Abstract
A cell surface glycoprotein antigen with an apparent MW of about 100,000 that is selectively expressed on proliferating cells was purified from deoxycholate-solubilized membranes of a cultured human leukemic thymus-derived (T) cell line by affinity chromatography on a monoclonal antibody-Sepharose column. A conventional xenoantiserum prepared by immunization with the affinity-purified glycoprotein was found to contain antibodies against a serum component that bound tightly to cultured cells. This molecule was specifically associated with the cell surface glycoprotein purified by immunoprecipitation from lysates of cells. The serum component was identified as transferrin. Apparently, the membrane glycoprotein is the cell surface transferrin receptor.