Trogocytosis efficiency is dependent upon TCR affinity for MHC: Peptide ligands (APP4P.115)

Abstract

Abstract Antigen recognition by CD4+ T cells leads to large-scale spatial and temporal molecular redistributions, forming the immunological synapse. We have previously shown that upon dissociation from APC, T cells capture large membrane fragments from the antigen presenting cell containing both MHC:peptide ligands and costimulatory molecules directly from the immunological synapse in a process termed trogocytosis. The transferred molecules are retained on the surface of the T cell and sustain intracellular signaling and are associated with the selective survival of the trogocytosis positive cells after removal of the antigen presenting cells. To further characterize trogocytosis, we have examined the impact of TCR affinity for cognate MHC:peptide ligands on the efficiency of trogocytosis. Using moth cytochrome C 88-103 and the altered peptide ligands MCC K99A and MCC-A, we show here that the extent of trogocytosis by primary murine CD4+ T cells correlates with the affinity of the TCR for the MHC:peptide ligands. Preliminary studies also show that sustained intracellular signaling and selective survival of the trogocytosis+ cells varies based upon the TCR affinity for the specific MHC:peptide ligands captured by the T cell.