Immune Responses in Parasitic Diseases

The immunologic response of Sprague-Dawley rats infected with Trypanosoma rhodesiense is manifested by glomerulonephritis with IgM and IgGl deposition, activation of both the classic and alternate complement proteins and polyclonal B cell activation as detected by antibody production to native DNA. The role of isotype specific immune responses in protective immunity versus immunopathologic tissue injury has not been determined. The nature of the antigens participating in the immune responses has not been clarified but the apparent differences in the evidence and severity of glomerulonephritis in selected inbred strains of rats suggests that specific regulation of the immune response is potentially of value in both immunity and tissue injury. The lack of the IgGa antibody response in the sera of inbred strains as detected by unfractionated solubilized T. rhodesiense antigen in ELISA, to differentiate between minimal and moderate glomerulonephritis is puzzling. Possible explanations are that the IgG antibody response has no role in immune complex deposition or that the antigen preparation does not discern subtle changes in the immune response. The apparent relationship between the IgM antibody response of glomerulonephritis in the Buffalo strain is of interest and should lead to a further understanding of immunopathogenic mechanisms in the infection. (Author)