What is FcgRIIa?
What is FcgRIIa?
FcgRIIa is a unique and the most widespread activating FcR in humans that through avid binding of immune complexes potently triggers inflammation. Polymorphisms of FcgRIIa (high responder/low responder [HR/LR]) are linked to susceptibility to infections, autoimmune diseases, and the efficacy of therapeutic Abs.
What is Fcγriia?
the low-affinity receptor FcεRII (CD23) is a C-type lectin. FcεRII has multiple functions as a membrane-bound or soluble receptor; it controls B cell growth and differentiation and blocks IgE-binding of eosinophils, monocytes, and basophils.
Do t cells express Fc receptors?
The different cell types of the lymphoid-myeloid lineage constitutively express various Fc receptors. The exception is the T-cell lineage where most subsets express Fc receptors only during a narrow window following cellular activation.
Do CD8 T cells express Fc receptors?
A macrophage cell line was used as a positive control for the expression of FcγR1 and FcγRIIB (Fig. 2a⇓). Activated self-specific CD8 T cells express a low affinity FcR similar to NK cells.
What is the fcgamma receptor?
Fc-gamma receptors (FcγRs) recognize IgG-coated targets, such as opsonized pathogens or immune complexes (ICs). Cross-linking leads to internalization of the cargo with associated activation of down-stream signaling cascades.
What is Fab immunology?
The fragment antigen-binding (Fab fragment) is a region on an antibody that binds to antigens. It is composed of one constant and one variable domain of each of the heavy and the light chain.
What is Fcyriia?
The low affinity receptor for IgG, FcyRII, is. expressed on most hematopoietic cells, and through the. binding of immune complexes mediates a large spec- trum of biological responses vital for resistance to infec- tion and the regulation of immunity.
What is the function of the Fc region?
By binding to specific proteins the Fc region ensures that each antibody generates an appropriate immune response for a given antigen. The Fc region also binds to various cell receptors, such as Fc receptors, and other immune molecules, such as complement proteins.
What triggers a secondary immunological response?
In brief, when B and T-cells replicate during the primary immune response, they produce effector cells and long-lived memory cells. Memory B and T-cells are antigen-specific and, on encountering the antigen again, can mount a more rapid and effective immune response, known as the secondary immune response.
What is Fc in immunology?
The fragment crystallizable region (Fc region) is the tail region of an antibody that interacts with cell surface receptors called Fc receptors and some proteins of the complement system. This property allows antibodies to activate the immune system.
What is FcR gamma?
The Fc receptor (FcR) gamma subunit is essential for IgE-binding activity of cell-surface expressed chimeric receptor molecules constructed from human high-affinity IgE receptor (Fc epsilon RI) alpha and FcR gamma subunits. Mol Immunol.
What is the difference between FcγRIIA and fcβriib?
The FcγRIIA (also FcγRIIC) and FcγRIIB proteins have opposing cellular functions. FcγRIIA proteins are activating-type Fc receptors. In contrast, FcγRIIB is a key immune checkpoint that modulates the action of activating-type Fc receptors and the antigen receptor of B cells.
What is the function of FcγRIIB in B cells?
In B cells co-crosslinking of the BCR and FcγRIIb results in the inhibition of activation, proliferation, Ag internalization and Ab secretion ( 30 – 32 ). Moreover, in vitro studies have shown that FcγRIIb on B cells can induce apoptosis upon clustering ( 10, 12, 28, 33, 34 ). FcγRIIb can also function as an endocytic receptor of small ICs.
What does FcγRII stand for?
The human FcγRII family (also known as CD32 in the Cluster of Differentiation nomenclature) consists of a family of primarily cell membrane receptor proteins. They are encoded by the mRNA splice variants of three highly related genes— FCGR2A, FCGR2B, and FCGR2C, which arose by recombination of the FCGR2A and FCGR2B genes ( 3 ).
What is FcγRIIB in the efferent phase?
In the efferent phase, FcγRIIb sets a threshold for the activation by IgG-IC of myeloid effector cells, e.g., monocytes, Mφs, and neutrophils.
