A genomic clone encoding the alpha chain of the OKM1, LFA-1, and platelet glycoprotein IIb-IIIa molecules.

LFA-1, an antigen involved in cytolytic T lymphocyte-mediated killing, and Mac-1, the receptor for complement component C3bi, constitute a family of structurally and functionally related cell surface glycoproteins involved in cellular interactions. In both mouse and man, Mac-1 (OKM1) and LFA-1 share a common 95-kDa beta subunit but are distinguished by their alpha chains, which have different cellular distributions, apparent molecular masses (165 and 177 kDa, respectively), and peptide maps. We report the isolation of a genomic clone from a human genomic library that on transfection into mouse fibroblasts produced a molecule(s) reactive with monoclonal antibodies to OKM1, to LFA-1, and to platelet glycoprotein IIb-IIIa. This gene was cloned by several cycles of transfection of L cells with a human genomic library cloned in lambda phage Charon 4A and subsequent "rescue" of the lambda phage. Transfection with the purified recombinant lambda DNA yielded a transfectant that expressed the three human alpha chains of OKM1, LFA-1, and glycoprotein IIb-IIIa, presumably in association with the murine beta chain.