologous neural tissues. Specific binding of these rat autoantibodies to sulfocerebroside on cell surfaces in vivo may i n theory play some detrimental role, given the reported ability of rat IgG2 b to fix complement or to mediate antibody-dependent cell-mediated cytotoxi city reactions.