Anti-K562 cell monoclonal antibodies recognize hematopoietic progenitors.

Abstract

The [human] K562 leukemia cell has properties of self-renewal and pluripotency similar to those of the hematopoietic stem cell. [Mouse] monoclonal antibodies to K562 cells were produced using hybridomas technology. By radioimmunoassay, some anti-K562 cell antibodies also bind to erythrocyte antigens or peripheral blood mononuclear cells; others are more specific for K562 cells. Antibody binding to hematopoietic progenitors was assayed by using the ability of these cells to form colonies in vitro. After exposure of human bone marrow cells to anti-K562 antibodies and complement, myeloid or erythroid clony formation was inhibited some of the inhibitory antibodies showed little little to mature blood cells by radioimmunoassay, immunofluorescence and complement cytotoxicity, suggesting that they recognize antigens specific to undifferentiated cells. With the fluorescence-activated cell sorter, 1 inhibitory antibody was shown to stain only 3% of bone marrow cells. Inhibitory anti-K562 antibodies also bind to myelogenous leukemia cells and virus-transformed lymphocytes. These antibodies appear to recognize antigens shared by normal hematopoietic progenitors, leukemic cells and transformed lymphocytes.