A NEW BOVINE LEUKOCYTE ANTIGEN CLUSTER COMPRISING 2 MONOCLONAL-ANTIBODIES, CC43 AND CC118, POSSIBLY RELATED TO CD1

Two mAbs, CC43 (012) and CC118 (040), clustered together when the flow cytometric data for staining of target cells was analysed statistical ly. The antigen recognized was present on immature thymocytes but not mature T cells; it was expressed by B cells and monocytes but not by g ranulocytes. Two molecules were evident by SDS-PAGE run under reducing conditions. One had an M(r) of 44 kDa, the other an M(r) of 12 kDa. T he smaller molecule was probably beta2-microglobulin; the larger one w as distinct from bovine CD1b and MHC Class I. The mAb may recognize th e product of a previously unrecognized bovine CD1 gene and should be c onsidered as a novel bovine mAb cluster. The molecule appeared to be p olymorphic and distinct alleles may be expressed on Bos taurus and Bos indicus.