title: Antibodies to acetylcholine receptor and tetanus toxoid: in vitro synthesis by thymic lymphocytes.
abstract: Thymic lymphocytes (TL) of patients with myasthenia gravis (MG) have been reported to synthesize antibodies to acetylcholine receptors (anti-AChR). Incubation of TL with pokeweed mitogen (PWM), a polyclonal T cell- and monocyte-dependent activator of B cell differentiation, was reported to inhibit TL in vitro synthesis of anti-AChR. We studied the TL of 16 patients with MG without thymoma. TL of 10 of 16 patients synthesized anti-AChR in vitro without stimulation. In the presence of PWM, the amount of anti-AChR synthesized by the TL of these 10 patients increased in five, decreased in three, and was unaffected in two. There was a correlation between serum anti-AChR titer and PWM-stimulated synthesis (r = 0.87), but not with unstimulated synthesis (r = 0.33) of anti-AChR by TL. There was no correlation between the amount of synthesized anti-AChR and the amount of secreted IgG or with the percentage of B cells (surface Ig+) in the TL suspensions. TL of three age-matched cardiac surgery controls failed to synthesize detectable anti-AChR, although two of three synthesized IgG. Four patients with MG were booster immunized with tetanus toxoid (TT) 3 to 4 wk prior to thymectomy. TL of three synthesized anti-TT in vitro, whereas TL of three nonboosted MG patients failed to synthesize anti-TT. Thus, we have shown that TL of some patients with MG are capable of anti-AChR synthesis, with evidence of heterogeneity of the in vitro response, and the B cell repertoire in the thymus may, in part, reflect recent systemic immune events of the host.
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D001323:Autoantibodies / Q000096:biosynthesis*; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000276:immunology / Q000473:pathology; D011950:Receptors, Cholinergic / Q000276:immunology*; D013601:T-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D013745:Tetanus Toxoid / Q000276:immunology*; D013950:Thymus Gland / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial; D001323:Autoantibodies; D007074:Immunoglobulin G; D011950:Receptors, Cholinergic; D013745:Tetanus Toxoid