title: Mouse B-1 cell-derived mononuclear phagocyte, a novel cellular component of acute non-specific inflammatory exudate.
abstract: At least three B cell subsets, B-1a, B-1b and B-2, or conventional B cells are present in the mouse periphery. Here we demonstrate that B-1 cells spontaneously proliferate in stationary cultures of normal adherent mouse peritoneal cells. B-1 cells were characterized by morphology, immunohistochemistry and flow cytometry. IgM was detected in the supernatants of these cultures. We demonstrated that the major cell population analyzed expresses the B-1b phenotype. When these cells were transferred to a new culture, a large proportion of them adhere to the plastic surface, and spread as bipolar cells endowed with the capacity to phagocytose via Fc and mannose receptors. Flow cytometry analysis of these adherent cells demonstrated that the great majority of them share both B-220 and Mac-1 antigens. Nevertheless, 45% of them were exclusively Mac-1(+). Finally, when they were labeled in vitro with [(3)H]thymidine and transferred to the peritoneal cavity of naive mice, they migrate to a non-specific inflammatory focus induced by a foreign-body implant. These data demonstrate that B-1 cells, mainly B-1b cells, not only proliferate and differentiate into a mononuclear phagocyte in vitro, but also that they exit the peritoneal cavity and migrate to a non-specific inflammatory milieu.
authors.affiliation: Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, and Center of Electron Microscopy, Federal University of São Paulo, Rua Botucatu 862, 04023-9000, São Paulo, Brazil.
authors.forename: S R
authors.initials: SR
authors.lastname: Almeida
authors.forename: L S
authors.initials: LS
authors.lastname: Aroeira
authors.forename: E
authors.initials: E
authors.lastname: Frymuller
authors.forename: M A
authors.initials: MA
authors.lastname: Dias
authors.forename: C S
authors.initials: CS
authors.lastname: Bogsan
authors.forename: J D
authors.initials: JD
authors.lastname: Lopes
authors.forename: M
authors.initials: M
authors.lastname: Mariano
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000166:cytology* / Q000276:immunology*; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D002448:Cell Adhesion; D002455:Cell Division; D002465:Cell Movement; D002478:Cells, Cultured; D005260:Female; D007075:Immunoglobulin M / Q000096:biosynthesis; D007249:Inflammation / Q000276:immunology / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D010586:Phagocytes / Q000166:cytology / Q000276:immunology*; D011836:Radiation Tolerance
chemical_list: D007075:Immunoglobulin M