Analysis of helper-T-cell function by acetylcholine receptor-reactive cell lines of defined AChR-subunit specificity

A small panel of cloned acetylcholine receptor (AChR)-reactive helper T cells were examined for their ability to proliferate when stimulated with AChR or purified AChR subunits. It was observed that all T-cell lines preferentially responded to the AChR alpha subunit, but that some also were stimulated by other subunits as well. This was interpreted as indicating that the alpha subunit plays a major role in anti-AChR T-cell responses, but that considerable potential cross-reactivity exists among the subunits recognized by T cells. Furthermore, a high level of "microheterogeneity" in the T-cell-specificity repertoire was suggested by the fact that even this small panel of cloned lines expressed several patterns of subunit reactivity. Finally, all cloned T-cell lines examined were found to be capable of functioning as regulatory helpers in vitro by providing the necessary signals to AChR-responsive B cells, resulting in anti-AChR antibody production.