T Cell Recognition of Antigen Recognize antigen peptide fragments bound to specialize cell surface molecules on antigen-presenting cells (APC). Molecules are encoded by major histocompatibility complex Peptides are displayed to T cells as peptide:MHC complexes T cell antigen receptors recognize peptide:MHC complexes Each MHC molecule can bind numerous different peptides Two classes of MHC moleculesT Cell Recognition of Antigen ◼ Recognize antigen peptide fragments bound to specialize cell surface molecules on antigen-presenting cells (APC). ◼ Molecules are encoded by major histocompatibility complex ◼ Peptides are displayed to T cells as peptide:MHC complexes ◼ T cell antigen receptors recognize peptide:MHC complexes ◼ Each MHC molecule can bind numerous different peptides ◼ Two classes of MHC molecules