Appearance of immunoglobulin classes and complement (C3) during Corynebacterium renale-induced experimental...

The local appearance of various immunoglobulin (Ig) isotypes in the urinary tract during ascending pyelonephritis was studied in rats experimentally infected with Corynebacterium renale. The indirect fluorescent antibody assay was used to detect IgG, IgM, IgA, IgE, and C3 on C renale present in the urine of the experimental animals. Corynebacterium renale coated with IgM and IgG antibodies was found beginning on the 4th day after induced infection, with IgG being the more abundant isotype. Coating with IgA occurred as early as the 4th day, but was less dense than coating with IgG. The presence of C3 on C renale was concurrent with IgM and IgG coating. A significant quantity of IgE could not be identified on antibody-coated C renale. Thus, IgG is the major component of the humoral immune response in this model of ascending pyelonephritis. The IgM early during infection and IgA later during infection seem not to be a major component of the immune response in this model.