QdotTM 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, QdotTM 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 and 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. 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. Q10007: 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).
CD4 antigen, also known as T4 and L3T4, is involved in the recognition of the type II MHC antigen. CD4 serves as a co-receptor during T cell activation through the binding of MHC Class II molecules. CD4 is expressed on helper T cells, thymocyte subsets, and to a lesser extent on peripheral blood monocytes. It is also a receptor for HIV. The cytoplasmic portion of CD4 is associated with p56lck tyrosine kinase. CD4 expression is commonly found in human lymph nodes and tonsils. Leukocyte Workshop Status: Leukocyte Typing V.
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Protein Aliases: CD4; CD4 antigen (p55); CD4 antigen p55; CD4 receptor; T-cell surface antigen T4/Leu-3; T-cell surface glycoprotein CD4
Gene Aliases: CD4; CD4mut
UniProt ID: (Human) P01730
Entrez Gene ID: (Human) 920