Humoral autoimmune response to ribosomal P proteins in chronic Chagas heart disease
The C terminal region of a Trypanosoma cruzi ribosomal P protein, encoded by the λgtll JL5 recombinant, defined a major antigenic determinant in chronic Chagas heart disease. Immunopurified anti‐JL5 antibodies were tested for anti‐human ribosome reactivity by immunoblotting. They recognized the parasite ribosomal P proteins and clearly reacted with the corresponding human P proteins. The peptide R‐13, that comprises the 13 C terminal residues of the JL5 recombinant and defines the specificity shared between chronic Chagas heart disease anti‐JL5 antibodies and the systemic lupus erythematosus (SLE) anti‐P antibodies, was used to study the specificity and the IgG subclass distribution of the anti‐R‐13 response by ELISA. The R‐13 autoepitope is recognized mainly by sera from chagasic patients, but not by sera from malaria patients. Moreover, there was a significant correlation between anti‐R‐13 antibody levels and anti‐T. cruzi antibody titres. The anti‐R‐13 response was mainly restricted to the IgG1 heavy chain isotype and correlated with the anti‐T. cruzi isotype distribution.