C57BL/6 mouse splenocytes were stained with CD4 (clone GK1.5) PE/Cyanine7 (filled histogram) or rat IgG2b, κ PE/Cyanine7 isotype control (open histogram).
C57BL/6 mouse splenocytes were stained with CD4 (clone GK1.5) PE/Cyanine7 (filled histogram) or rat IgG2b, κ PE/Cyanine7 isotype control (open histogram).
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.
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 106 cells in 100 µl volume. It is recommended that the reagent be titrated for optimal performance for each application.
Excitation Laser
Blue Laser (488 nm) Green Laser (532 nm)/Yellow-Green Laser (561 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, immunoprecipitation1,2, and spatial biology (IBEX)12,13. 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, but not RM4-4 antibody. 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).
Additional Product Notes
BioLegend is in the process of converting the name PE/Cy7 to PE/Cyanine7. The dye molecule remains the same, so you should expect the same quality and performance from our PE/Cyanine7 products. Please contact Technical Service if you have any questions.
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)
Radtke AJ, et al. 2020. Proc Natl Acad Sci U S A. 117:33455-65. (SB) PubMed
Radtke AJ, et al. 2022. Nat Protoc. 17:378-401. (SB) PubMed
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.
Login / Register 
Follow Us