Recognition of pre-processed endogenous antigen by class I but not class II MHC-restricted T cells.
Class I and class II MHC-restricted T lymphocytes recognize non-native forms of antigen. The presentation of antigen to these two classes of T lymphocytes can occur through distinct pathways. Several mechanisms, including differences in antigen processing in different intracellular compartments, have been proposed to account for these pathway differences. Here we describe a T-cell epitope located on the influenza virus haemaglutinin, which is recognized by both class I and class II MHC-restricted cytolytic T lymphocytes (CTL). When expressed de novo in target cells, from a synthetic minigene encoding only the epitope, this pre-processed antigenic site is recognized by class I but not class II MHC-restricted T lymphocytes, even though target cells treated with the exogenously introduced peptide can be recognized by both classes of T cells. Because endogenous expression of the pre-processed antigenic fragment results in differential presentation to class I and class II MHC-restricted CTL, differences between the two different pathways of presentation could lie not at the level of processing but at the level of targeting and/or interaction of processed antigen with MHC.
Sweetser
M T
MT
Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110.
Morrison
L A
LA
Braciale
V L
VL
Braciale
T J
TJ
D000595:Amino Acid Sequence; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D003001:Cloning, Molecular; D000939:Epitopes; D006183:H-2 Antigens / Q000276:immunology*; D006389:Hemagglutinins, Viral / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D009980:Influenza A virus / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*
D000939:Epitopes; D006183:H-2 Antigens; D006389:Hemagglutinins, Viral; D000949:Histocompatibility Antigens Class II; D009842:Oligopeptides; D011948:Receptors, Antigen, T-Cell