Variable severity of glomerulonephritis in inbred rats infected with Trypanosoma rhodesiense. Correlation with immunoglobulin class-specific antibody responses to trypanosomal antigens and total IgM levels

Five strains of inbred rats (ACI, BUF, F344, WF and WL) were infected with Trypanosoma rhodesiense and killed at 28 days for renal pathology and serological studies. The BUF strain demonstrated the most consistent and severe glomerulonephritis, accompanied by high titer IgM antibodies to trypanosomes and high total IgM levels. The WL strain demonstrated mild glomerulonephritis but prominent PAS (+) intracytoplasmic inclusions in proximal convoluted tubules, accompanied by low titer IgM antibodies and slightly elevated total IgM levels. All strains had low to medium titer IgGl and IgGa antibodies to trypanosomes. Serial serologic studies in BUF rats showed peak titers of IgM, IgGa and IgG1 antibodies to trypanosomal antigens at 10 days. Immune complexes as measured by a C1q binding assay were elevated at 10 days, 3 days following the first detectable antibody responses, and remained so through the 30th day.