TY - JOUR
T1 - A complement receptor for opsonized immune complexes on erythrocytes from Oncorhynchus mykiss but not Ictalarus punctatus
AU - Schraml, Barbara
AU - Baker, M. Angeles
AU - Reilly, Brian D.
N1 - Funding Information:
This research was supported in part by a grant from the National Institutes of Health AI050846, and the Howard Hughes Medical Institute Undergraduate Science Education Program at Texas Tech University.
PY - 2006/4
Y1 - 2006/4
N2 - Immune complexes activate the classical pathway of complement resulting in the covalent deposition of fragments of the third (C3b) and fourth (C4b) components of complement, thus opsonizing the complexes for uptake by CD35 found on human erythrocytes. The complexes are then transported to and cleared from the circulation by the reticuloendothelial system. It has been shown that rainbow trout can remove immune complexes from the circulation in a complement-dependent manner similar to that found in the human. However, the cell or cell types involved have not been identified. The purpose of this study was to investigate whether a complement-dependent immune adherence receptor is expressed on erythrocytes from the rainbow trout (Oncorhynchus mykiss) and the channel catfish (Ictalarus punctatus). Coating fluorescent microparticles with BSA, and then binding them to anti-BSA created an artificial immune complex that was incubated with normal fish serum, normal human serum or EDTA-treated serum. The complement-coated immune complexes were then incubated with either fish or human erythrocytes and analyzed for binding by flow cytometry and further visualized by fluorescence microscopy. Our results indicate that erythrocytes from rainbow trout are capable of binding immune complexes when pretreated with serum from either the trout or human, but not when pretreated with serum containing EDTA. By contrast, erythrocytes from the channel catfish did not bind immune complexes pretreated with autologous or human serum. These data suggest that differences exist in receptor distribution between two closely related species of fish, and a potentially homologous relationship in receptor expression, and possibility function, exist between two highly divergent species.
AB - Immune complexes activate the classical pathway of complement resulting in the covalent deposition of fragments of the third (C3b) and fourth (C4b) components of complement, thus opsonizing the complexes for uptake by CD35 found on human erythrocytes. The complexes are then transported to and cleared from the circulation by the reticuloendothelial system. It has been shown that rainbow trout can remove immune complexes from the circulation in a complement-dependent manner similar to that found in the human. However, the cell or cell types involved have not been identified. The purpose of this study was to investigate whether a complement-dependent immune adherence receptor is expressed on erythrocytes from the rainbow trout (Oncorhynchus mykiss) and the channel catfish (Ictalarus punctatus). Coating fluorescent microparticles with BSA, and then binding them to anti-BSA created an artificial immune complex that was incubated with normal fish serum, normal human serum or EDTA-treated serum. The complement-coated immune complexes were then incubated with either fish or human erythrocytes and analyzed for binding by flow cytometry and further visualized by fluorescence microscopy. Our results indicate that erythrocytes from rainbow trout are capable of binding immune complexes when pretreated with serum from either the trout or human, but not when pretreated with serum containing EDTA. By contrast, erythrocytes from the channel catfish did not bind immune complexes pretreated with autologous or human serum. These data suggest that differences exist in receptor distribution between two closely related species of fish, and a potentially homologous relationship in receptor expression, and possibility function, exist between two highly divergent species.
KW - CD35
KW - Catfish
KW - Complement
KW - Trout
UR - http://www.scopus.com/inward/record.url?scp=33644547321&partnerID=8YFLogxK
U2 - 10.1016/j.molimm.2005.09.014
DO - 10.1016/j.molimm.2005.09.014
M3 - Article
C2 - 16271392
AN - SCOPUS:33644547321
SN - 0161-5890
VL - 43
SP - 1595
EP - 1603
JO - Molecular Immunology
JF - Molecular Immunology
IS - 10
ER -