B‐Cell Mitogenic Effects on Human Lymphocytes of Rabbit Anti‐Human β2‐Microglobulin

Rabbit Ig against human beta2-microglobulin was found to be mitogenic for human peripheral lymphocytes, tonsil lymphocytes, and appendix and spleen cells. Anti-beta2-m gave increased DNA synthesis, with peak responses on day 3 or 4 and showed a dose-response effect when diluted. The effect was seen in both serum-free and serum-containing culture medium. Anti-beta2-m, as well as lipopolysaccharide, induced polyclonal antibody production and intracellular immunoglobulin synthesis in blast cells, which is taken as evidence that these substances are human B-cell mitogens. Anti-beta2-m, but not lipopolysaccharide, could, in these experiments, activate peripheral blood lymphocytes, in addition to lymphoid cells from other sources. Thus, anti-beta2-m can serve as a functional marker for peripheral human B lymphocytes.