The chicken leukocyte receptor complex encodes a primordial, activating, high-affinity IgY Fc receptor.
Fc receptors are key players of the immune system that link the fine specificity of immunoglobulins and innate effector responses. Here, we describe a nonmammalian Fcgamma receptor, CHIR-AB1, a member of the leukocyte receptor complex, that binds IgY with high affinity with its single Ig domain. It is expressed on immature and mature B lymphocytes, monocytes, macrophages, and natural killer cells and harbors motifs of activating and inhibitory Fc receptors. In the absence of FcepsilonRIgamma, CHIR-AB1 can be expressed on B cells but cross-linking does not induce intracellular calcium release. In contrast, cells expressing CHIR-AB1 and FcepsilonRIgamma are triggered to release intracellular calcium upon stimulation with heat-aggregated IgY. CHIR-AB1 thus represents a primordial Fc receptor that combines features of different mammalian counterparts.
Viertlboeck
Birgit C
BC
Institute for Animal Physiology, University of Munich, 80539 Munich, Germany.
Schweinsberg
Sonja
S
Hanczaruk
Matthias A
MA
Schmitt
Ramona
R
Du Pasquier
Louis
L
Herberg
Friedrich W
FW
Göbel
Thomas W
TW
D000818:Animals; D000915:Antibody Affinity / Q000276:immunology; D002460:Cell Line; D002645:Chickens / Q000276:immunology*; D007136:Immunoglobulins / Q000378:metabolism*; D007962:Leukocytes / Q000276:immunology* / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000276:immunology; D011961:Receptors, Fc / Q000235:genetics* / Q000378:metabolism*
C016512:IgY; D007136:Immunoglobulins; D011961:Receptors, Fc