Fc Receptors

Fc receptor-like 6 (FCRL6), the most recently characterized member of the FCRL family, is a cell surface glycoprotein with tyrosine-based regulatory potential. An extensive survey of human hematopoietic tissues disclosed that FCRL6 expression by NK- and T-cell subpopulations increases as a function of differentiation and is remarkably restricted to mature lymphocytes with cytotoxic capability.

As a monomeric immunoglobulin that is predominately involved in the secondary antibody response and the only isotype that can pass through the human placenta, Immunoglobulin G (IgG) is synthesized and secreted by plasma B cells. IgG antibodies protect the body against the pathogens by agglutination and immobilization, complement activation, toxin neutralization, as well as the antibody-dependent cell-mediated cytotoxicity (ADCC). IgG tetramer contains two heavy chains (50 kDa ) and two light chains (25 kDa) linked by disulfide bonds, that is the two identical halves form the Y-like shape. IgG is digested by pepsin proteolysis into Fab fragment (antigen-binding fragment) and Fc fragment ( crystallizable fragment). IgG1 is most abundant in serum among the four IgG subclasses (IgG1, 2, 3 and 4) and binds to Fc receptors (FcγR ) on phagocytic cells with high affinity.

FcγRIIB is a low affinity receptor that recognizes the Fc portion of IgG. The human CD32 group consists of FcγRIIA, FcγRIIB, and FcγRIIC proteins that share 94-99% sequence identity in their extracellular domains but differ substantially in their transmembrane and cytoplasmic domains. FcγRII protein is expressed on cells of both myeloid and lymphoid lineages as well as on cells of non-hematopoietic origin. FcγRIIB has an intrinsic cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM) and delivers an inhibitory signal upon ligand binding. Ligation of FcγRIIB on B cells down-regulates antibody production and in some circumstances may promote apoptosis. Co-ligation of FcγRIIB on dendritic cells inhibits maturation and blocks cell activation. FcγRIIB may also be a target for monoclonal antibody therapy for malignancies. FcγRIIB plays an important negative-regulating role through modulating the signals from activation receptors.

FcRH5 is a cell surface marker enriched on malignant plasma cells when compared to other hematologic malignancies and normal tissues. DFRF4539A is an anti-FcRH5 antibody-drug conjugated to monomethyl auristatin E (MMAE), a potent anti-mitotic agent. FcRH5/FcRL5 Protein (Primary Amine Labeling), Human, Recombinant (His), Biotinylated is expressed in HEK293 mammalian cells with C-His tag. The predicted molecular weight is 92.38 kDa and the accession number is AAK93971.

Human Fc gamma RIIIA/CD16a Protein is a receptor for the Fc region of IgG. Binds complexed or aggregated IgG and also monomeric IgG. Mediates antibody-dependent cellular cytotoxicity (ADCC) and other antibody-dependent responses, such as phagocytosis. Fc gamma RIIIA/CD16a (V176) Domain 2 Protein, Human, Recombinant (mFc) is expressed in HEK293 mammalian cells with C-mFc tag. The predicted molecular weight is 35.29 kDa and the accession number is AAH17865.

Low affinity immunoglobulin gamma Fc region receptor III-B, also known as Fc-gamma RIII-beta, FcR-10, IgG Fc receptor III-1, FCG3, FCGR3, CD16b and FCGR3B. FCGR3B is a GPI-anchor membrane protein and contains two Ig-like C2 type domains. FCGR3B can be expressed in orphonuclear leukocytes and stimulated eosinophils. FCGR3B can interact with INPP5D/SHIP1. FCGR3B localizes in the FCGR gene cluster is a CN polymorphic gene involved in the recruitment of polymorphonuclear neutrophils to sites of inflammation and their activation. FCGR3B may serve as a trap for immune complexes in the peripheral circulation which does not activate neutrophils.

Immunoglobulin G (IgG) is a type of antibody composed of four peptide chains—two identical heavy chains and two identical light chains arranged in a Y-shape typical of antibody monomers.There are four IgG subclasses (IgG1, 2, 3, and 4) in humans, named in order of their abundance in serum. The IgG2a isotype was able to interact very efficiently with FcgammaR, and share approximately 64-78% amino acid sequence identity with IgG1 and IgG2b in the heavy chain constant region domains, CH1, CH2 and CH3, which cause the diffrence in the interaction with complement, NK and mast cells, induction or inhibition by specific cytokines, and ability to cross the placenta.

CD16a Protein, Human, Recombinant (176F, His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 23.3 kDa and the accession number is P08637-1.

FCGRT & B2M Heterodimer Protein, Rat, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 44 kDa and the accession number is P13599&P07151.

Fc epsilon RI Protein, Mouse, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 48 kDa and the accession number is P20489.

FCGR4 Protein, Mouse, Recombinant (His & Avi) is expressed in HEK293 mammalian cells with His and Avi tag. The predicted molecular weight is 24.2 kDa and the accession number is A0A0B4J1G0.

IgG2 Protein, Human, Recombinant (S257A) is expressed in HEK293 mammalian cells. The predicted molecular weight is 25 kDa and the accession number is P01859.

IgG4 Protein, Human, Recombinant (S108P) is expressed in HEK293 mammalian cells. The predicted molecular weight is 25.5 kDa and the accession number is P01861.

IgG2a Protein, Mouse, Recombinant is expressed in HEK293 mammalian cells. The predicted molecular weight is 26.4 kDa and the accession number is P01863.

IgG2b Protein, Mouse, Recombinant is expressed in HEK293 mammalian cells. The predicted molecular weight is 26.3 kDa and the accession number is P01867-2.

CD16/FCGR3 Protein, Mouse, Recombinant (aa 32-215, His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 22.6 kDa and the accession number is P08508-1.

CD32A Protein, Human, Recombinant (167 His, His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 22 kDa and the accession number is P12318-1.

IgE Fc Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 37.4 kDa.

CD32A Protein, Rhesus, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 21.7 kDa and the accession number is H9BMP0.

CD16b Protein, Human, Recombinant (NA2,His & Avi) is expressed in HEK293 mammalian cells with His and Avi tag. The predicted molecular weight is 24.1 kDa and the accession number is O75015.2.

FCGRT & B2M Heterodimer Protein, Rat, Recombinant (His), Biotinylated is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 44 kDa and the accession number is P13599&P07151.

CD16b Protein, Human, Recombinant (NA2), Biotinylated is expressed in E. coli expression system. The predicted molecular weight is 20 kDa and the accession number is O75015.2.

Fc epsilon RI Protein, Human, Recombinant is expressed in HEK293 mammalian cells. The predicted molecular weight is 21 kDa and the accession number is P12319.

CD64A Protein, Rabbit, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 32.2 kDa and the accession number is G1SJM8.

FCAMR/CD351 Protein, Mouse, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 46.4 kDa and the accession number is Q2TB54-2.

Mouse Fc receptor-like protein 1 (FCRL1) is a single-pass type I membrane protein. It is expressed in B-cells at the various stages of differentiation. Mouse FCRL1 consists of a 203 amino acid (aa) extracellular domain (ECD) with two Ig‑like domains, a 21 aa transmembrane segment, and a 103 aa cytoplasmic domain with two immunotyrosine activation motifs (ITAMs). FCRL1 is likely not a receptor for immunoglobulin. It may function as an activating coreceptor in B-cells and B-cells differentiation.

Human Fc gamma RIIIB/CD16b Protein is a receptor for the Fc region of immunoglobulins gamma. Low affinity receptor. Binds complexed or aggregated IgG and also monomeric IgG. Contrary to III-A, is not capable to mediate antibody-dependent cytotoxicity and phagocytosis. May serve as a trap for immune complexes in the peripheral circulation which does not activate neutrophils. Fc gamma RIIIB/CD16b (NA2) Protein, Human, Recombinant (His & Avi) is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 23.7 kDa and the accession number is O75015-1.

Immunoglobulin Kappa is constant region of immunoglobulin light chains. Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into immunoglobulins-secreting plasma cells. Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens. The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light chain. Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen. The variable domains are assembled by a process called V-(D)-J rearrangement and can then be subjected to somatic hypermutations which, after exposure to antigen and selection, allow affinity maturation for a particular antigen.

Human Fc gamma RIIIB/CD16b Protein is a receptor for the Fc region of immunoglobulins gamma. Low affinity receptor. Binds complexed or aggregated IgG and also monomeric IgG. Contrary to III-A, is not capable to mediate antibody-dependent cytotoxicity and phagocytosis. May serve as a trap for immune complexes in the peripheral circulation which does not activate neutrophils. Fc gamma RIIIB/CD16b (NA2) Protein, Human, Recombinant (His & Avi), Biotinylated is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 23.7 kDa and the accession number is O75015-1.

Fc gamma RIIA/CD32a (R167) Protein, Human, Recombinant (His & Avi) is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 23.2 kDa and the accession number is P12318-1.

The Fc gamma Rs have been divided into three classes based on close relationships in their extracellular domains; these groups are designated Fc gamma  RI (also known as CD64), Fc gamma  RII (CD32), and Fc gamma  RIII (CD16). Each group may be encoded by multiple genes and exist in different isoforms depending on species and cell type. Fc gamma RI/CD64 Protein, Human, Recombinant (His & Avi) is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 33.5 kDa and the accession number is P12314-1.

Fc gamma RIIA/CD32a (H167) Protein, Human, Recombinant (His & Avi), Biotinylated is expressed in HEK293 mammalian cells with C-His-Avi tag. The predicted molecular weight is 23.2 kDa and the accession number is P12318-1.

Immunoglobulin G (IgG) Fc receptors play a critical role in linking IgG antibody-mediated immune responses with cellular effector functions. A high resolution map of the binding site on human IgG1 for human Fc gamma RI, Fc gamma RIIA, Fc gamma RIIB, Fc gamma RIIIA, and FcRn receptors has been determined.A common set of IgG1 residues is involved in binding to all Fc gamma R; Fc gamma RII and Fc gamma RIII also utilize residues outside this common set.

FcRH5 is a cell surface marker enriched on malignant plasma cells when compared to other hematologic malignancies and normal tissues. DFRF4539A is an anti-FcRH5 antibody-drug conjugated to monomethyl auristatin E (MMAE), a potent anti-mitotic agent. FcRH5/FcRL5 Protein, Human, Recombinant (His & Avi), Biotinylated is expressed in HEK293 mammalian cells with N-His-Avi tag. The predicted molecular weight is 94.19 kDa and the accession number is Q96RD9-1.

Low affinity immunoglobulin gamma Fc region receptor II (CD32B) is a single-pass type I membrane protein and contains 2 Ig-like C2-type (immunoglobulin-like) domains. The inhibitory CD32B is expressed on B cells and myeloid dendritic cells. Ligation of CD32B on B cells downregulates antibody production and may, in some circumstances, promote apoptosis. Co-ligation of CD32B on dendritic cells inhibits maturation and blocks cell activation. CD32B may also be a target formonoclonal antibody therapy for malignancies.

CD32B/Fcgr2b Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 20.8 kDa and the accession number is P31994-2.

FCGRT & B2M Heterodimer Protein, Cynomolgus, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 43.5 kDa and the accession number is Q8SPV9&Q8SPW0.

CD32B/Fcgr2b Protein, Cynomolgus, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 20.9 kDa and the accession number is Q8SPW3.

CD16/FCGR3 Protein, Rhesus, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 22.7 kDa and the accession number is A0A140HDP8.

IgG Protein, Rabbit, Recombinant (T185A, N284S) is expressed in HEK293 mammalian cells. The predicted molecular weight is 25 kDa and the accession number is P01870.

CD64 Protein, Mouse, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 32 kDa and the accession number is P26151.

CD32A Protein, Human, Recombinant (167 Arg, His & Avi), Biotinylated is expressed in HEK293 mammalian cells with His and Avi tag. The predicted molecular weight is 23.7 kDa and the accession number is P12318-1.

CD16a Protein, Human, Recombinant (176 Phe, His) is expressed in CHO mammalian cells with His tag. The predicted molecular weight is 23.3 kDa and the accession number is P08637-1.

CD32B/Fcgr2b Protein, Human, Recombinant (His & Avi), Biotinylated is expressed in HEK293 mammalian cells with His and Avi tag. The predicted molecular weight is 24 kDa and the accession number is P31994-2.

Fc epsilon RI Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 22.5 kDa and the accession number is P12319.

The Fc receptor with low affinity for IgG (FCGR3, or CD16) is encoded by 2 nearly identical genes, FCGR3A and FCGR3B, resulting in tissue-specific expression of alternative membrane-anchored isoforms. FCGR3A, it is also known as CD16a, encodes a transmembrane protein expressed on activated monocytes/macrophages, natural killer (NK) cells, and a subset of T cells. CD16a / FCGR3A is a receptor expressed on NK cells that facilitates antibody dependent cellular cytotoxicity (ADCC) by binding to the Fc portion of various antibodies. CD16a / FCGR3A also has a broader function. CD16a / FCGR3A is directly involved in the lysis of some virus-infected cells and tumor cells by NK cells, independent of antibody binding. Cross-linking of CD16a / FCGR3A on NK cells resulted in increased intracellular Ca2+ levels and a cascade of biochemical events similar to those activated by the T cell receptor. CD16a / FCGR3A on human NK cells is a lysis receptor that mediates the direct killing of some virus infected and tumor cells, independent of antibody ligation.

IgG3 Protein, Human, Recombinant is expressed in HEK293 mammalian cells. The predicted molecular weight is 31.2 kDa and the accession number is P01860.

CD89 Protein, Rat, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 24.8 kDa and the accession number is NP_973721.1.

CD23 Protein, Rat, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 77.7 kDa and the accession number is Q6AZ45.

CD16a Protein, Cynomolgus, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 23.1 kDa and the accession number is Q8SPW2.1.