The requirement of specific anticapsular IgG for killing of Haemophilus influenzae by the alternative pathway of complement activation.


Journal Article

Employing an in vitro bactericidal assay using C4-deficient guinea pig serum (C4D-GPS), we evaluated the ability of the alternative pathway to kill a number of strains of encapsulated and unencapsulated Haemophilus influenzae (HI). Complement activation occurred, but no bactericidal activity was observed against any of the tested HI in nonimmune C4D-GPS without detectable antibody to HI-type b (HIb) capsular polysaccharide (HIb-ps). In the presence of high-titered human anti- (type b) IgG, C4D-GPS killed the encapsulated strains. Restoration of classical pathway activity by the addition of purified C4 to C4D-GPS, which contained antibody to somatic antigens, resulted in killing of some strains of both encapsulated and unencapsulated HI. In nonimmune C4D-GPS the alternative pathway is activated but does not mediate bactericidal activity. The addition of specific high-titered anticapsular IgG results in killing of encapsulated HI by the alternative pathway in guinea pig serum.

Full Text

Cited Authors

  • Tarr, PI; Hosea, SW; Brown, EJ; Schneerson, R; Sutton, A; Frank, MM

Published Date

  • April 1982

Published In

Volume / Issue

  • 128 / 4

Start / End Page

  • 1772 - 1775

PubMed ID

  • 6977569

Pubmed Central ID

  • 6977569

International Standard Serial Number (ISSN)

  • 0022-1767


  • eng

Conference Location

  • United States