T lymphocyte recognition of acetylcholine receptor: Localization of the full T cell recognition profile on the extracellular part of the α chain of Torpedo californica acetylcholine receptor

A series of eighteen consecutive overlapping synthetic peptides, of uniform size and overlaps, which encompass the entire extracellular part (residues 1–210) of the Torpedo californica acetylcholine receptor α chain were examined in vitro for their ability to stimulate lymph node cells from acetylcholine receptor‐primed C57BL/6 (H‐2b), C3H/He (H‐2k), SWR (H‐2q) and SJL (H‐2s) mice. The recognition sites (T sites) by acetylcholine receptor‐primed lymph node cells from these mouse strains resided within six regions on the extracellular part of the α chain. Three of the regions recognized by T cells conincided with regions recognized by antibodies (i.e. B cells) and one of these three regions also coincided with an a‐neurotoxin‐binding region. It is noteworthy that, in addition to sites recognized by both T and B cells, the protein has at least two sites which are recognized exclusively by T cells and to which no detectable antibody responses are directed.