PMID- 2467938
OWN - NLM
STAT- MEDLINE
DCOM- 19890522
LR  - 20210514
IS  - 0022-1767 (Print)
IS  - 0022-1767 (Linking)
VI  - 142
IP  - 8
DP  - 1989 Apr 15
TI  - Analysis of the mechanism of recognition in the complement alternative pathway 
      using C3b-bound low molecular weight polysaccharides.
PG  - 2759-65
AB  - The human complement (C) system recognizes bacterial, fungal and viral activators 
      of the alternative pathway following covalent attachment of the protein C3b to 
      carbohydrates (CHO) on the surface of the organisms. Recognition first manifests 
      itself as a 3- to 10-fold reduction in the affinity of C3b for factor H, a 
      regulatory protein of C. This report describes the use of a fluorimetric assay 
      which is sensitive to the C3b-H interaction to study the characteristics of 
      recognition. Fluid phase C3b covalently bound to CHO (C3b-CHO) was prepared by 
      activating C3 in the presence of the small homopolymers dextran (alpha 1-6 
      polyglucose) or inulin (beta 1-2 polyfructose). In particulate form both 
      polysaccharides are activators of C. The conjugates exhibited increased 
      resistance to inactivation in the factor H-dependent assays compared to C3b not 
      bound to CHO and to C3b bound to mono- or disaccharides. The dextran-induced 
      restriction of inactivation was partially reversed by treatment of the conjugate 
      with dextranase. C3b-CHO conjugates failed to bind to factor H-Sepharose and when 
      introduced into serum behaved as though C3b was attached to particulate 
      activators of C, suggesting that the fluorimetric assay accurately reports 
      recognition. The results suggest that the recognition site which induces a 
      reduction in the affinity of C3b for factor H is distinct from the thioester site 
      of C3b and can recognize structural features of polysaccharides including size, 
      sialic acid content, and possibly aspects of three-dimensional oligosaccharide 
      structure.
FAU - Pangburn, M K
AU  - Pangburn MK
AD  - Department of Biochemistry, University of Texas Health Center, Tyler 75710.
LA  - eng
GR  - DK-35081/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Immunol
JT  - Journal of immunology (Baltimore, Md. : 1950)
JID - 2985117R
RN  - 0 (CFH protein, human)
RN  - 0 (Complement C3b Inactivator Proteins)
RN  - 0 (Dextrans)
RN  - 0 (Polysaccharides)
RN  - 80295-43-8 (Complement C3b)
RN  - 80295-65-4 (Complement Factor H)
RN  - 9005-80-5 (Inulin)
RN  - EC 3.2.1.11 (Dextranase)
SB  - IM
MH  - Binding Sites
MH  - Chromatography, Affinity
MH  - *Complement Activation
MH  - Complement C3b/*metabolism
MH  - Complement C3b Inactivator Proteins/metabolism
MH  - Complement Factor H
MH  - *Complement Pathway, Alternative
MH  - Dextranase/pharmacology
MH  - Dextrans/metabolism
MH  - Humans
MH  - Inulin/pharmacology
MH  - Molecular Weight
MH  - Polysaccharides/*metabolism
EDAT- 1989/04/15 00:00
MHDA- 1989/04/15 00:01
CRDT- 1989/04/15 00:00
PHST- 1989/04/15 00:00 [pubmed]
PHST- 1989/04/15 00:01 [medline]
PHST- 1989/04/15 00:00 [entrez]
PST - ppublish
SO  - J Immunol. 1989 Apr 15;142(8):2759-65.