title: MHC class I allele dosage alters CD8 expression by intestinal intraepithelial lymphocytes.
abstract: The development of TCR alphabeta(+), CD8alphabeta(+) intestinal intraepithelial lymphocytes (IEL) is dependent on MHC class I molecules expressed in the thymus, while some CD8alphaalpha(+) IEL may arise independently of MHC class I. We examined the influence of MHC I allele dosage on the development CD8(+) T cells in RAG 2(-/-) mice expressing the H-2D(b)-restricted transgenic TCR specific for the male, Smcy-derived H-Y Ag (H-Y TCR). IEL in male mice heterozygous for the restricting (H-2D(b)) and nonrestricting (H-2D(d)) MHC class I alleles (MHC F(1)) were composed of a mixture of CD8alphabeta(+) and CD8alphaalpha(+) T cells, while T cells in the spleen were mostly CD8alphabeta(+). This was unlike IEL in male mice homozygous for H-2D(b), which had predominantly CD8alphaalpha(+) IEL and few mostly CD8(-) T cells in the spleen. Our results demonstrate that deletion of CD8alphabeta(+) cells in H-Y TCR male mice is dependent on two copies of H-2D(b), whereas the generation of CD8alphaalpha(+) IEL requires only one copy. The existence of CD8alphabeta(+) and CD8alphaalpha(+) IEL in MHC F(1) mice suggests that their generation is not mutually exclusive in cells with identical TCR. Furthermore, our data imply that the level of the restricting MHC class I allele determines a threshold for conventional CD8alphabeta(+) T cell selection in the thymus of H-Y TCR-transgenic mice, whereas the development of CD8alphaalpha(+) IEL is dependent on, but less sensitive to, this MHC class I allele.
authors.affiliation: Department of Pediatrics and Beirne B. Carter Center for Immunology, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA.
authors.forename: B S
authors.initials: BS
authors.lastname: Podd
authors.forename: C
authors.initials: C
authors.lastname: Aberg
authors.forename: K L
authors.initials: KL
authors.lastname: Kudla
authors.forename: L
authors.initials: L
authors.lastname: Keene
authors.forename: E
authors.initials: E
authors.lastname: Tobias
authors.forename: V
authors.initials: V
authors.lastname: Camerini
mesh_terms: D000483:Alleles; D000818:Animals; D000940:Antigenic Variation; D016827:CD8 Antigens / Q000235:genetics / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000276:immunology; D005260:Female; D018628:Gene Dosage; D005805:Genes, MHC Class I; D006182:H-Y Antigen / Q000235:genetics / Q000378:metabolism; D006579:Heterozygote; D006720:Homozygote; D007422:Intestines / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000378:metabolism
chemical_list: D016827:CD8 Antigens; D004268:DNA-Binding Proteins; D006182:H-Y Antigen; C499308:Rag2 protein, mouse; D016693:Receptors, Antigen, T-Cell, alpha-beta; C064655:V(D)J recombination activating protein 2