A functioning rat thyroid cell line (FRTL5) was used to study interactions of thyrotropin (TSH) and various cytokines on expression of class I and II major histocompatibility complex (MHC) antigens and on growth stimulation. Only γ-interferon (γ-IFN) affected MHC antigen expression, i.e., to enhance class I. that was constitutive, and to induce class II. A concomitant, but probably not directly related, effect of γ-IFN was to diminish growth stimulation, as effected by TSH and other activators of adenylate cyclase and measured by DNA increase and enhanced incorporation of [3H]thymidine into DNA. Stimulation of growth by tetradecanoylphorbol ester was also decreased by γ-IFN. These effects of γ-IFN were mimicked to some degree by tumor necrosis factor but there was major synergism between the two cytokines. Enhanced accumulation of cAMP by TSH and other agents was not diminished in these experiments. Flow cytometry analysis showed that inhibition of growth stimulation involved blocking of the passage of cells from the g 0 1 phase to the S phase. The data may have relevance to goiter size in autoimmune thyroid disease.
- Class II antigen
- Tumor necrosis factor α
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism