2022年4月12日 · Recognition of iC3b by complement receptor type 3 (CR3) fosters pathogen opsonophagocytosis by macrophages and the stimulation of adaptive immunity by complement-opsonized antigens. Here, we...

Recognition of iC3b by complement receptor type 3 (CR3) fosters pathogen opsonophagocytosis by macrophages and the stimulation of adaptive immunity by complement-opsonized antigens. Here, we present the crystallographic structure of the complex between human iC3b and the von Willebrand A inserted domain of the α chain of CR3 (αI).

2021年6月15日 · Upon interaction with CR3, iC3b rearranges to form a compact receptor–ligand complex. Overall, the data suggest that the iC3b–CR3 interaction is of high affinity and relies on minor contacts formed between CR3 and regions outside the iC3b thioester domain.

2022年4月12日 · Recognition of iC3b by complement receptor type 3 (CR3) fosters pathogen opsonophagocytosis by macrophages and the stimulation of adaptive immunity by complement-opsonized antigens. Here, we present the crystallographic structure of the complex between human iC3b and the von Willebrand A inserted domain of the α chain of CR3 (αI).

A peptide derived from the Ig-like D1 domain competes with ICAM-2 binding to CR3 using a binding site distinct from iC3b, FX, and fibrinogen. Binding of the peptide activates CR3 and increases ICAM-1-mediated neutrophil adhesion as well as CR3´s binding to fibrinogen and iC3b .

CR3 is a β 2-integrin that mediates binding of neutrophils to endothelial cells and is critical for neutrophil recruitment to sites of infection. CR3 mediates phagocytosis of iC3b-coated microbes, enables extravasation of leukocytes from the circulation to sites of injury or infection and facilitates homing of lymphocytes to tissues. The ...

2023年3月6日 · Recognition of iC3b by complement receptor type 3 (CR3) fosters pathogen opsonophagocytosis by macrophages and the stimulation of adaptive immunity by complement-opsonized antigens. Here, we...

2011年7月25日 · Concurrently, surface-bound C3b is proteolyzed to iC3b by factor I and appropriate cofactors. iC3b then interacts with the complement receptors (CR) of the Ig superfamily, CR2 (CD21), CR3 (CD11b/CD18), and CR4 (CD11c/CD18) on leukocytes, down-modulating inflammation, enhancing B cell-mediated immunity, and …

Recognition of iC3b by complement receptor type 3 (CR3) fosters pathogen opsonophagocytosis by macrophages and the stimulation of adaptive immunity by complement-opsonized antigens. Here, we present the crystallographic structure of the complex between human iC3b and the von Willebrand A inserted domain of the α chain of CR3 (αI).

A modular iC3b would facilitate binding by increasing the number of low-affinity contacts (avidity effect), restricting the angular spread of CR3:C3d complexes to increase CR3:iC3b packing efficiency (alignment effect), and making it possible for C3d(g) and C3c moieties from the same or different iC3b molecules to collaborate in CR3 binding.