Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2007-10-3
pubmed:abstractText
Childhood malaria caused by Plasmodium falciparum is often characterized by severe anemia at low parasite burdens; the mechanism(s) responsible for this pathology remain to be defined. We have reported, based on clinical observations and in vitro models, that complement control proteins on erythrocytes such as CR1, the immune adherence receptor specific for C3b, may be reduced in childhood malaria, suggesting a possible role for complement in erythrocyte destruction. Intravascular lysis of iE by P. falciparum leads to release of erythrocyte breakdown products such as hemoglobin and hematin, which have inflammatory properties. In the present article, we demonstrate that in serum and in anticoagulated whole blood, moderate concentrations of hematin activate the alternative pathway of complement and promote deposition of C3 activation and breakdown products on erythrocytes. The degree of C3 fragment deposition is directly correlated with erythrocyte CR1 levels, and erythrocytes opsonized with large amounts of C3dg form rosettes with Raji cells, which express CR2, the C3dg receptor which is expressed on several types of B cells in the spleen. Thus, the reaction mediated by hematin promotes opsonization and possible clearance of the youngest (highest CR1) erythrocytes. A mAb specific for C3b, previously demonstrated to inhibit the alternative pathway of complement, completely blocks the C3 fragment deposition reaction. Use of this mAb in nonhuman primate models of malaria may provide insight into mechanisms of erythrocyte destruction and thus aid in the development of targeted therapies based on inhibiting the alternative pathway of complement.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
179
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5543-52
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Hematin promotes complement alternative pathway-mediated deposition of C3 activation fragments on human erythrocytes: potential implications for the pathogenesis of anemia in malaria.
pubmed:affiliation
Department of Biochemistry and Molecular Genetics, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't