IMMUNOMODULATION IN-VIVO BY THE MYCOPLASMA-ARTHRITIDIS SUPERANTIGEN, MAM

Mycoplasma arthritidis produces a potent superantigen (MAM) that activ ates specific murine and human T lymphocytes to proliferate and secret e lymphokines. We show here that MAM also influences both T- and B-cel l functions in vivo. Lymphocytes from mice injected with MAM exhibit a suppression of proliferative responses to MAM in vitro but only a par tial suppression of responses to other mitogens. This T-cell anergy no t only decreased contact sensitivity to dinitro-fluorobenzene but also prolonged survival of skin transplants. In contrast, B-cell reactivit y is increased following in vivo injection of MAM, as evidenced by enh anced antibody responses to sheep red blood cells and ovalbumin. Also, there is a marked decrease in the ability of splenocytes from MAM-inj ected mice to produce interleukin-2 (IL-2) but a marked increase in th eir ability to produce IL-4 and IL-6. The combined results suggest tha t MAM induces a lymphokine profile that favors activation of B-cell fu nctions, with a resulting potential for triggering of autoimmune disea se.