title: Tolerogenic property of B-1b cells in a model of allergic reaction.
abstract: Since B-1 cells were first described, their origin and function remain controversial. Given the ability to produce natural antibodies and large amounts of IL-10, there is a consensus about their role in innate immunity. More recently, however, B-1 cells have been associated to adaptive immunity as well, due to the demonstration of immunological memory and antigen presentation capability. Here we demonstrate that adoptive transfer of pre-sensitized B-1b cells (obtained from OVA-sensitized mice) to naïve B-1 deficient animals, drastically affects the ability of transplanted animals to mount an adaptive response upon immunization with OVA. In contrast to naïve B-1 populated mice, mice transplanted with sensitized B-1 exhibit lower anti-OVA antibody levels, milder footpad swelling in response to OVA subcutaneous injection and reduced granulomatous reaction to OVA-coated beads. Moreover, we show that these pre-sensitized B-1 cells, when acting as APCs, induce poor T cell proliferation in vitro when compared with macrophages or B-1 cells obtained from naïve mice. This property may be due in part to insufficient expression of the co-stimulatory molecule CD86, necessary for optimal antigen presentation. In conclusion, our data suggest a novel role for B-1 cells as part of suppressor mechanisms in the immune system.
authors.affiliation: Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Beatriz H P
authors.initials: BH
authors.lastname: De Lorenzo
authors.forename: Ronni R N
authors.initials: RR
authors.lastname: Brito
authors.forename: Luiz Claudio
authors.initials: LC
authors.lastname: Godoy
authors.forename: José Daniel
authors.initials: JD
authors.lastname: Lopes
authors.forename: Mario
authors.initials: M
authors.lastname: Mariano
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology* / Q000637:transplantation; D049109:Cell Proliferation; D006967:Hypersensitivity / Q000276:immunology*; D007108:Immune Tolerance; D007110:Immunity, Active; D007113:Immunity, Innate; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D010047:Ovalbumin / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D010047:Ovalbumin