Studies on a new lymphocyte mitogen from Bordetella pertussis. I. Induction of proliferation and polyclonal antibody formation.

Pertussis B mitogen (PBM), isolated from culture supernatant fluids of Bordetella pertussis, is a potent mitogen for mouse and human lymphocytes. In mice, > 95% of the blast cells recovered from PBM cultures bear surface immunoglobulins. Therefore, PBM seems to induce proliferation of mouse B lymphocytes, but not T cells. The proliferative response observed is nonspecific because cells from all mouse strains tested, including germfree animals, are responsive. Moreover, the mitogenic activity of PBM is independent of T lymphocytes, macrophages, or serum factors. When human peripheral blood or cord blood lymphocytes are cultured in the presence of PBM, a high level of thymidine incorporation by these cells is detected. Furthermore, PBM can induce polyclonal antibody formation by both mouse and human lymphocytes. Despite similar methods of isolation, PBM is distinct from the lymphocytosis-promoting factor of B. pertussis, a previously described T cell mitogen.