title: The two-signal model of lymphocyte activation twenty-one years later.
authors.forename: P
authors.initials: P
authors.lastname: Bretscher
mesh_terms: D000818:Animals; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008954:Models, Biological; D011946:Receptors, Antigen / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D011946:Receptors, Antigen