Characterization of monoclonal antibodies assigned to the CD45 subgroup of the Third International Swine CD Workshop

As a result of the first-round cluster analysis, a panel of 16 novel monoclonal antibodies (mAbs) was assigned for detailed analysis to the CD45 subgroup of the Third International Swine CD Workshop. The specificity of the mAbs was initially determined by examining their reactivity with Chinese hamster ovary (CHO) cells engineered to express individual isoforms of porcine CD45. These analyses indicated that seven of the mAbs (PG77A, PG96A, PG167A, PGB78A, 3C/9, MIL13, NHT 101) recognized the portion of the CD45 molecule encoded by the A exon (CD45RA), while one (MIL15) was specific for that portion encoded by the C exon (CD45RC). In each case, the designation was supported by the demonstration that the molecular weight(s) of the recognized antigen(s) in porcine mononuclear cells, as determined by immunoprecipitation, corresponded to the predicted size(s) according to their specificity. As expected, a similar correlation was obtained for five standard mAbs whose specificity for either common or restricted epitopes of porcine CD45 had been established in previous workshops. Screening of the remaining 174 mAbs that comprised this workshop but were excluded from the CD45 subgroup by cluster analysis failed to detect any additional ones reactive with the porcine CD45-expressing cells.