Persistent and enhanced expression of c-fos gene products in various kinds of human hematopoietic cell lines. Immunofluorescence study using prepared monoclonal antibodies

Two kinds of monoclonal antibodies recognizing fos proto-oncogene (c-fos) products were prepared using a synthetic oligopeptide corresponding to amino acids 127-152 of the fos oncogene products. These monoclonal antibodies (FO-120 & FO-145) detected fos gene products induced in a human monocyte cell line (U-937) by phorbol acetate (TPA) and induced in both human and mouse fibroblast cell lines (284, BALB/c 3T3) by serum-stimulation. One of the monoclonal antibodies (FO-120) reacted with 50-kDa and 42-kDa proteins and the other antibody (FO-145) reacted with a 30-33-kDa protein. The expression of the fos gene in various human hematopoietic cell lines was investigated using these prepared monoclonal antibodies. While almost all hematopoietic cell lines tested reacted with these monoclonal antibodies to various degrees, the majority of normal peripheral blood lymphocytes cultured with lectin (PHA) and interleukin 2 (IL-2) did not, suggesting that cells of some permanent hematopoietic cell lines, irrespective of their lineage specificity and growth factor dependency, continuously express the fos oncogene. These monoclonal antibodies may be useful for detecting early neoplastic changes in hematopoietic cells.