Description
The 341 monoclonal antibody specifically recognizes the β chain of the CD8 antigen on most thymocytes and a subpopulation of mature T lymphocytes (ie, MHC class I-restricted T cells, including most T suppressor/cytotoxic cells). The CD8 α and β chains (CD8a and CD8b, respectively) form a heterodimer on the surface of most thymocytes and thymus-dependent T suppressor/cytotoxic cells, whereas intestinal intraepithelial lymphocytes, many CD8+ T cells of athymic rats, many activated CD4+ T cells, and most NK cells express CD8a without CD8b. It has been suggested that the expression of the CD8a/CD8b heterodimer is restricted to thymus-derived T lymphocytes. CD8 is an antigen co-receptor on the T cell surface which interacts with MHC class I molecules on antigen-presenting cells. It participates in T-cell activation through its association with the T-cell receptor complex and protein tyrosine kinase lck. Macrophages have also been reported to express CD8 α and β chains, which are involved in signal transduction. The 341 mAb blocks proliferative and cytotoxic in vitro responses of CD8+ effectors to allogeneic cells.
BD® CompBeads can be used as surrogates to assess fluorescence spillover (compensation). When fluorochrome conjugated antibodies are bound to BD® CompBeads, they have spectral properties very similar to cells. However, for some fluorochromes there can be small differences in spectral emissions compared to cells, resulting in spillover values that differ when compared to biological controls. It is strongly recommended that when using a reagent for the first time, users compare the spillover on cells and BD® CompBeads to ensure that BD® CompBeads are appropriate for your specific cellular 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. 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.
2. Researchers should determine the optimal concentration of this reagent for their individual applications.
3. 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.
4. Please refer to www.bdbiosciences.com/us/s/resources for technical protocols.
5. Please observe the following precautions: Absorption of visible light can significantly alter the energy transfer occurring in any tandem fluorochrome conjugate; therefore, we recommend that special precautions be taken (such as wrapping vials, tubes, or racks in aluminum foil) to prevent exposure of conjugated reagents, including cells stained with those reagents, to room illumination.
6. An isotype control should be used at the same concentration as the antibody of interest.
7. 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.
8. Please refer to http://regdocs.bd.com to access safety data sheets (SDS).
9. For fluorochrome spectra and suitable instrument settings, please refer to our Multicolor Flow Cytometry web page at www.bdbiosciences.com/colors.
10. Since applications vary, each investigator should titrate the reagent to obtain optimal results.
11. Cy is a trademark of Global Life Sciences Solutions Germany GmbH or an affiliate doing business as Cytiva.
