Biochemical analysis of molecules reactive with monoclonal antibodies specific for porcine CD45

The apparent molecular weight of molecules reactive with eight mAbs, which were identified during the First International Swine CD Workshop as putatively specific for porcine CD45, was determined by immunoprecipitation analysis of ¹²⁵I surface-labeled peripheral blood mononuclear cells. Four putative CD45 specific mAbs (K252. 1E4, MAC323, 74-9-3 and 2A5) precipitated three polypeptides of 226, 210 and 190 kDa. Two putative CD45R specific mAbs (MAC326 and MAC327) precipitated two polypeptides with an apparent molecular weight of 226 and 210 kDa, while another two (3a56 and -a2) precipitated a single polypeptide of 210 kDa. Sequential immunoprecipitations analyses indicated that the comigrating molecules precipitated by the CD45 and CD45R were the same. The results from this study confirmed the assignment of mAbs K252.1E4, MAC323, 74-9-3 and 2A5 as CD45, and mAbs MAC326, MAC327, 3a56 and -a2, as CD45R. These CD45 and CD45R specific mAbs should prove to be valuable reagents for the study of the porcine immune system.