Expression of macrophage colony-stimulating factor (M-CSF) in two Hodgkin's Reed-Sternberg (H-RS) cell lines, HDLM-1 and KM-H2, and in H-RS cells in tissues.

The authors studied the production of macrophage colony-stimulating factor (M-CSF) and the expression of its receptor (c-fms) in two Hodgkin's Reed-Sternberg (H-RS) cell lines, HDLM-1 and KM-H2 and in H-RS cells in tissues. We found that both types of H-RS cell can produce M-CSF, as was confirmed by the presence of M-CSF mRNA and protein in the cells and by the presence of macrophage colony-stimulating activity in conditioned medium. M-CSF was also expressed by H-RS cells in lymph nodes from patients with Hodgkin's disease. In cultures, KM-H2 cells appeared to produce a lesser amount of M-CSF than did HDLM-1 cells, as indicated by weaker staining with anti-M-CSF in the former cells. In KM-H2 cells, most of the M-CSF was located in the cytoplasm, and in HDLM-1 cells, in the Golgi apparatus and/or on the cell membrane. The two types of cultured H-RS cell either did not express c-fms at all, or expressed it only extremely weakly, perhaps because of the loss of dependence on specific growth factors during culture. The production of M-CSF by H-RS cells may contribute to the clinical and pathologic changes seen in patients with Hodgkin's disease, such as the increased abundance of histiocytes in tissues infiltrated by H-RS cells. Alternatively, the expression of both M-CSF and c-fms could confer a growth advantage to some H-RS cells in an autocrine fashion.