Short communication: Characterization of a monoclonal antibody for κ-casein B of cow's milk1

A monoclonal antibody (antik-B) against an oligopeptide of 23 AA corresponding to the region 131-153 of bovine κ-casein (κ-CN) B was generated using the Human Combinatorial Antibody Library (HuCAL) technology. Both AA substitutions distinguishing κ-CN A and B are located in that region (positions 136 and 148). In this study, the reactivity of antik-B to milk samples collected from cows previously genotyped as CSN3*AA, CSN3*AB, and CSN3*BB was tested. According to Western blot results, antik-B recognized κ-CN B and it showed no cross-reactivity toward κ-CN A and other milk proteins. Furthermore, a modified Western blot method, urea-PAGE Western blot, was set up to assess the reactivity of antik-B toward all isoforms of κ-CN B. In conclusion, antik-B was specific to κ-CN B in milk and it seemed to be reactive toward all its isoforms.