A monoclonal antibody that appears to recognize the receptor for human T-cell growth factor; partial characterization of the receptor.

Abstract

T-cell growth factor (TCGF or interleukin-2) is an inducible glycoprotein hormone of molecular weight 15,000 (ref. 1) synthesized and secreted by T lymphocytes following activation with antigen or mitogen2,3. TCGF is required for proliferation and expansion of T cells following antigen encounter4,5 and to maintain them in long-term culture in vitro6–9. Full expression of the human immune response requires both the induction of TCGF synthesis and the formation of specific TCGF membrane receptors10,11. Monoclonal antibodies binding TCGF have been prepared12,13. In contrast, antibodies specific for the TCGF membrane receptor have not been identified, nor has the receptor been characterized. We have prepared a monoclonal antibody, termed anti-Tac14,15, which appears to bind to the human membrane receptor for TCGF. In support of this, we now demonstrate that anti-Tac suppresses TCGF induced proliferation of T cells and blocks binding of radiolabelled TCGF to cells from a cloned human continuous T-cell line. Also we have partially purified and characterized the putative TCGF receptor. This receptor is a glycoprotein with a molecular weight (Mr) of 47,000–53,000.