Description
The CG4.rMab is a recombinant monoclonal antibody that was derived from CG4 hybridoma cells. The CG4.rMab specifically binds to human G-protein coupled receptor 56 (GPR56) like the conventional CG4 antibody and performs like the CG4 antibody when used to stain cells and analyze them by flow cytometry. GPR56 is also known as adhesion G-protein coupled receptor G1 (ADGRG1), or TM7XN1. GPR56 is a ~15kDa G protein-coupled receptor encoded by ADGRG1 which belongs to the adhesion-GPCR family that comprises 33 members in human. The extracellular region contains a mucin-like domain followed by a membrane proximal GPCR-autoproteolysis inducing (GAIN) domain, seven transmembrane regions and a cytoplasmic tail. The constitutive self-cleavage at the proteolytic site gives rise to a membrane spanning (C-terminal fragment or CTF) and an extracellular (N-terminal fragment or NTF) subunit that remain noncovalently bound, leading to the expression of a heterodimeric receptor at the cell surface. GPR56 is widely expressed with the highest levels of messenger found in the brain, heart, and thyroid gland. Recently, GPR56 was found to be variably expressed on platelets, cytotoxic NK cells and T lymphocytes including CD4+, CD8+, and γδ T cells. It was shown that GPR56 functions as an inhibitory receptor on NK cells through interaction with CD81. While GPR56 NTF associates with Tissue transglutaminase 2 and Collagen III (α-1), GPR56 CTF can recruit Gα proteins leading to the activation of mTOR and RhoA signaling pathways. GPR56 has been implicated in cell-cell interactions, adhesion, migration, and regulation of cell proliferation and survival of various cell types. New evidence also shows a role of GPR56 in tumor progression. Recently, the CG4 antibody was found to activate GPR56 in melanoma cells leading to an increase of IL-6 secretion, in a CD9/CD81-dependent manner.
Bead-based compensation or unmixing controls, such as BD® CompBeads or BD™ SpectraComp™, can be used as surrogates to assess fluorescence spillover when bound to fluorochrome-conjugated antibodies. Although these beads have spectral properties similar to cells, variations in spectral emission may occur, resulting in differing spillover values compared to biological controls. Therefore, it is considered best practice to compare the spillover obtained from cells and bead-based controls when using BD® CompBeads or BD™ SpectraComp™ for the first time, to ensure they are appropriate for the intended application.
Store undiluted at 4°C and protected from prolonged exposure to light. Do not freeze. The monoclonal antibody was purified from tissue culture supernatant or ascites by affinity chromatography. The antibody was conjugated to the dye under optimum conditions that minimize unconjugated dye and antibody.
1. Please refer to www.bdbiosciences.com/us/s/resources for technical protocols.
2. Please refer to http://regdocs.bd.com to access safety data sheets (SDS).
3. For U.S. patents that may apply, see bd.com/patents.
4. Caution: Sodium azide yields highly toxic hydrazoic acid under acidic conditions. Dilute azide compounds in running water before discarding to avoid accumulation of potentially explosive deposits in plumbing.
5. Since applications vary, each investigator should titrate the reagent to obtain optimal results.
6. The production process underwent stringent testing and validation to assure that it generates a high-quality conjugate with consistent performance and specific binding activity. However, verification testing has not been performed on all conjugate lots.
7. When using high concentrations of antibody, background binding of this dye to erythroid fragments produced by ammonium chloride-based lysis, such as with BD Pharm Lyse™ Lysing Buffer (Cat. No. 555899), has been observed when the antibody conjugate was present during the lysis procedure. This may cause nonspecific staining of target cells, such as leukocytes, which have bound the resulting erythroid fragments. This background can be mitigated by any of the following: titrating the antibody conjugate to a lower concentration, fixing samples with formaldehyde, or removing erythrocytes before staining (eg, gradient centrifugation or pre-lysis with wash). This background has not been observed when cells were lysed with BD FACS™ Lysing Solution (Cat. No. 349202) after staining.
8. For fluorochrome spectra and suitable instrument settings, please refer to our Multicolor Flow Cytometry web page at www.bdbiosciences.com/colors.
9. An isotype control should be used at the same concentration as the antibody of interest.
10. Cy is a trademark of Global Life Sciences Solutions Germany GmbH or an affiliate doing business as Cytiva.
11. Please observe the following precautions: We recommend that special precautions be taken (such as wrapping vials, tubes, or racks in aluminum foil) to protect exposure of conjugated reagents, including cells stained with those reagents, to any room illumination. Absorption of visible light can significantly affect the emission spectra and quantum yield of tandem fluorochrome conjugates.
12. Tandem fluorochromes contain both an energy donor and an energy acceptor. Although every effort is made to minimize the lot-to-lot variation in the efficiency of the fluorochrome energy transfer, differences in the residual emission from the donor may be observed. Additionally, multi-laser cytometers may directly excite both the donor and acceptor fluorochromes. Therefore, we recommend for every tandem conjugate, a matched individual single-stain control be acquired for generating a compensation or spectral unmixing matrix.
13. Human donor specific background has been observed in relation to the presence of anti-polyethylene glycol (PEG) antibodies, developed as a result of certain vaccines containing PEG, including some COVID-19 vaccines. We recommend use of BD Horizon Brilliant™ Stain Buffer in your experiments to help mitigate potential background. For more information visit https://www.bdbiosciences.com/en-us/support/product-notices.
