Production of tumor necrosis factor-alpha and lymphotoxin by cells of Hodgkin's neoplastic cell lines HDLM-1 and KM-H2

Abstract

The production of tumor necrosis factors (TNF) from cells of two Hodgkin's Reed-Sternberg (H-RS) lines, HDLM-1 and KM-H2 was examined. The culture supernatant from these two types of H-RS cells exerts a cytotoxic effect on L929 cells. Both tumor necrosis factor (TNF-alpha) and lymphotoxin (TNF-beta) are responsible for this activity. This was confirmed by the presence in the cells of proteins and m-RNAs of TNF-alpha and TNF-beta, as determined with immunoperoxidase staining and Northern blot hybridization. Approximately 20% of HDLM cells and 5% of KM-H2 cells were positively stained by a monoclonal anti-TNF-alpha antibody, and this staining was inhibited by preabsorption of the antibody with recombinant TNF-alpha. Staining with anti-TNF-beta, however, showed an intense reaction in more than 60% of HDLM-1 cells, but only in 5% to 10% of KM-H2 cells. The abundant expression of TNF-beta in HDLM-1 cells is consistent with approximately 10 times the TNF activity in HDLM-1-conditioned medium as compared with that of KM-H2. The rich secretion of TNF-beta in HDLM-1 cells was also validated by the inhibition of most of the TNF activity in HDLM-1-conditioned medium with anti-TNF-beta antibody, and by the presence of abundant TNF-beta mRNA in HDLM-1 cells. The reason for the abundant production of TNF-beta in HDLM-1 cells is not yet known, but may be attributable to a chromosomal abnormality in the 6p21 region. The expression of TNF-alpha, but not TNF-beta, by H-RS cells was demonstrated in lymph nodes from patients with Hodgkin's disease. The capacity of H-RS cells to secrete TNF as well as other cytokines, such as interleukin-1, colony-stimulating factors, and transforming growth factors, may contribute to the unique clinical and histopathologic alterations in patients with Hodgkin's disease.