Transforming growth factor-beta (TGF-beta)-resistant helper T lymphocyte clones show a concomitant loss of all three types of TGF-beta receptors.

Abstract

Three ovalbumin-specific T helper cell lines (OVA-7T cells) that differ in their susceptibility to the immunosuppressive effects of transforming growth factor-beta (TGF-beta) were cloned. The frequency of TGF-beta-resistant OVA-7T cell clones correlated with the decline of TGF-beta sensitivity in the original OVA-7T parental cell lines. In TGF-beta-resistant OVA-7T cell clones, TGF-beta inhibited neither the growth of the T cells nor their secretion of granulocyte macrophage CSF. TGF-beta suppressed the expression of c-myc mRNA in OVA-7T-responder but not in OVA-7T-nonresponder cells. TGF-beta resistance was found to be due to a loss of TGF-beta high-affinity binding sites, with an absence of expression of the distinct 54-, 70-, 110-, and 250-kDa surface proteins that bind TGF-beta on TGF-beta-susceptible T cells. Loss of TGF-beta R may enable T cells to escape the negative feedback control provided by TGF-beta secreted from activated T cells during an immune response.