(427f) Identification of T Cell Antigens Using Surface Display

Treatment of a number of human diseases, particularly autoimmune disorders, would benefit from the identification of antigens known to activate T cells. A system to identify CD4+ T cell-activating peptides from a combinatorial library is being developed. First, a model system using the hemagglutinin 307-319 peptide antigen and a cognate T cell hybridoma is being tested. Using microbial surface display, the peptide is delivered to antigen presenting cells (APCs) through phagocytosis. Peptide display is validated by flow cytometry. The surface peptide is engineered to be selectively processed and presented by class II MHC, which will in turn activate antigen-specific CD4+ T cells. Preliminary results indicate that T cell stimulation by peptide delivery to macrophages and dendritic cells is feasible; attempts to screen mock peptide libraries to identify a known T cell antigen are ongoing.