Product Description

CD16a (FcγRIIIa, 176V) is a low-affinity IgG Fc receptor mainly expressed by natural killer (NK) cells, macrophages, and monocytes, playing central roles in antibody-dependent cell-mediated cytotoxicity (ADCC) and immune regulation. CD16a functions by binding to the Fc region of IgG antibodies, activating downstream signaling pathways (e.g., ITAM-dependent Syk and PI3K signaling) that mediate effector cell activation, degranulation, and cytokine release. CD16a exhibits a polymorphism at position 176 (valine V vs phenylalanine F), with the 176V variant displaying higher binding affinity for IgG Fc, thereby enhancing ADCC efficacy and conferring superior therapeutic outcomes in antibody-based treatments. Classic functions of CD16a include NK cells recognizing antibody-coated target cells through CD16a and releasing perforin and granzymes to kill tumor cells or virus-infected cells. Dysregulation of CD16a is associated with various diseases: reduced CD16a expression is linked to immunodeficiencies and chronic infections, whereas overactivation contributes to autoimmune disorders (e.g., rheumatoid arthritis). Consequently, the CD16a 176V high-affinity variant has been widely applied in the design of engineered antibodies (e.g., Fc-optimized monoclonal antibodies) and CAR-NK cell therapy to enhance antibody-dependent antitumor immunity, underscoring the critical role of CD16a in both immune surveillance and biotherapeutics.

Screeningbio’s TR-FRET Human CD16a (FcγRⅢA, 176V) Binding Assay Kit can be used to screen for IgGs that bind to Human CD16a (FcγRⅢA, 176V), and is suitable for functional evaluation of ADCC and ADCP activities of antibody drug candidates. CD16a (FcγRⅢA, 176V) is hereinafter referred to as CD16a (176V). This kit is a competitive immunoassay developed using KeyTec® TR-FRET technology, characterized by simplicity, rapidity, high accuracy, and good reproducibility.

The basic principle of this method is as follows: an anti‑Tag1 antibody conjugated to TR‑FRET Solar Eu*1 specifically recognizes the CD16a (176V) protein bearing Tag1. Human IgG conjugated to TR‑FRET LA*2 binds to the CD16a (176V) protein, bringing the Solar Eu donor and LA acceptor into close proximity. Upon excitation by an external light source, fluorescence resonance energy transfer occurs between the donor and acceptor. The binding level between CD16a (176V) and Human IgG can be determined by measuring the signal intensity at a specific wavelength (665 nm). Free Human IgG or proteins with a human Fc tag in the sample compete with Human IgG‑LA for the binding sites on CD16a (176V), and the TR‑FRET signal intensity is inversely proportional to the concentration of free Human IgG or proteins with a human Fc tag in the sample.