CD4 is a 55 kD protein also known as L3T4 or T4. It is a member of the Ig superfamily, primarily expressed on most thymocytes, a subset of T cells, and weakly on macrophages and dendritic cells. It acts as a coreceptor with the TCR during T cell activation and thymic differentiation by binding MHC class II and associating with the protein tyrosin kinase, lck.
The antibody was purified by affinity chromatography and conjugated with Brilliant Violet 750™ under optimal conditions. The solution is free of unconjugated Brilliant Violet 750™ and unconjugated antibody.
Concentration
0.2 mg/ml
Storage & Handling
The antibody solution should be stored undiluted between 2°C and 8°C, and protected from prolonged exposure to light. Do not freeze.
Each lot of this antibody is quality control tested by immunofluorescent staining with flow cytometric analysis. For flow cytometric staining, the suggested use of this reagent is ≤ 0.25 µg per million cells in 100 µl volume. It is recommended that the reagent be titrated for optimal performance for each application.
Brilliant Violet 750™ excites at 405 nm and emits at 750 nm. The bandpass filter 780/60 nm is recommended for detection, although filter optimization may be required depending on other fluorophores used. Be sure to verify that your cytometer configuration and software setup are appropriate for detecting this channel. Refer to your instrument manual or manufacturer for support. Brilliant Violet 750™ is a trademark of Sirigen Group Ltd.
This product is subject to proprietary rights of Sirigen Inc. and is made and sold under license from Sirigen Inc. The purchase of this product conveys to the buyer a non-transferable right to use the purchased product for research purposes only. This product may not be resold or incorporated in any manner into another product for resale. Any use for therapeutics or diagnostics is strictly prohibited. This product is covered by U.S. Patent(s), pending patent applications and foreign equivalents.
Excitation Laser
Violet Laser (405 nm)
Application Notes
Additional reported applications (for the relevant formats) include: blocking of CD4+ T cell activation1,4,11, thymocyte costimulation3, in vitro and in vivo depletion2,5-8, blocking of egg-sperm cell adhesion1,4, immunohistochemical staining of acetone-fixed frozen sections9,10, and immunoprecipitation1,2. The GK1.5 antibody is able to block CD4 mediated cell adhesion and T cell activation. Binding of GK1.5 antibody to CD4 T cells can be blocked by RM4-5 antibody (Cat. No. 100506), but not RM4-4 antibody (Cat. No. 116002). The LEAF™ purified antibody (Endotoxin <0.1 EU/μg, Azide-Free, 0.2 μm filtered) is recommended for functional assays (Cat. No. 100416). For in vivo studies or highly sensitive assays, we recommend Ultra-LEAF™ purified antibody (Cat. No. 100442) with a lower endotoxin limit than standard LEAF™ purified antibodies (Endotoxin <0.01 EU/µg).
Application References
(PubMed link indicates BioLegend citation)
Dialynas DP, et al. 1983. J. Immunol. 131:2445. (Block, IP)
Dialynas DP, et al. 1983. Immunol. Rev. 74:29. (IP, Deplete)
Wu L, et al. 1991. J. Exp. Med. 174:1617. (Costim)
Godfrey DI, et al. 1994. J. Immunol. 152:4783. (Block)
Gavett SH, et al. 1994. Am. J. Respir. Cell. Mol. Biol. 10:587. (Deplete)
Schuyler M, et al. 1994. Am. J. Respir. Crit. Care Med. 149:1286. (Deplete)
Ghobrial RR, et al. 1989. Clin. Immunol. Immunopathol. 52:486. (Deplete)
Israelski DM, et al. 1989. J. Immunol. 142:954. (Deplete)
Zheng B, et al. 1996. J. Exp. Med. 184:1083. (IHC)
Frei K, et al. 1997. J. Exp. Med. 185:2177. (IHC)
Felix NJ, et al. 2007. Nat. Immunol. 8:388. (Block)
1. Barclay A, et al. 1997. The Leukocyte Antigen FactsBook Academic Press.
2. Bierer BE, et al. 1989. Annu. Rev. Immunol. 7:579.
3. Janeway CA. 1992. Annu. Rev. Immunol. 10:645.
I am unable to see expression of T cell markers such as CD3 and CD4 post activation.
TCR-CD3 complexes on the T-lymphocyte surface are rapidly downregulated upon activation with peptide-MHC complex, superantigen or cross-linking with anti-TCR or anti-CD3 antibodies. PMA/Ionomycin treatment has been shown to downregulate surface CD4 expression. Receptor downregulation is a common biological phenomenon and so make sure that your stimulation treatment is not causing it in your sample type.
This data display is provided for general comparisons between formats.
Your actual data may vary due to variations in samples, target cells, instruments and their settings, staining conditions, and other factors.
If you need assistance with selecting the best format contact our expert technical support team.
