title: The cellular compartmentalization of macrophage-associated nominal antigen: immunologically relevant macrophage-associated antigen may not require an intracellular phase of macrophage handling.
abstract: It has been hypothesized that internalization and "processing" of the nominal antigen by antigen-presenting cells may be a mandatory event in antigen handling prior to cell surface presentation of the immunologically relevant moiety to T lymphocytes. In previous functional and immunochemical analyses of macrophage (M phi)-associated nominal antigen, we obtained data strongly suggesting that an immunologically relevant pool of antigen was detectable on the surface of M phi pulsed with a soluble protein antigen and then aged for 3-24 h. To provide further information about requisite events of M phi antigen handling, we have attempted to this study to determine the origin of the nominal antigen associated with the surface of the pulsed-aged cell using the terpolymer L-glutamic acid, L-lysine, L-tyrosine (GLT) as the antigen. The surface-bound GLT, after a 24-h culture, appeared to be derived from GLT initially surface-associated after the pulse. No evidence was obtained to support the notion that a significant quantity of GLT, initially internalized after the pulse exposure, was recompartmentalized to the cell surface. The turnover of cell-surface GLT resembled the turnover of M phi membrane proteins in general. These results, therefore, imply that the crucial events of M phi antigen handling of GLT may entirely be a cell surface phenomenon.
mesh_terms: D000818:Animals; D000937:Antigen-Antibody Reactions; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D006168:Guinea Pigs; D007111:Immunity, Cellular; D007700:Kinetics; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D011817:Rabbits
chemical_list: D000954:Antigens, Surface; D010455:Peptides