Human neutrophils constitutively synthesize two receptors for the constant region of IgG, FcgammaRII, and FcgammaRIIIB. Fluo-3-loaded neutrophils were treated with biotinylated Fab fragments of anti-FcgammaR antibodies and cross-linked with streptavidin, and intracellular calcium ([Ca2+](i)) was monitored by flow cytometry. Polymerization of filamentous actin was quantitated by NBD-phallacidin using flow cytometry. Cross-linking of FcgammaRII by monoclonal antibody (mAb) IV.3 induces an increase in [Ca2+](i), superoxide generation, and the polymerization of actin. [Ca2+](i) responses from cross-linking of FcgammaRIIIB by mAb 3G8 varied from minimal to no release. To determine whether discrepancies in 3G8-induced [Ca2+](i) release were due to allotype variation, we selected five donors who were homozygous for the NA1 allotype of FcgammaRIIIB and five who were either heterozygous or homozygous for the NA2 allotype and compared their [Ca2+](i) response and actin polymerization induced by FcgammaRIIIB cross-linking. Cross-linking of FcgammaRIIIB by 3G8 produced minimal [Ca2+](i) release and polymerization of actin irrespective of donor allotype.
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Exp Cell Res
January 2018
Kidney Disease Center, First Affiliated Hospital, Zhejiang University, School of Medicine, Key Laboratory of Nephropathy, Zhejiang Province, Hangzhou, Zhejiang, China; National Clinical Research Base of Traditional Chinese Medicine, Zhejiang Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, Hangzhou, China. Electronic address:
Two different types of FcRs for IgG are constitutively expressed on the surface of human neutrophils, namely, FcγRIIA (CD32a) and FcγRIIIB (CD16b). Unlike FcγRIIA, FcγRIIIb is GPI anchored to the cell membrane and its signal transduction is still ambiguous. To further understand the signal transduction of CD16b, we compared neutrophil cytokine expression and apoptosis by the cross-linking of CD32a and CD16b respectively.
View Article and Find Full Text PDFFront Immunol
August 2016
Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Ciudad de México , Mexico.
Neutrophils (PMNs) are the most abundant leukocytes in the blood. PMN migrates from the circulation to sites of infection where they are responsible for antimicrobial functions. PMN uses phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to kill microbes.
View Article and Find Full Text PDFJ Immunol Res
November 2016
Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, 04510 México, DF, Mexico.
Neutrophils (PMN) are the most abundant leukocytes in the blood. PMN migrate from the circulation to sites of infection, where they are responsible for antimicrobial functions. PMN use phagocytosis, degranulation, and formation of neutrophil extracellular traps (NETs) to kill microbes.
View Article and Find Full Text PDFJ Infect Dis
January 2014
Department of Clinical Biochemistry and Immunology, Statens Serum Institut.
Immunoglobulin G (IgG) cross-linking with Fc gamma receptor IIIB (FcγRIIIB) triggers neutrophil degranulation, releasing reactive oxygen species with high levels associated with protection against malaria. The FCGR3B-c.233C>A polymorphism thought to influence the interaction between IgG and FcγRIIIB was recently associated with malaria.
View Article and Find Full Text PDFLeuk Res
May 2010
Antibody Research Laboratories, Research Division, Kyowa Hakko Kirin Co, Ltd, 3-6-6, Asahi-machi, Machida-shi, Tokyo 194-8533, Japan.
We demonstrate herein the augmentation of rituximab-mediated apoptosis in lymphoma cell lines by cross-linking with recombinant FcgammaRs, which is further enhanced by using a nonfucosylated variant of rituximab having strong FcgammaRIII-binding capacity. Furthermore, we show that neutrophils can serve as physiological cross-linkers that augment anti-CD20-mediated apoptosis, as evidenced by (i) the neutrophil-augmented apoptosis was more profound for the nonfucosylated variant of rituximab and (ii) the mechanism depended on FcgammaRIIIb but not on FcgammaRIIa. Taken together, we suggest a potential anti-tumour mechanism of nonfucosylated anti-CD20 antibody by which antibody molecules are cross-linked through enhanced interaction with FcgammaRIIIb in neutrophils.
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