Human lymphocyte production of immunoreactive thyrotropin.

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Abstract
Interferon-.alpha. inducers were previously shown to cause human lymphocyte production of an ACTH-like peptide. TSH was not produced under these conditions. In contrast, this report shows that a T-cell mitogen (staphylococcal enterotoxin A), which does not induce the ACTH-like peptide, caused human lymphocyte production of an immunoreactive (ir) TSH. Lymphocyte synthesis of the ir TSH was first detectable at 24 h, peaked at 48 h, and thereafter declined. NaDodSO4/polyacrylamide gel electrophoresis of intrinsically radiolabeled lymphocyte-derived ir TSH showed radiolabeled peaks at 80, 50 and 26 kilodaltons [kd]. These peaks presumably correspond to trimeric, dimeric and monomeric TSH-like proteins, respectively. Acid treatment and reduction caused the ir TSH to migrate as a 14-kd peak with a 12-kd shoulder in a gel filtration column run in 6 M guanidine hydrochloride. The ir TSH seemed to be composed of subunits with molecular masses corresponding to those of the .beta. and .alpha. chains of human TSH, respectively. The ir TSH appeared to be glycoprotein because it bound to a concanavalin A affinity column. In addition to ACTH, human lymphocytes may also produce a TSH-like substance.