The 4E5 monoclonal antibody specifically recognizes Ly-49D, which is expressed on subsets of natural killer (NK) cells in C57BL/6, C3H/He (at a very low frequency), and SJL, but not DBA/2, AKR, CBA/J, or BALB/c mice. Unlike Ly-49D antigen has not been betected on NK-1.1+ (or DX5+) T cells. In 129/J mice, the 4E5 antibody cross-reacts with Ly-49O, Ly-49R, and Ly-49V. The Ly-49 family of NK-cell receptors, members of the C-type lectin superfamily, are disulfide-linked type-II transmembrane protein homodimers with extracellular carbohydrate-recognition domains, which bind to MHC class I alloantigens. The Ly-49 family members are expressed independently, such that an individual NK or T cell may display more than one class of Ly-49 receptor homodimers. Ly-49D weakly binds to MHC class I antigens of the k halpotype, and Ly-49D+ IL-2-activated NK cells lyse target cells expressing H-2[a], H-2[b], H-2[d], H-2[k], H-2[p], H-2[q], and H-2[s] and the CHO (Chinese hamster ovary) cell line. Ly-49D+ cells mediate allogenic resistance to H-2d bone marrow transplantation. In vitro studies suggest that the Ly-49D receptor mediates activation of NK-cell cytolytic activity via tyrosine phosphorylation of their ITIMs (Immunoreceptor Tyrosine-based Inhibitory Motifs). Molecular differences between the Ly-49D stimulatory receptor and the inhibitory members of the Ly-49 family include the absence of an ITIM in Ly-49D, the lack of phosphorylation of Ly-49D in activated NK cells, and the association of a novel tyrosine-phosphorylated protein (pp16) with Ly-49D in activated NK cells. Ly-49O and Ly-49V are closely related to Ly-49A[B6] and, like Ly-49A, have ITIM domains. Ly-49O- and Ly-49V-transfected 293T (human kidney epithelial) cells bind tetramers of H-2D[b], D[b], D[k], and L[d]. In addition, the Ly-49V-transfected cells also bind K[b], K[d], and K[k]. Ly-49R is closely related to Ly-49D[B6] and is putative activating receptor due to its lack of an ITIM domain. Ly-49R-transfected 293T cells bind soluble tetramers of H-2D[b], D[d], D[k], and L[d].
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.
