Self peptide/MHC class I complexes have a negligible effect on the response of some CD8+ T cells to foreign antigen.
MHC molecules loaded with self peptides do not trigger a T cell immune response but may deliver signals important for peripheral T cell survival and function. It is unclear if self peptide/MHC complexes on APC in addition can influence the T cell response to co-presented foreign ligands. To address this question, TAP-sufficient and TAP-deficient cells were loaded with ovalbumin peptide (pOVA) to generate APC that present pOVA/H-2Kb complexes in the context of high or low levels of self peptide-loaded MHC class I, respectively. The two cell types were then used to stimulate different CD8+ T cells specific for ovalbumin while the number of presented pOVA/H-2Kb complexes was independently assessed by staining with 25-D1, an antibody against pOVA/H-2Kb. In each case, T cell activation was independent of TAP expression by the APC and depended exclusively on the amount of 25-D1 staining. We conclude that the number of pOVA/Kb complexes and not their frequency relative to self peptide/MHC complexes determines the response of those T cells tested here. These results imply that the repertoire of self peptide/MHC class I complexes presented by APC has a negligible effect on the response of some CD8+ T cells to foreign ligands.
Spörri
Roman
R
Immunobiology Laboratory, Cancer Research UK, London Research Institute, London, GB.
Reis e Sousa
Caetano
C
D000818:Animals; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000502:physiology; D015703:Antigens, CD / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D006183:H-2 Antigens / Q000276:immunology*; D037181:Lectins, C-Type; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D006183:H-2 Antigens; D037181:Lectins, C-Type; D010047:Ovalbumin; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D000099192:CD69 Antigens; C032876:H-2Kb protein, mouse