title: Plasma cell alloantigen ENPP1 is expressed by a subset of human B cells with potential regulatory functions.
abstract: Plasma cell alloantigen 1 (PC1), also known as ENPP1 (ectonucleotide pyrophosphatase/phosphodiesterase 1), is an enzyme involved primarily in hydrolysis of adenosine triphosphate at the cell surface. Although the expression pattern of PC1 is relatively broad, its expression in B cells is found at significant levels only in terminally differentiated germinal center B cells, plasma cells and a subset of B-1a cells in mice. Here we describe studies designed to determine whether expression of PC1 might define novel populations of human B cells with similarities to mouse B cells. We found that PC1 is expressed in small populations of human B lineage cells in peripheral blood, cord blood, tonsils, bone marrow and pediatric peritoneal fluid, with the highest levels in plasma cells. The characteristics of human PC1(+) B cells differ from mouse peritoneal B-1a subsets and from features of the human CD20(+)CD27(+)CD43(+)CD70(-) B-cell subset proposed to be human B-1 cells. Expression of PC1 was greatly increased in B cells stimulated with the combination of CD40 ligand, interleukin (IL)-4 and IL-21. In addition, PC1(+) B cells activated CD4(+) T regulatory cells. ENPP1 thus defines a subset of human B cells that differs significantly from mouse peritoneal B-1a and proposed human B-1 cells.
authors.affiliation: Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
authors.forename: Jeongheon
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
authors.forename: Yong Chan
authors.initials: YC
authors.lastname: Kim
authors.affiliation: Herman B Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Momoko
authors.initials: M
authors.lastname: Yoshimoto
authors.affiliation: Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
authors.forename: Sadia
authors.initials: S
authors.lastname: Abbasi
authors.affiliation: Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
authors.forename: Herbert C
authors.initials: HC
authors.lastname: Morse Iii
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology; D060151:B-Lymphocytes, Regulatory / Q000276:immunology*; D002451:Cell Compartmentation; D049109:Cell Proliferation; D006801:Humans; D007519:Isoantigens / Q000378:metabolism*; D051379:Mice; D008875:Middle Aged; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D010950:Plasma Cells / Q000201:enzymology*; D011755:Pyrophosphatases / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology; D055815:Young Adult
chemical_list: D007519:Isoantigens; D010727:Phosphoric Diester Hydrolases; C065962:ectonucleotide pyrophosphatase phosphodiesterase 1; D011755:Pyrophosphatases