Human cell-surface glycoprotein with unusual properties.

We report here the identification of human cell-surface glycoprotein with unusual and interesting properties. We initially detected this glycoprotein on the surface of cultured human haematopoietic cell lines by means of a monoclonal antibody. Although it is expressed on all cultured human haematopoietic cell lines tested, including the inducible promyelocytic tumour cell line HL-60 (ref. 1), it is not present in readily detectable amounts on most normal or leukaemic human haematopoietic cells. HL-60 cells, on exposure in vitro to appropriate chemical inducers, undergo morphological and functional differentiation along the granulocytic pathway or into macrophage-like cells. One consequence of in vitro induction in the specific loss of the glycoprotein from the surface of HL-60 cells. The molecule does not, however, seem to be a highly tissue-specific differentiation antigen because it is also found on human tumour cell lines derived from non-haematopoietic tissues. Rather, its expression seems to be related to cell proliferation. Preliminary chemical characterization suggests that the glycoprotein maybe identical to the abnormal glycoprotein previously reported by Bramwell and Harris to be associated with malignancy.