[Nonspecific mitogenic factors of Mycoplasma: immunobiological properties].

The readily extractable surface membrane proteins of M. arthritidis and sodium dodecyl sulfate-solubilized membrane components of M. fermentans were found to have the highest mitogenic action on the splenocytes from CBA mice and the least on those from C57BL/6 mice. The M. arthritidis mitogen (MAM) is an antigen-dependent T-cell mitogen that inhibits the specific proliferation of T cells, inducing their non-specific proliferation. Dextran sulfate-induced blockage of lymphocyte proliferation under the action of MAM was stimulated with interleukin-2, which suggests MAM-induced expression of receptors to interleukin-2 onto the surface of lymphocytes. A factor that has the activity of interleukin-1 and stimulates the proliferation of C57BL/6 murine thymocytes with phytohemagglutinin was found to liberate into a culture medium.