Interaction of non-adherent suspended neutrophils to complement opsonized pathogens: a new assay using optical traps  

作　　者：TomokoSUZUki MasaruYanai HiroshiKubo AkiOKanda HidetadaSasaki James P Butler 

机构地区：[1]Department of Geriatric and Respiratory Medicine,Tohoku University School of Medicine,Sendai 980-8574,Japan [2]Physiology Program,Harvard School of Public Health,Boston,MA 02115 [3]USA

出　　处：《Cell Research》2006年第11期887-894,共8页细胞研究（英文版）

摘　　要：Phagocytosis of opsonized pathogens by circulating non-adherent neutrophils is an essential step in host defense, which when overwhelmed contributes to sepsis. To investigate the role played by ligation of complement receptors CR3 and CR4 in non-adherent neutrophils, we designed a novel assay system utilizing dual optical traps, respectively, holding a suspended unactivated cell and presenting a specific ligand-coated bead to the cell surface. We chose anti-CD 18 as an example ligand, mimicking the bacterial opsonizing complement fragment iC3b. Presentation of anti-CD 18-coated beads elicited both pseudopodial protrusion and subsequent phagocytosis. This is in sharp contrast to previously reported responses of adherent neutrophils, which phagocytize opsonized particles without pseudopod formation. We used this same new assay to probe actomyosin pathways in the neutrophil＇s pseudopodial and phagocytic response. Disruption of actin or inhibition of myosin light-chain kinase dose-dependently reduced pseudopod formation and phagocytosis rates. In summary, i） the new dual trap assay can be used to study the responses of suspended neutrophils to a variety of ligands, and ii） in a first application of this technique, we found that local ligation of CR3/4 in unactivated neutrophils in suspension induces pseudopod formation and phagocytosis at that site, and that these events occur via an actomyosindependent pathway.

关 键 词：neutrophil PHAGOCYTOSIS pseudopod formation ACTOMYOSIN COMPLEMENT CR3/4 receptor 

分 类 号：R392[医药卫生—免疫学]