PRODUCTION AND EPITOPIC CHARACTERIZATION OF MONOCLONAL-ANTIBODIES AGAINST BOVINE BETA-LACTOGLOBULIN

Sixty-nine murine monoclonal antibodies were produced against the bovi ne beta-lactoglobulin (beta-LG) variant B. Thirty-eight specificity gr oups of monoclonal antibodies were defined according to the reactivity in indirect or capture ELISA with bovine beta-LG B, for bovine beta-L G B coated at pH ranging from 2.3 to 9.4, and for beta-LG with natural ly occurring residue substitutions such as bovine beta-LG variant A an d ovine, caprine, porcine, and equine beta-LG. Ten monoclonal antibodi es appeared to be monospecific for bovine beta-LG, 58 monoclonal antib odies recognized only ruminants beta-LG, and 1 recognized all species. The specificity of the monoclonal antibodies was also studied with se quenced tryptic peptides of beta-LG variant B. Critical residues invol ved in the epitopes of nine classes of monoclonal antibodies were char acterized. Moreover, 5 monoclonal antibodies were able to discriminate between a fresh solution of beta-LG and a solution that had been stor ed for greater than or equal to 2 d at 4 degrees C, and 3 monoclonal a ntibodies distinguished bovine beta-LG that has been purified by gel f iltration from that purified by salt fractionation. This array of mono clonal antibodies could be efficient probes for characterizing conform ational structures involved in biological properties of beta-LG (e.g., interaction with ligands and hypersensitivity reactions) and for stud ying conformational changes occurring upon physical treatments such as heat denaturation.