Previous studies from our laboratories have demonstrated that granulocytes (PMNs), when exposed to activated complement (C) (specifically C5a), will aggregate and be provoked to damage cultured endothelial cells in vitro; it was postulated that these phenomena might also occur in vivo, constituting a previously unsuspected mechanism of immune tissue damage. The studies here presented confirm by intravital microscopy that PMN aggregation and leukoembolization in fact occur in live animals when C is activated or C5a is infused, and that these are accompanied by extravasation of plasma proteins in a pattern suggesting endothelial damage. It is concluded that altered microvascular behavior of PMNs is a possible pathogenetic mechanism in disease states associated with C activation.
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Cell
February 2024
Department of Immunology, Harvard Medical School, Boston, MA 02115, USA. Electronic address:
Canonically, the complement system is known for its rapid response to remove microbes in the bloodstream. However, relatively little is known about a functioning complement system on intestinal mucosal surfaces. Herein, we report the local synthesis of complement component 3 (C3) in the gut, primarily by stromal cells.
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March 2021
Research Center of Allergy & Immunology, Shenzhen University School of Medicine, Shenzhen, China.
The pathogenesis of ulcerative colitis (UC) is to be further investigated. House dust mites (HDM) are highly associated with the pathogenesis of immune inflammation in the body. This study aims to investigate the role of enolase (one of the HDM-derived proteins)-specific cross Abs in the induction of UC-like inflammation.
View Article and Find Full Text PDFInfect Immun
June 2020
Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
The human respiratory tract pathogen , which causes mild to severe infections, has been associated with the development of chronic inflammatory diseases. To understand the biology of infections, several studies have investigated the interaction between and professional phagocytes. However, these studies have been conducted under nonopsonizing conditions, making the role of opsonization in infections elusive.
View Article and Find Full Text PDFJ Surg Res
October 2011
Department of Physiology and Biophysics, University of Louisville, Louisville, Kentucky, USA.
Background: Excessive complement activation is an integral part of ischemia and reperfusion (IR) injury (IRI) of organs. In kidney transplantation, the pathologic consequence of IRI and complement activation can lead to delayed graft function, which in turn is associated with acute rejection. Previous strategies to reduce complement-induced IRI required systemic administration of agents, which can lead to increased susceptibility to infections/immune diseases.
View Article and Find Full Text PDFBlood
January 2011
INSERM U845, Université René Descartes, Hôpital Necker, 161 rue de Sèvres, Paris, France.
Complement alternative pathway plays an important, but not clearly understood, role in neutrophil-mediated diseases. We here show that neutrophils themselves activate complement when stimulated by cytokines or coagulation-derived factors. In whole blood, tumor necrosis factor/formyl-methionyl-leucyl-phenylalanine or phorbol myristate acetate resulted in C3 fragments binding on neutrophils and monocytes, but not on T cells.
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