This application is designed to study various properties of T cell receptors. We will concentrate on those receptors which recognize antigen in association with major histocompatibility complex (MHC) products (antigen/H-2) in the mouse. Our ultimate goals are to identify and isolate the molecule(s) responsibile for this recognition and to map them genetically. We will be greatly helped in these studies by the recent development in our laboratory of techniques for preparing cloned ?T cell hybridomas which recognize antigen/H-2 products. These hybridomas grow continuously and rapidly in normal tissue culture medium. When confronted with the appropriate antigen/H-2 combination, however, they secrete interleukin-2. They also bind to antigen-pulsed presenting cells of the appropriate H-2 haplotype. Attempts will be made to characterize the antigen/H-2 receptor(s) immunochemically and biochemically. Immunochemical analysis will include studies on antisera and B hybridomas raised against the T cell hybridomas, with particular emphasis on those which block antigen binding. Biochemical analysis will include attempts to isolate antigen and/or H-2 binding material from radiolabelled cells. In collaboration with Dr. Hood we will investigate the expression of Ig heavy-like mRNA in these cells. Phosphoryl choline (PC)-reactive hybridomas will be made to check the status of VH genes and mRNA coding for PC-binding heavy chains. In collaborative studies with Dr. Riblet we will prepare hybrids which can be used for analysis of heavy, kappa and lambda gene rearrangements. Somatic cell genetics will be used to establish which chromosomes code for the T cell receptor(s) for antigen/H-2. T cell hybridomas will be prepared using antigen specific parental T cells with marked chromosomes, and in sublines which retain or have lost antigen specificity the coincidence of specificity and the marked chromosomes will be noted. In addition, in collaboration with Dr. Francke, antigen non-reactive variants of already existing hybridomas will be analyzed for chromosome loss.