Lymphokine-like activity of a strain of Mycoplasma arginini

A Mycoplasma arginini strain, found to contaminate a T-T hybridoma designated TUH-14, was the source of a lymphokine-like activity with an ability to stimulate B-blasts to proliferate. Maturation to immunoglobulin secretion induced by the mycoplasma alone was low compared with induction by lipopolysaccharide (LPS), but could reach the same levels achieved with LPS by the addition of a B-cell maturation factor obtained from lectin-activated EL-4 thymoma cells. The mitogenic effect on B-cells was found only in the strain isolated from TUS-14; three other M. arginini strains were negative. Both mitogenic and nonmitogenic mycoplasma membrane preparations displayed higher affinity for B-cells than for T-blasts. However, membranes from the mitogenic strain, the TUH-14 isolate, bound better to activated blasts than to small resting cells, in contrast to the nonmitogenic strain G-230.