Definition of immunoglobulin A receptors on eosinophils and their enhanced expression in allergic individuals.
Fc alpha receptors (Fc alpha R), detected by the binding of IgA and by anti-Fc alpha R antibodies, were found to be differentially expressed on eosinophils and neutrophils. Neutrophils were the major granulocyte population expressing Fc alpha R, and they expressed much higher levels of Fc alpha R than eosinophils. The expression of Fc alpha R by eosinophils could be upregulated approximately threefold by Ca2+ ionophore treatment in a dose- and time-dependent manner. This effect, which was blocked by a chelating agent, was not duplicated by other cellular stimuli. Eosinophils in allergic individuals displayed enhanced Fc alpha R expression, whereas neutrophils did not. The Fc alpha R on eosinophils had a higher molecular mass (70-100 kD) than those identified on neutrophils (55-75 kD). However, removal of N-linked carbohydrates from Fc alpha R of eosinophils and neutrophils revealed a major protein core of 32 kD for both cell types. The data indicate that expression of Fc alpha R molecules with a characteristic glycosylation pattern is upregulated on eosinophils in allergic individuals.
Monteiro
R C
RC
Department of Pediatrics, University of Alabama at Birmingham.
Hostoffer
R W
RW
Cooper
M D
MD
Bonner
J R
JR
Gartland
G L
GL
Kubagawa
H
H
D000328:Adult; D000911:Antibodies, Monoclonal; D001249:Asthma / Q000097:blood / Q000276:immunology*; D002118:Calcium / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004804:Eosinophils / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D011961:Receptors, Fc / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D012016:Reference Values; D012220:Rhinitis / Q000097:blood / Q000276:immunology*; D015854:Up-Regulation / Q000187:drug effects
D000911:Antibodies, Monoclonal; C045281:IgA receptor; D007070:Immunoglobulin A; D011961:Receptors, Fc; D004533:Egtazic Acid; D002118:Calcium