Characterization of monoclonal antibodies specific for feline serum amyloid (SAA) protein

Serum amyloid A (SAA) has been characterized as an inflammatory marker in many species. In this study, we have developed and characterized monoclonal antibodies (MAbs) against feline SAA (fSAA) derived from culture hybridomas. These hybridomas were produced from the fusion of Balb/c-derived myeloma s/p20-Ag14 and splenocytes from mice immunized with purified recombinant feline SAA (rfSAA). Six hybridomas secreting MAbs, M2, M5, M7, M8, M13, and M15, were selected and subcloned on the basis of their specificity to rfSAA by enzyme-linked immunoabsorbent assay (ELISA), and confirmed based on their specificity to rf-SAA by immunoblot analysis. Out of six clones, two clones (M5 and M7) showed higher reactivity with rf-SAA, and were selected for further analysis of ELISA additivity and Western blot cross-reactivity tests. As a result, M5 and M7 clones recognized the same or excessively near epitopes on rfSAA and reacted with rfSAA, fSAA and equine recombinant SAA, but showed no reaction with human recombinant SAA. Because of their specificity, these MAbs may be usefully applied in studying the measurement of SAA concentration in cat serum.