Production of polyclonal antibody against kidney antigens: a model for studying autoantibody in feline chronic kidney diseases.

Chronic kidney disease is considered to be most common in geriatric domestic cats. It has been reported that the feline viral rhinotracheitis, calicivirus, and panleukopenia (FVRCP) vaccine prepared from the Crandell-Rees feline kidney (CRFK) cell line can induce cross-reactions of antibodies with feline kidney tissues. As an anti-cat kidney antibody was not available commercially for this study of autoantibody in cats, the purpose of this study was to produce anti-cat kidney antibody in rabbits for further study of autoantibody in cats after FVRCP vaccination. Kidney proteins from cadaveric cats were extracted and immunized into rabbits using Montanide as the adjuvant. Based on enzyme-linked immunosorbent assay measurement, all immunized rabbits produced high levels of anti-cat kidney antibodies and some began to produce antibodies as early as 2 weeks after immunization. Immunofluorescence staining of rabbit sera showed kidney-bound antibodies in glomerulus, Bowman's capsule, apical surface of the proximal convoluted tubule, peritubular surface, and interstitial cells. Western blot analysis of cat kidney proteins revealed molecular weights (M.W.) of 72, 55, 47, and 31 kDa, while binding to the CRFK cell proteins was observed at M.W. of 43 and 26 kDa. The antibody that recognized the 47 kDa protein was similarly detected in cats with autoantibody presence after FVRCP vaccination. The kidney-bound antibody profile at different time points and its patterns in rabbits could be used as a model for the study of autoantibody to cat kidney in feline chronic kidney diseases.