Expression of the beta-subunit of the human leukocyte adherence receptor depends upon cell type and stage of differentiation.

Abstract

Using a cDNA clone for the beta-subunit of the receptor on human leukocytes that mediates cellular adherence (CD18), we investigated the lineage specificity of beta-subunit mRNA expression in human hematopoietic cells. Relatively high levels of the beta-subunit mRNA transcript were detected in mature peripheral blood leukocytes, including granulocytes and both resting and PHA-activated T lymphocytes. In contrast, relatively low levels of this transcript were observed in EBV-transformed B cells, in the immature Jurkat T cell line, and in chronic myelogenous leukemia myeloblasts and lymphoblasts. The beta-transcript was undetectable in the K562 chronic myelogenous leukemia blast crisis cell line with erythroblastic characteristics and in cultured skin fibroblasts. Two acute myeloid leukemia samples displayed unusually high levels of this transcript, comparable to levels observed in mature PBL. beta-subunit mRNA expression appeared to be primarily confined to leukocytes. In all cells examined the levels of surface beta-Ag expression paralleled levels of beta-mRNA.