Activation of Complement by Endotoxin

Ovine erythrocytes (E) coated with endotoxin (LPS) from Salmonella typhosa 0901 have been used for characterization of the nature of a pathway by which LPS activates complement (C). E-LPS consumed C in normal guinea-pig serum in a manner identical to that in which C is consumed by LPS, that is, with...

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Bibliographic Details
Published in:The Journal of infectious diseases 1973-07, Vol.128 (Supplement-1), p.S86-S90
Main Authors: Mergenhagen, Stephan E., Snyderman, Ralph, Phillips, Jean K.
Format: Article
Language:English
Subjects:
Animals
Antibodies
Antigens, Bacterial
Cell membranes
Chromatography, Ion Exchange
Coagulation
Complement System Proteins
Endotoxins
Erythrocytes
Globulins
Guinea Pigs
Immunoglobulins
In Vitro Techniques
Lipopolysaccharides
Mast cells
Salmonella typhi
Salmonella typhi - pathogenicity
Session II: Immunology
Sheep
Sheep - immunology
Virulence
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Summary:Ovine erythrocytes (E) coated with endotoxin (LPS) from Salmonella typhosa 0901 have been used for characterization of the nature of a pathway by which LPS activates complement (C). E-LPS consumed C in normal guinea-pig serum in a manner identical to that in which C is consumed by LPS, that is, with marked consumption of C3–C9 and little depletion of C1, C4, and C2. A “natural” γ2-globulin, isolated from serum by ion-exchange chromatography, was required for C-mediated lysis of E-LPS in dilute serum. When it was reacted with guinea-pig γ2-globulin, Cl , C4, and C2, followed by C-EDTA, E-LPS was lysed. Deletion of γ2-globulin, Cl, C4, or C2 from the reaction prevented lysis. The small amounts of the early-acting components of C used indicated that it would be difficult to measure their loss in whole serum after incubation with LPS. This hypothesis could explain the earlier findings of a relative sparing of C1, C4, and C2 during consumption of C3–C9 by LPS in normal serum. Our present concepts of C activation by LPS must consider two pathways: a conventional pathway involving “natural” antibody (γ2-globulin) and the formation of the C3 convertase (C4̅2̅) and an alternate pathway involving the formation of a C3 activator, which proceeds without obvious participation of Cl, C4, or C2. The significance of either or both of these pathways to the induction of tissue injury by endotoxin awaits further investigation.
ISSN:0022-1899
1537-6613
DOI:10.1093/infdis/128.Supplement_1.S86