Complement receptors CD21/35 link innate and protective immunity during Streptococcus pneumoniae infection by regulating IgG3 antibody responses

Immunity. 2002 Dec;17(6):713-23. doi: 10.1016/s1074-7613(02)00483-1.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Disease Susceptibility / immunology
  • Gene Expression Regulation / immunology
  • Immunity / genetics
  • Immunity, Innate / genetics
  • Immunoglobulin G / biosynthesis
  • Immunoglobulin G / genetics
  • Immunoglobulin G / immunology*
  • Mice
  • Pneumococcal Infections / genetics
  • Pneumococcal Infections / immunology*
  • Receptors, Complement 3b / genetics
  • Receptors, Complement 3b / immunology*
  • Receptors, Complement 3d / genetics
  • Receptors, Complement 3d / immunology*
  • Signal Transduction / immunology

Substances

  • Immunoglobulin G
  • Receptors, Complement 3b
  • Receptors, Complement 3d