title: New insights into heterogeneity of peritoneal B-1a cells.
abstract: Peritoneal B-1a cells are characterized by their expression of CD5 and enrichment for germline-encoded IgM B cell receptors. Early studies showing expression of a diverse array of VDJ sequences among purified B-1a cells provided a molecular basis for understanding the heterogeneity of the B-1a cell repertoire. Antigen-driven positive selection and the identification of B-1a specific progenitors suggest multiple origins of B-1a cells. The introduction of new markers such as PD-L2, CD25, CD73, and PC1 (plasma cell alloantigen 1, also known as ectonucleotide phosphodiesterase/pyrophosphatase 1) further helped to identify phenotypically and functionally distinct B-1a subsets. Among many B-1a subsets defined by these new markers, PC1 is unique in that it subdivides B-1a cells into PC1(hi) and PC1(lo) subpopulations with distinct functions, such as production of natural IgM and gut IgA, response to the pneumococcal antigen PPS-3, secretion of interleukin-10, and support for T helper 1 (TH 1) cell differentiation. RNA sequencing of these subsets revealed differential expression of genes involved in cellular movement and immune cell trafficking. We will discuss these new insights underlying the heterogeneous nature of the B-1a cell repertoire.
authors.affiliation: The Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Wang
authors.affiliation: Laboratory of Molecular Immunology and Immunology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Jian-xin
authors.initials: JX
authors.lastname: Lin
authors.affiliation: Laboratory of Molecular Immunology and Immunology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: Malaria Infection Biology and Immunity Unit, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
authors.forename: Jeff
authors.initials: J
authors.lastname: Skinner
authors.affiliation: Laboratory of Molecular Immunology and Immunology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Leonard
authors.affiliation: The Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
authors.forename: Herbert C
authors.initials: HC
authors.lastname: Morse
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000166:cytology* / Q000502:physiology*; D016175:B-Lymphocyte Subsets / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D018740:Genetic Heterogeneity; D006801:Humans
keywords: B-1a; IL-10; PC1; lymphocyte trafficking