We investigated the relationship between the respiratory burst in neutrophils and the membrane distribution of the IgG receptor, Fc gamma RIII. Fc gamma RIII receptors were labeled with a fluoresceinated antibody that does not block binding of immune complexes. The respiratory burst was detected using covalently bound rosamine stain previously described for flow cytometric applications. This method allows visualization of intracellular oxidant production in fixed cells using attenuated illumination with a laser. Strong cytosolic oxidation of rosamine was observed only in those cells that displayed prominent receptor endocytosis upon interaction with insoluble immune complexes. Soluble immune complexes or insoluble complexes in the presence of cytochalasin B did not stimulate endocytosis of Fc gamma RIII and induced no rosamine oxidation. Extracellular superoxide production measured by the cytochrome c test did not correlate with intracellular rosamine oxidation: it was maximal in cytochalasin-treated cells and did not require any visible receptor rearrangement. Our results demonstrate the utility of the rosamine stain as an intracellular marker of the oxidative burst, support the role of Fc gamma RIII in neutrophil activation and emphasize the compartmental regulation of the oxidative burst.
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http://dx.doi.org/10.1016/s0171-2985(98)80062-4 | DOI Listing |
Immunogenetics
August 2023
Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center (UTHSC), 910 Madison Avenue, 10th floor Suite 1002, Memphis, TN, 38163, USA.
Though binding sites for the complement factor C1q and the canonical fragment crystallizable (Fc) gamma receptors (Fc[Formula: see text]Rs) on immunoglobulin G (IgG) molecules overlap, how C1q decoration of immune complexes (ICs) influences their ability to engage Fc[Formula: see text]Rs remains unknown. In this report, we use recombinant human Fc multimers as stable IC mimics to show that C1q engagement of ICs directly and transiently inhibits their interactions with Fc[Formula: see text]RIII (CD16) on human natural killer (NK) cells. This inhibition occurs by C1q engagement alone as well as in concert with other serum factors.
View Article and Find Full Text PDFMol Nutr Food Res
May 2023
School of Food Science, Guangdong Pharmaceutical University, Zhongshan, 528453, China.
Scope: Gamma-aminobutyric acid (GABA) represents positive effects in stress model, but the exact antioxidant remains unclear. This study aims to determine what GABA do and how GABA interfere on oxidative stress in the small intestine of radiation-induced intestinal injury (RIII) mice.
Methods And Results: C57BL/6J mice are gavaged.
Rheumatology (Oxford)
September 2023
Department of Rheumatology, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
Objective: Divergent therapeutic outcomes on different disease domains have been noted with IL-23 and IL-17A-blockade in PsA. Therefore, elucidating the role of RORγt, the master regulator of type 17 immune responses, is of potential therapeutic interest. To this end, RORγt inhibition was assessed in combined skin, joint and gut inflammation in vivo, using a PsA model.
View Article and Find Full Text PDFImmunology
November 2022
Laboratório de Interação Microrganismo-Hospedeiro, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Intestinal ischemia and reperfusion (I/R) is accompanied by an exacerbated inflammatory response characterized by deposition of IgG, release of inflammatory mediators, and intense neutrophil influx in the small intestine, resulting in severe tissue injury and death. We hypothesized that Fc RIIb activation by deposited IgG could inhibit tissue damage during I/R. Our results showed that I/R induction led to the deposition of IgG in intestinal tissue during the reperfusion phase.
View Article and Find Full Text PDFBrain Topogr
September 2021
Department of Anatomy, Université du Québec À Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC, G9A 5H7, Canada.
Some pain-related information is processed preferentially in the right cerebral hemisphere. Considering that functional lateralization can be affected by handedness, spinal and cerebral pain-related responses may be different between right- and left-handed individuals. Therefore, this study aimed to investigate the cortical and spinal mechanisms of nociceptive integration when nociceptive stimuli are applied to right -handed vs.
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