TY - JOUR
T1 - Immune complexes bind preferentially to specific subpopulations of human erythrocytes
AU - Cosio, Fernando G.
AU - Xiao-Ping, Shen
AU - Hebert, Lee A.
N1 - Funding Information:
This work was supported in part by NIH Grant HL 25404, a Research Challenge Grant from The Ohio State University Office of Research and Graduate Studies, and the William H. Davis Scholarship Fund. We thank Alan P. Bakaletz and Dan J. Birmingham for their technical assistance. Special thanks to Harry Luffman from the Ohio State University Comprehensive Cancer Center for his help with the flow cytometry analysis. Thank you to Mrs. Carmela Price for secretarial assistance.
PY - 1990/6
Y1 - 1990/6
N2 - Primate erythrocytes have complement receptors (CR1) that, both in vivo and in vitro, bind immune complexes (IC) opsonized with C3b. The present study was undertaken to determine whether the ability of human erythrocytes to bind IC is a characteristic shared by all erythrocytes. Binding of IC to erythrocytes probably involves the interaction of several C3b molecules with several CR1 clustered in small areas of the erythrocyte surface. To identify IC binding CR1 clusters, we first assessed the binding to erythrocytes of fluorescein-labeled polystyrene beads coated with monoclonal anti-CR1 antibodies (anti-CR1-beads) and second, preformed IC. The binding of these ligands to erythrocytes was evaluated by immunofluorescence microscopy and flow cytometry. We found that only a fraction of erythrocytes from normal individuals bound anti-CR1-beads specifically and the percentage of erythrocytes able to bind beads increased with increasing numbers of CR1 per erythrocyte. However, the number of anti-CR1-beads bound per erythrocyte varied among cells from the same individual. We demonstrated further that the erythrocyte binding sites for anti-CR1-beads are also binding sites for opsonized IC. This was shown by demonstrating that anti-CR1-beads inhibited the binding of opsonized IC to erythrocytes and opsonized IC inhibited the binding of anti-CR1-beads to erythrocytes. Incubation of erythrocytes with opsonized IC, followed by FITC-labeled secondary antibodies, confirmed that indeed only a fraction of erythrocytes is capable of binding opsonized IC and that the binding sites for IC occupy small regions on the erythrocyte membrane. By contrast, we demonstrated that greater than 90% of erythrocytes express CR1. In conclusion, only some erythrocytes have the capacity to bind IC. Differences in the ability of erythrocytes to bind IC are probably related to differences in the clustering of CR1 in the erythrocyte membrane. Anti-CR1-beads identify erythrocyte binding sites for IC. These beads should prove useful to assess the changes that occur in the erythrocyte CR1 after exposure to IC in vivo.
AB - Primate erythrocytes have complement receptors (CR1) that, both in vivo and in vitro, bind immune complexes (IC) opsonized with C3b. The present study was undertaken to determine whether the ability of human erythrocytes to bind IC is a characteristic shared by all erythrocytes. Binding of IC to erythrocytes probably involves the interaction of several C3b molecules with several CR1 clustered in small areas of the erythrocyte surface. To identify IC binding CR1 clusters, we first assessed the binding to erythrocytes of fluorescein-labeled polystyrene beads coated with monoclonal anti-CR1 antibodies (anti-CR1-beads) and second, preformed IC. The binding of these ligands to erythrocytes was evaluated by immunofluorescence microscopy and flow cytometry. We found that only a fraction of erythrocytes from normal individuals bound anti-CR1-beads specifically and the percentage of erythrocytes able to bind beads increased with increasing numbers of CR1 per erythrocyte. However, the number of anti-CR1-beads bound per erythrocyte varied among cells from the same individual. We demonstrated further that the erythrocyte binding sites for anti-CR1-beads are also binding sites for opsonized IC. This was shown by demonstrating that anti-CR1-beads inhibited the binding of opsonized IC to erythrocytes and opsonized IC inhibited the binding of anti-CR1-beads to erythrocytes. Incubation of erythrocytes with opsonized IC, followed by FITC-labeled secondary antibodies, confirmed that indeed only a fraction of erythrocytes is capable of binding opsonized IC and that the binding sites for IC occupy small regions on the erythrocyte membrane. By contrast, we demonstrated that greater than 90% of erythrocytes express CR1. In conclusion, only some erythrocytes have the capacity to bind IC. Differences in the ability of erythrocytes to bind IC are probably related to differences in the clustering of CR1 in the erythrocyte membrane. Anti-CR1-beads identify erythrocyte binding sites for IC. These beads should prove useful to assess the changes that occur in the erythrocyte CR1 after exposure to IC in vivo.
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U2 - 10.1016/0090-1229(90)90123-8
DO - 10.1016/0090-1229(90)90123-8
M3 - Article
C2 - 2140304
AN - SCOPUS:0025282213
SN - 0090-1229
VL - 55
SP - 337
EP - 354
JO - Clinical Immunology and Immunopathology
JF - Clinical Immunology and Immunopathology
IS - 3
ER -