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

P. I. Tarr, S. W. Hosea, E. J. Brown, R. Schneerson, A. Sutton, M. M. Frank

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)1772-1775
Number of pages4
JournalJournal of Immunology
Volume128
Issue number4
StatePublished - May 8 1982
Externally publishedYes

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