A new bovine leukocyte antigen cluster comprising two 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 statistically. The antigen recognized was present on immature thymocytes but not mature T cells; it was expressed by B cells and monocytes but not by granulocytes. 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. The smaller molecule was probably beta 2-microglobulin; the larger one was distinct from bovine CD1b and MHC Class I. The mAb may recognize the product of a previously unrecognized bovine CD1 gene and should be considered as a novel bovine mAb cluster. The molecule appeared to be polymorphic and distinct alleles may be expressed on Bos taurus and Bos indicus.