Participation of immunoglobulin and the alternative complement pathway in opsonization of Bacteroides fragilis and Bacteroides thetaiotaomicron

The Journal of Infectious Diseases
A B Bjornson, H S Bjornson

Abstract

Studies were conducted to determine the requirements for immunoglobulin and complement for opsonization of Bacteroides fragilis and Bacteroides thetaiotaomicron. The ability of human sera depleted of immunoglobulin or complement components to promote phagocytosis and intracellular killing of the strains of Bacteroides by human leukocytes was measured in vitro under anaerobic conditions. Neither hypogammaglobulinemic sera nor pooled normal human serum (PNHS) heated at 56 C for 30 min supported phagocytosis and killing of the strains of Bacteroides. Sera depleted of terminal complement components by treatment with inulin or cobra venom factor and C8-deficient human serum did not support phagocytosis of the test strains. PNHS depleted of C3, factor B, or factor D also did not support phagocytosis of either strain. Dose-dependent restoration of the opsonic activity of factor B-depleted serum was accomplished by purified human factor B but not by human C2. The results indicated that immunoglobulin and components of the alternative complement pathway participate in opsonization of the strains of Bacteroides tested in this study.

Citations

Mar 1, 1987·The Journal of Experimental Medicine·A B BjornsonH S Bjornson

Related Concepts

Hypogammaglobulinemia
Metazoa
Bacteroides
Bacteroides fragilis
Complement Pathway, Alternative
Complement 2
Complement C4, Precursor
Complement component C6
Complement Component C8 gamma
Cavia porcellus

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