Fc gamma RIIIA/CD16a Overexpression Lysate

HEK293T cells in 10-cm dishes were transiently transfected with a non-lipid polymer transfection reagent specially designed and manufactured for large volume DNA transfection. Transfected cells were cultured for 48hrs before collection. The cells were lysed in modified RIPA buffer (25mM Tris-HCl pH7.6, 150mM NaCl, 1% NP-40, 1mM EDTA, 1xProteinase inhibitor cocktail mix, 1mM PMSF and 1mM Na3VO4, and then centrifuged to clarify the lysate. Protein concentration was measured by BCA protein assay kit.

Fc gamma receptor IIIA (RIIIA), also called CD16a, is an activating natural killer (NK) cell receptor that binds the Fc portion of immunoglobulin G (IgG) antibodies and is responsible for eliciting a host defense against microbial pathogens (1). Fc gamma RIIIA/CD16a belongs to the Fc gamma RIII (CD16) subclass of Fc gamma receptors (1,2). The two other subclasses of receptors are Fc gamma RI (CD64) and Fc gamma RII (CD32) (1,2). The two form of Fc gamma RIII are Fc gamma RIIIA (CD16a) and Fc gamma RIIIB (CD16b), which are encoded by two different homologous genes, FCGR3A and FCGR3B, respectively (1-3). The human Fc gamma RIIIA protein is 254 amino acids (aa) in length with a theoretical molecular weight (MW) of 29 kDa (1,4,5). CD16a contains five glycosylation sites, two disulfide bonds, and two Ig-like C2 domains (4). Fc gamma RIIIA/CD16a is expressed as a transmembrane protein on NK cells and on a subset of monocytes, macrophages, CD4+ T cells, basophils, and mast cells (1-3). The soluble form of CD16 (sCD16) is often produced following exposure to inflammatory signals and protein shedding via metalloproteinases (3). Reduced sCD16 levels have been found in patients with multiple myeloma (3).

Activating NK cell receptor function has been harnessed for its potential in tumor immunotherapy (5). One immunotherapy strategy is using bi- and tri-specific NK cell engagers (BiKE and TriKE) to target the Fc gamma RIIIA/CD16a receptor with tumor-associated antigens to stimulate a cytotoxic response and mount an attack on tumor cells (5). CD16a is also capable of antibody dependent cellular cytotoxicity (ADCC) through recognition of antibodies bound to target cells (5-6). CD16-induced NK cell activation allows for NK co-receptor expression including stimulatory receptors like CD137 or inhibitory receptors like TIGIT and PD-1, which serve as additional regulatory checkpoints during ADCC (6). Therapeutic antibodies for cancer treatment like rituximab or trastuzumab can be recognized by Fc gamma RIIIA/CD16a to activate NK cell-mediated killing of tumor cells (5-6).

References

1. Fossati, G., Bucknall, R. C., & Edwards, S. W. (2001). Fcgamma receptors in autoimmune diseases. European Journal of Clinical Investigation, 31(9), 821-831. https://doi.org/10.1046/j.1365-2362.2001.00881.x

2. Patel, K. R., Roberts, J. T., & Barb, A. W. (2019). Multiple Variables at the Leukocyte Cell Surface Impact Fc gamma Receptor-Dependent Mechanisms. Frontiers in Immunology, 10, 223. https://doi.org/10.3389/fimmu.2019.00223

3. Moldovan, I., Galon, J., Maridonneau-Parini, I., Roman Roman, S., Mathiot, C., Fridman, W. H., & Sautes-Fridman, C. (1999). Regulation of production of soluble Fc gamma receptors type III in normal and pathological conditions. Immunology Letters, 68(1), 125-134. https://doi.org/10.1016/s0165-2478(99)00041-3

4. Uniprot (P08637)

5. Sivori, S., Pende, D., Quatrini, L., Pietra, G., Della Chiesa, M., Vacca, P., Tumino, N., Moretta, F., Mingari, M. C., Locatelli, F., & Moretta, L. (2021). NK cells and ILCs in tumor immunotherapy. Molecular Aspects of Medicine, 80, 100870. https://doi.org/10.1016/j.mam.2020.100870

6. Muntasell, A., Ochoa, M. C., Cordeiro, L., Berraondo, P., Lopez-Diaz de Cerio, A., Cabo, M., Lopez-Botet, M., & Melero, I. (2017). Targeting NK-cell checkpoints for cancer immunotherapy. Current Opinion in Immunology, 45, 73-81. https://doi.org/10.1016/j.coi.2017.01.003

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Lysates are guaranteed for 6 months from date of receipt.

Array NBL1-10658

• Fc gamma RIIIA/CD16a Antibodies
• Fc gamma RIIIA/CD16a ELISA Kit
• Fc gamma RIIIA/CD16a Lysates
• Fc gamma RIIIA/CD16a Protein
• Fc gamma RIIIA/CD16a Proteins and Enzymes