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Reduced Erythrocyte CR1 (CD 35) Receptor Function and Complement Opsonization in Factor I‐Deficient Patients is Restored by Plasma Infusion
Author(s) -
JEPSEN H. H.,
TEISNER B.,
RASMUSSEN J. M.,
SVEHAG S.E.
Publication year - 1989
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1989.tb01122.x
Subject(s) - antibody opsonization , opsonin , complement factor i , complement system , monoclonal antibody , receptor , complement factor b , immune adherence , chemistry , factor h , antibody , immune system , medicine , complement receptor 1 , endocrinology , immunology , biology , biochemistry , hemagglutination
Erythrocytes (E) from three factor I‐deficient patients were investigated for surface‐bound complement factors and CR1 (CD 35) expression and function. The E were coated with C4b,C3b, and factor H. Following plasma infusion of in vitro incubation of the patients’ E with normal human serum (NHS) or purified factor I, cell‐bound C4b and C3b could no longer be detected. The E now expressed C3d, and factor H was unaffected, indicating that factor H was hound to the C3d part of the C3b molecules, providing the co‐factor for effective cleavage of E‐bound C3b when purified factor 1 was added. The binding of monoclonal anti‐CR1 antibodies (M710) to the patients’ E was markedly reduced compared with control E, and was not normalized by treatment with NHS, probably because covalently bound C3d/factor H interfered with the binding of M710. By contrast, the reduced ability of the patients’ E‐CR1 to bind complement‐opsonized immune complexes (IC) was normalized after plasma infusion. This shows that the impaired CR1 function was acquired and emphasizes the importance of performing functional CR1 assays. Complement opsonization of IC for binding to normal E was severely compromised in the patients’ sera due to consumption of factor B and C3. After plasma infusion the opsonization capacity of the patients’ sera was restored. Thus, two mechanisms of importance for normal clearance of IC were compromised in factor I‐deficient patients: (1) the opsonization of IC for binding to E‐CRI, and (2) the capacity of E‐CRI to bind opsonized complexes. Both dysfunctions were temporarily corrected by plasma infusion.