Immunoglobulin Content and Antibody Activity in Urine in Experimental Urinary Tract Infection

Immunoglobulin content and antibody content in urine were analyzed in rabbits following experimental urinary tract infection. IgA was present in urine from normal animals and in animals with urinary tract infection. Since it was present in urine whether it was synthesized locally or not, IgA in urine probably represents IgA excreted from serum. IgG was not present in urine from normal rabbits, but was present in urine from some animals with pyelonephritis. This IgG migrated as a fast component immunoelectrophoretically, had antibody activity, and had the capability of crossing renal and intestinal epithelium. This unique IgG probably represents IgG synthesized by a restricted population of cells within the infected kidney. IgG was present in urine from all animals with bladder infection and represents newly synthesized IgG which can cross the inflamed bladder mucosa.