Antibody formation in Corynebacterium renale-induced experimental pyelonephritis in the rat.

The immune defense system of the kidney was studied by inducing ascending pyelonephritis in rats with Corynebacterium renale. With the fluorescent antibody technique, C renale organisms were observed in the renal pelvis, but were not coated with antibody until they reached the medulla. Histopathologic evaluation of renal tissues collected serially after inoculation confirmed the presence of infection in the medulla when antibody coating occurred. Serum anti-C renale antibody concentrations increased after antibody-coated bacteria appeared in the urine and kidney. Free anti-C renale antibody was not detected in urine from infected rats, using the microagglutination assay. Antibody coating appears to occur only after C renale organisms invade the medulla during ascending pyelonephritis.