The effect of culture supernatants of endothelial cell (EC) lines on the immunoglobulin-M(IgM) synthesis by human B cell line, SKW6-CL4 cells, was investigated. Supernatants of human EC stimulated IgM synthesis, as high as 6-fold, but supernatants of bovine EC did not. This enhancing activity was completely blocked by addition of anti-human B cell stimulatory factor-2/interleukin-6 (BSF-2/IL-6) antibody. These data suggest that human EC might participate in the human antibody production system by producing soluble factor, BSF-2/IL-6.
Animals Antibodies