The first aim of this research is to examine the primary structure of several T cell antigens which are similar in overall structure to the HLA-A, -B, -C antigens and which may be the human homologues of the murine TL and Qa antigens. The problem will first be approached by purifying each of the antigens by sequential lectin and monoclonal antibody affinity chromatography. Monoclonal antibodies that react with two of these "HLA-like" antigens are available. Using partially purified material as immunogen, monoclonal antibodies will be generated to a Beta2-microglobulin-associated cell surface antigen(s) and to a Beta2-microglobulin-like protein (Betat) for which there are currently no monoclonal antibodies available. The purified molecules will be characterized structurally. The purified antigen will also be employed in functional studies. Such studies may be useful in determining the evolutionary origin of these molecules and may lead to insights into their functional roles. The second aim is to examine the primary structure of some human T cell specific proteins which are present on a human cytotoxic T cell line which specifically recognizes an allogeneic HLA-DR antigen. This problem will be approached by first constructing a cDNA library from the T cell line and then from this library obtaining a sub-library containing only clones which are specific for T cells. These clones will then be correlated with recently identified T cell specific proteins by hybrid selection of mRNA, cell-free translation and immunoprecipitation. Finally, when cDNA clones have been correlated with specific proteins, then DNA sequencing will be carried out in order to obtain amino acid sequence information about the proteins of interest. It is anticipated that one or more of these proteins may be components of the T cell recognition unit ("T cell receptor") for the HLA-DR alloantigen.