Antigen-T Lymphocyte Interactions in the Induction of Functional Unresponsiveness

Abstract

In the initiation of an immune response helper/inducer T lymphocytes are activated by antigen presented in association with Class II major histocompatibility complex (MHC) gene products^1,2 Even though there is now extensive information on the structure of both MHC Class II determinants^3,4 and the T cell receptor^5,6 their physical interaction with antigen in the induction of an activation signal is unclear. As a preliminary step in the analysis of receptor antigen interactions it is necessary to demonstrate specific binding of that ligand to the appropriate receptor. Recently employing T lymphocyte clones reactive with defined antigens the specific binding to T cells of antigen in the presence of antigen presenting cells⁷ or in isolation^8,9 has been reported. We have isolated human T lymphocyte clones reactive with a 24 amino acid peptide (p20) located at the carboxyl terminus (306–329) of the HA-1 molecule of influenza virus haemagglutinin (HA)¹⁰, that after incubation with a supraimmunogenic concentration of p20 in the absence of presenting cells fail to respond to an immunogenic challenge¹¹.