T-cell subsets regulating anti-acetylcholine-receptor-antibody formation in myasthenia gravis and characterization of suppressor T-cell factors involved.

The in vitro generation of anti-acetylcholine-receptor (AChR)-antibody-forming cells from B cells of myasthenia gravis (MG) patients occurred only in the presence of OKT4+ cells. Anti-AChR-antibody formation by lymphocytes from MG patients was suppressed by normal T cells, and the requirement of both OKT4+ and OKT8+ cells was suggested for this suppression. Culture supernatant from normal T cells stimulated with excess doses of AChR antigen, but not T cells from patients, suppressed anti-AChR-antibody formation by lymphocytes from patients. The fraction of the culture supernatant with molecular weight of 45,000 to 67,000 seemed to contain an AChR-antigen-specific and antigen-binding suppressor factor with some allogeneic barrier, while the fraction with a molecular weight of 10,000 to 28,000 contained the antigen-nonspecific factor.