title: Competition between MHC class I alleles for cell surface expression alters CTL responses to influenza A virus.
abstract: Mammalian cells express up to six different MHC class I alleles, many of which differ in terms of their interaction with components of the Ag presentation pathway and level of cell surface expression. However, it is often assumed in Ag presentation studies that class I alleles function independently of each other. We have compared cell surface expression levels and function of MHC class I molecules in F(1) hybrid mice with those in the homozygous parental strains. The level of cell surface expression of certain alleles in F(1) mice differed significantly from 50% of that found on the same cell type in the corresponding parental strain, suggesting allele-specific competition for cell surface expression, and not expression solely according to gene dosage. The strongest effect was observed in H-2(b) x H-2(k) F(1) mice, in which the H-2(b) class I molecules dominated over the H-2(k) class I molecules. The magnitude of H-2(k)-restricted CTL responses to influenza A virus infection was similar in the F(1) hybrid and parental H-2(k) mice. However, in H-2(k) mice expressing a K(b) transgene, cell surface levels of the endogenous class I molecules were down-regulated to a greater degree than in F(1) hybrid mice, and H-2(k)-restricted CTL responses against influenza A virus were greatly reduced, although the CTL repertoire was apparently present. Therefore, certain MHC class I molecules compete with each other for cell surface expression, and the resulting low cell surface expression of specific alleles can lead to a severe reduction in the ability to generate a CTL response.
authors.affiliation: Department of Immunology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Tourdot
authors.forename: Keith G
authors.initials: KG
authors.lastname: Gould
mesh_terms: D000483:Alleles; D000818:Animals; D001667:Binding, Competitive / Q000235:genetics / Q000276:immunology; D002462:Cell Membrane / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D003433:Crosses, Genetic; D003602:Cytotoxicity, Immunologic / Q000235:genetics*; D004306:Dose-Response Relationship, Immunologic; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D005260:Female; D018628:Gene Dosage; D005786:Gene Expression Regulation / Q000276:immunology*; D006183:H-2 Antigens / Q000096:biosynthesis / Q000235:genetics; D064532:Histocompatibility Antigen H-2D; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000235:genetics*; D009980:Influenza A virus / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008822:Mice, Transgenic; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism
chemical_list: D006183:H-2 Antigens; C024755:H-2K(K) antigen; C032876:H-2Kb protein, mouse; D064532:Histocompatibility Antigen H-2D; D015395:Histocompatibility Antigens Class I