Induction of interleukin-2 and colony-stimulating factors in lymphoid cell cultures activated by mitogenic mycoplasmas.

Mycoplasmal infections often result in chronic inflammatory diseases that involve both local cell proliferation and chemotactic phenomena. To clarify the mechanisms responsible for these inflammatory reactions, we have examined whether nonspecific activation of host lymphocytes by mitogenic mycoplasmas triggers the production of lymphokines, which influence differentiation and proliferation of lymphocytes, macrophages and granulocytes. Mycoplasma pulmonis and M. neurolyticum were tested for their ability to induce production of interleukin-2 (IL-2) and colony-stimulating factors (CSF) by activated lymphoid cells. Mitogenic doses of membranes purified from M. pulmonis, as well as concanavalin A (ConA), induce rat lymphocytes to produce IL-2. Stimulation with the T cell mitogen ConA induces twice the level of IL-2 than does stimulation with M. pulmonis, which activates both rat B- and T-lymphocytes. Unlike these T cell mitogens, M. neurolyticum, which stimulates rat and mouse B-lymphocytes, lacks the ability to induce production of IL-2. Nevertheless, M. neurolyticum stimulates mouse spleen cells to produce in vitro factors capable of stimulating differentiation of bone marrow cells into colonies of macrophages and granulocytes.