What is CR3 immunology?

What is CR3 immunology?

Macrophage-1 antigen (hereafter complement receptor 3 or CR3) (CD11b/CD18) is a human cell surface receptor found on B and T lymphocytes, polymorphonuclear leukocytes (mostly neutrophils), NK cells, and mononuclear phagocytes like macrophages. CR3 also recognizes iC3b when bound to the surface of foreign cells.

What is pfizer CR3 and CR4?

CR3 and CR4 belong to the family of β2-integrins and play an important role in phagocytosis, cellular adherence and migration. CR3 and CR4 are generally expected to mediate similar functions due to their structural homology, overlapping ligand specificity and parallel expression on human phagocytes.

What is the role of iC3b?

iC3b is a protein fragment that is part of the complement system, a component of the vertebrate immune system. iC3b is produced when complement factor I cleaves C3b. Complement receptors on white blood cells are able to bind iC3b, so iC3b functions as an opsonin.

Which receptor recognize iC3b?

Complement receptors After opsonization, iC3b and C3b are recognized by different receptors: CR3 (CD11b/CD18) found on almost all phagocytes; and CR4 (CD11c/CD18) or gp150,95 found on some lymphocytes and phagocytes.

What is immune complex formation?

An immune complex is formed from the integral binding of an antibody to a soluble antigen. The bound antigen acting as a specific epitope, bound to an antibody is referred to as a singular immune complex.

What does VLA 4 do?

The integrin VLA-4 is expressed on the cell surfaces of stem cells, progenitor cells, T and B cells, monocytes, natural killer cells, eosinophils, and neutrophils. It functions to promote an inflammatory response by the immune system by assisting in the movement of leukocytes to tissue that requires inflammation.

Is iC3b an Opsonin?

Although both C3b and iC3b function as opsonins, they act through different complement receptors, complement receptor 1 (CD35) and complement receptor 3 (CD11b/CD18), respectively (reviewed in reference 1).

What causes immune complex disease?

Immune complex diseases are a group of conditions resulting from inflammation and tissue damage induced in tissues where immune complexes are formed or deposited.

Which of the following are involved in immune complex diseases?

These diseases include rheumatoid arthritis, where an inflammatory response is induced by antibody–antigen complexes in the synovial fluid; types of glomerulonephritis, due to complex trapping within the glomerulus, or retention of antibody-antigen in the glomerulus; extrinsic allergic alveolitis, as in “farmer’s lung” …

Is VCAM an integrin?

VCAM-1 is a ligand for the α4β1 integrin (VLA-4) and binds weakly to α4β7 (102,205–207). A single VCAM-1 gene gives rise through alternative splicing to distinct isoforms (204, 208–211). The major form of VCAM-1 in humans contains seven Ig domains of which domains 1–3 are homologous to domains 4–6 (204).

Is VLA-4 an integrin?

VLA-4 is also a member of the integrin family (α4β1). VLA-4 can bind to vascular cellular adhesion molecule 1 (VCAM-1). VLA-4 ligation has been shown to augment TCR-mediated T cell proliferation, presumably in a similar manner to ligation of LFA-1, by increasing the strength of the signal delivered by the TCR.

What are complement receptors CR3 and CR4?

Complement receptors (CR) 3 and 4 belong to the family of beta-2 (CD18) integrins. CR3 and CR4 are often co-expressed in the myeloid subsets of leukocytes, but they are also found in NK cells and activated T and B lymphocytes.

What is the function of CD11b Cr3?

Complement receptor 3 (CR3)(CD11b/CD18) is a human cell surface receptor found on polymorphonuclear leukocytes (mostly neutrophils), NK cells, and mononuclear phagocytes like macrophages. CR3 is a pattern recognition receptor, capable of recognizing and binding to many molecules found on the surfaces of invading bacteria.

What does Cr3 stand for?

Complement receptor 3 (CR3)(CD11b/CD18) is a human cell surface receptor found on polymorphonuclear leukocytes (mostly neutrophils), NK cells, and mononuclear phagocytes like macrophages.

What is the mechanism of action of c3cr3?

CR3 binds the C3d fragment of C3 in a way permitting CR2 also to bind concomitantly. This enables a hand-over of complement-opsonized antigens from the cell surface of CR3-expressing macrophages to the CR2-expressing B lymphocytes, in consequence acting as an antigen presentation mechanism.