9317543 Nieto The Major Histocompatibility Complex (MHC) class I transplantation antigens function as restriction elements for the presentation of viral and foreign antigens to the T cell receptor. Antigen is presented to the T cell receptor in the form of a peptide which binds within the helical bordered cleft of the class I molecule. The molecular interactions involved in the presentation of the peptide receptor are not fully understood. Preliminary results suggest that the class I molecule is structurally flexible and susceptible to structural perturbations induced by beta-2 microglobulin, a 12 Kd protein non-covalently associated with class I at the cell surface. This research is designed to address the role of class I structural flexibility and the relationship it has to class I function. Specifically, the role of beta-2 microglobulin in overall class I structure and function will be investigated. Discerning the role of beta-2 microglobulin in class I structure will provide insight into the ability of class I to bind and present a vast array of disparate antigenic peptides to the T cell receptor. %%% The transplantation antigens were first shown to be responsible for rejection of tissue transplants in mice. The transplantation antigens are cell surface protein molecules encoded by a multigene complex known as the Major Histocompatibility Complex (MHC). The major gene families in this complex have been designated class I, II, and III. Products of the genes are now known to play a crucial role in the recognition by the immune system of cells bearing foreign antigens on their surfaces. The subject of this research is how the structure of the Class I molecule and an associated protein, known as beta-2 microglobulin, affect their function in recognizing foreign molecules. This research will be carried out by a new investigator at a predominantly undergraduate institution. This research, therefore will not only contribute to our understanding of rec ognition and response mechanisms in immune function, but also enrich the environment for science education at an institution with a high proportion of minority undergraduates. ***
