In vitro studies on H-2-linked unresponsiveness to synthetic polypeptides. III. Production of an antigen-specific T helper cell factor to (T,G)-A--L.

The in vitro production, assay and partial characterization of an extremely potent antigen-specific T helper cell factor to poly-L-(Tyr, Glu)-poly-DL-Ala--poly-L-Lys [(T,G)-A--L] which may be an important physiological mediator of T cell function in vivo is described. The factor has an antigen-binding site, Ia and Ig-like determinants on the same molecular complex. The response to (T, G)-A--L is under H-2-linked Ir gene control, some but not all low responder haplotypes will produce the factor.