Individual clones of carrier-specific T cells help idiotypically and isotypically heterogeneous anti-hapten B-cell responses.

We have established lines and clones of helper T cells specific for the antigen fowl gamma globulin (FGG) and maintained these cells in continuous proliferation in vitro for up to 8 months. During this period the specific helper activity was assessed in vitro in T cell-dependent anti-hapten responses. These pure populations of FGG-specific helper T cells provide help in the absence of other T cells for the induction of B cells to produce specific antibody of different isotypes and idiotypes. The same clones of specific helper T cells can provide help for a T cell-dependent antibody response against azobenzene arsonate (ARS), dinitrophenol (DNP) or phosphorylcholine (PC). With the exception of one clone all FGG-specific helper T cells (TFGG) promoted anti-hapten responses only when the hapten was covalently bound to the specific carrier. Help was only provided when T cells and T-depleted spleen cells were H-2 compatible to the left of the I-B region.