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Qdot™ Antibody (Ab) conjugates possess a bright fluorescence emission that makes them well suited for the detection of low-abundance extracellular proteins. Approximately the same size as R-phycoerythrin (R-PE) and compatible with existing organic fluorophore conjugates, Qdot™ Ab conjugates can be excited with any wavelength below their emission maximum, but are best excited by UV or violet light. The narrow, symmetric emission profiles of Qdot Ab conjugates allow for minimal compensation when using a single excitation source, and the very long stoke shifts enable better, more efficient multicolor assays using the 405 nm violet laser. Available in multiple colors for use in flow cytometry, these advantages make Qdot Ab conjugates powerful tools for antibody labeling and staining. Staining: Stain cells in any standard staining buffer, such as phosphate buffered saline (PBS) with 1% bovine serum albumin (BSA). We recommend analysis of cells within 18 hours of staining. If dilute reagent is used, dilute only the quantity of reagent to be used within one day. Qdot Ab conjugates may be mixed with other antibodies, but use the diluted conjugates on the day of dilution. Qdot Ab conjugates can be used for surface staining applications with most conventional sample preparation reagents, such as Cal-Lyse™ Lysing Solution and FIX & PERM™ reagents, with minimal effect on fluorescence. We have observed some batches of BD FACS™ Lysing Solution to interfere with Qdot Ab conjugate fluorescence. Each lot has been tested by flow cytometry using human peripheral blood leukocytes. This antibody recognizes the CD8 antigen, also known as T8 and Lyt2, and recognizes the alpha chain alone as well as the alpha-beta heterodimer. The isotype control for this antibody is mouse IgG2a, Cat. No. Q10015.
Instrument setup: Qdot Ab conjugates are excited optimally with UV or 405 nm light, although excitation can be obtained with any wavelength below the emission maximum of a given Qdot™ nanocrystal, such as with a 488-nm laser. Qdot Ab conjugates can be used on cytometers that do not have UV or violet excitation sources as long as they have appropriate emission filters. Make sure the cytometer has an appropriate emission filter for the Qdot Ab conjugate being used; alternate filters can be used as long as they capture the emission maximum, but filter width impacts spectral overlap corrections. And be sure to check for Qdot Ab conjugate emission in any channel that can capture nanocrystal emission off of other lasers on the cytometer. For Cat. No. Q10055: peak excitation 405 (488) nm/peak emission 655 nm; recommended filter 655/20 nm.
Store reagents at 2-8°C in the dark. Do not freeze. Because Qdot nanocrystals are conjugated to biological materials, some loss of activity may be observed with prolonged storage. When stored as instructed, expires six months from date of receipt unless otherwise indicated on product label. Qdot Ab conjugates are photostable, and do not need to be protected from light. However, if using Qdot Ab conjugates in combination with conventional fluorochrome conjugated antibodies, minimize light exposure during handling, incubation with cells, and prior to analysis. The Qdot Ab conjugates contain cadmium and selenium in an inorganic crystalline form. Dispose of the material in compliance with all applicable local, state, and federal regulations for disposal of these classes of material. For more information on the composition of these materials, consult the Safety Data Sheets (SDSs).
Cluster of differentiation 8 (CD8), a type I transmembrane glycoprotein of the immunoglobulin family of receptors, plays an integral role in signal transduction, and T cell differentiation and activation. CD8 is predominantly expressed on T cells as a disulfide-linked heterodimer of CD8alpha and CD8beta, where it functions as a co-receptor, along with T cell receptor (TCR), for major histocompatibilty complex class I (MHC-I) molecules; whereas its counterpart, CD4, acts as a co-receptor for MHC-II molecules. CD8 exists on the cell surface, where the CD8alpha chain is essential for binding to MHC-I. CD8 is also expressed on a subset of T cells, NK cells, monocytes and dendritic cells as disulfide-linked homodimers of CD8alpha. Ligation of MHC-I/peptide complexes presented by antigen-presenting cells (APCs), triggers the recruitment of lymphocyte-specific protein tyrosine kinase (Lck), which leads to lymphokine production, motility and cytotoxic T lymphocyte (CTL) activation. Once activated, CTLs play a crucial role in the clearance of pathogens and tumor cells. Differentiation of naive CD8+ T cells into CTLs is strongly enhanced by IL-2, IL-12 and TGF-beta1.
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Protein Aliases: CD8 antigen, alpha polypeptide (p32); CD8 antigen, beta polypeptide 1 (p37); CD8a; CD8alpha; CD8b; CD8beta; fCD8; Leu-2; leu-2a; Leu2 T-lymphocyte antigen; OKT8 T-cell antigen; T cell co-receptor; T lymphocyte surface glycoprotein beta chain; T-cell antigen Leu2; T-cell surface glycoprotein CD8 alpha chain; T-cell surface glycoprotein CD8 beta chain; T-lymphocyte differentiation antigen T8/Leu-2; T8 T-cell antigen
Gene Aliases: CD8; CD8A; CD8B; CD8B1; LEU2; LY3; LYT3; MAL; p32; P37
UniProt ID: (Human) P01732, (Human) P10966
Entrez Gene ID: (Human) 925, (Human) 926
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