Immunological effects of IgT synthesized by theta-positive cell lines.

The effects of immunoglobulin (Ig) purified by affinity chromatography from two cultured T cell lines on in vitro immune responses was studied. IgT purified from both EL-4 and WEHI-22 suppressed the thymus-dependent IgM response, but had no effect on the thymus-independent IgM response. In contrast, the IgG responses to both thymus-dependent and independent antigens were augmented at optimal concentrations of IgT. Ig of B cell origin--serum Ig, myeloma Ig, B cell surface Ig -- did not have any of these effects. Because of the similarity of the effects of IgT purified from the lymphomas with the effects of T cells and their IgT, it seems likely that the IgT obtained from EL-4 and WEHI-22 cell lines are analogues of normal IgT and thus should be useful in elucidating some of the chemical and biological properties of IgT.