title: Complement receptors CD21/35 link innate and protective immunity during Streptococcus pneumoniae infection by regulating IgG3 antibody responses.
abstract: The CD21/35 receptor provides an important link between innate and adaptive immunity. Its importance during protective immune responses to encapsulated extracellular bacteria was assessed using a new line of mice completely deficient in CD21/35 expression (CD21/35(-/-)). CD21/35 expression was essential for the rapid trapping of C3dg-antigen complexes by B cells in vivo, especially in splenic marginal zones. Despite normal B cell development in CD21/35(-/-) mice, T cell-independent and -dependent antibody responses to low-dose antigens were significantly decreased, with a striking impairment in IgG3 responses. Accordingly, CD21/35(-/-) mice were more susceptible to acute lethal Streptococcus pneumoniae infection. Thus, CD21/35 expression is critical for early protective antibody responses to lethal pathogens that rapidly multiply and quickly overwhelm the immune system.
authors.affiliation: Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Haas
authors.forename: Minoru
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Steeber
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Poe
authors.forename: Mark D
authors.initials: MD
authors.lastname: Zabel
authors.forename: Cheryl B
authors.initials: CB
authors.lastname: Bock
authors.forename: David R
authors.initials: DR
authors.lastname: Karp
authors.forename: David E
authors.initials: DE
authors.lastname: Briles
authors.forename: John H
authors.initials: JH
authors.lastname: Weis
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Tedder
mesh_terms: D000818:Animals; D004198:Disease Susceptibility / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology; D007109:Immunity / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D051379:Mice; D011008:Pneumococcal Infections / Q000235:genetics / Q000276:immunology*; D017463:Receptors, Complement 3b / Q000235:genetics / Q000276:immunology*; D017464:Receptors, Complement 3d / Q000235:genetics / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D017463:Receptors, Complement 3b; D017464:Receptors, Complement 3d