title: The MHC-related protein 1 (MR1) is expressed by a subpopulation of CD38+, IgA+ cells in the human intestinal mucosa.
abstract: MHC-related 1 (MR1) molecule is a non-classical member of the MHC class I family of proteins. The sequence homology between classical MHC class I molecules and MR1 is very high, although the MR1 gene is not polymorphic and is highly conserved between species. MR1 is the restriction molecule of a sub-population of T lymphocytes, which are CD4-,CD8- and display conserved TCR alpha chain. The function of these cells is currently unknown, but they are believed to have regulatory properties similar to those of the CD1d restricted NKT cells. The MR1 gene is ubiquitously transcribed; however it is unknown what types of cells express the MR1 protein "in vivo". In the present work we analyzed the expression of the MR1 protein using specific antisera and monoclonal antibodies in different human cell lines, in primary cells and in mucosal tissues. We found some lymphoid cell lines that express MR1 on the cell surface but at levels much lower than the MR1 transfected cell lines. In addition, we observed that expression of MR1 in the mucosa is restricted to a subpopulation of plasma cells or plasmablasts, CD38+ or CD138+ and IgA+, located in the human intestinal mucosa. This suggests a function for MR1 in the development of IgA producing plasma cells.
authors.affiliation: Immunology Unit, School of Medicine, Complutense University, Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Gozalbo-López
authors.forename: Manuel
authors.initials: M
authors.lastname: Gómez del Moral
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Campos-Martín
authors.forename: Fernando
authors.initials: F
authors.lastname: Setién
authors.forename: Paloma
authors.initials: P
authors.lastname: Martín
authors.forename: Carmen
authors.initials: C
authors.lastname: Bellas
authors.forename: José R
authors.initials: JR
authors.lastname: Regueiro
authors.forename: Eduardo
authors.initials: E
authors.lastname: Martínez-Naves
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000276:immunology / Q000378:metabolism; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000276:immunology; D006801:Humans; D018928:Immunity, Mucosal / Q000276:immunology*; D007070:Immunoglobulin A / Q000276:immunology / Q000378:metabolism; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D018613:Microscopy, Confocal; D015778:Minor Histocompatibility Antigens; D010950:Plasma Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D016133:Polymerase Chain Reaction
chemical_list: D015395:Histocompatibility Antigens Class I; D007070:Immunoglobulin A; C094840:MR1 protein, human; D015778:Minor Histocompatibility Antigens; D051997:ADP-ribosyl Cyclase 1