Antibodies against crandell rees feline kidney (CRFK) cell line antigens, α-enolase, and annexin A2 in vaccinated and CRFK hyperinoculated cats

Abstract

Background: Cats inoculated with feline herpesvirus 1, calicivirus, and panleukopenia (FVRCP) vaccines grown on the Crandell Rees feline kidney (CRFK) cell line have been shown to develop anti-CRFK antibodies. The identities of common CRFK antigens are unknown. Hypothesis: Cats inoculated with CRFK lysates and FVRCP vaccines will develop autoantibodies measurable by Western blot immunoassay. Antigens associated with these antibodies can be isolated for further study. Animals: One CRFK hyperinoculated rabbit, 44 age-matched unvaccinated kittens purchased from a commercial vendor. Methods: Commonly recognized CRFK antigens were identified by comparison of Western blot immunoassays using sera from a hyperinoculated rabbit and kittens inoculated with CRFK lysate or 1 of 4 commercially available FVRCP vaccines. Antigens were purified from CRFK lysates and sequenced. Antigen recognition was confirmed by Western blot immunoassay and indirect ELISA for 2 proteins using sera from CRFK and FVRCP inoculated kittens. Results: CRFK antigens 47, 40, and 38kD in size were identified. Protein isolation and sequencing identified 3 CRFK proteins as a-enolase, annexin A2, and macrophage capping protein (MCP). Sera from FVRCP and CRFK inoculated cats were confirmed to recognize annexin A2 and a-enolase by Western blot immunoassay and indirect ELISA. Conclusions and Clinical Relevance: This study validated the use of Western blot immunoassay for detection of antibodies against CRFK proteins and identified 3 CRFK antigens. In humans, a-enolase antibodies are nephritogenic; a-enolase and annexin A2 antibodies have been associated with autoimmune diseases. Further research will be necessary to determine the clinical relevance of these findings. © 2010 by the American College of Veterinary Internal Medicine.