immune system process antigen processing and presentation GO:0019882 GO:0030333 The process in which an antigen-presenting cell expresses antigen (peptide or lipid) on its cell surface in association with an MHC protein complex. This term was improved by GO_REF:0000022. It was renamed and redefined. Wikipedia:Antigen_presentation antigen presentation antigen processing biological_process go.owl obi.owl