Genetic assignment of GP90, leukocyte adhesion glycoprotein to human chromosome 21

Intercellular adhesion among human leukocytes involves a cell-surface glycoprotein with an apparent molecular weight of 90,000 which forms complexes with higher-molecular-weight glycoproteins. A monoclonal antibody (60.3) against this glycoprotein blocks induced adhesion. Here we have shown that the antibody reacts with cell clones carrying human chromosome 21 in lymphocyte hybrids between an AKR mouse thymoma (BW5147) and human concanavalin A-activated peripheral blood lymphocytes. Cell sorting by FACS of a hybrid clone heterogeneous in the expression of the antigen identified by the 60.3 antibody yielded a positive fraction expressing the antigen and carrying human chromosome 21, and a negative fraction lacking both the antigen and chromosome 21. The gene coding for the cell adhesion glycoprotein is thus provisionally assigned to chromosome 21.