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C57Bl/6 splenocytes were stained with 0.06 ug APC Anti-Mouse CD4 (20-0041) (solid line) or 0.06 ug APC Rat IgG2b isotype control (dashed line).

APC Anti-Mouse CD4 (GK1.5)

SKU 20-0041-U025
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The GK1.5 antibody reacts with mouse CD4, a 55 kDa protein which acts as a co-receptor for the T cell receptor (TCR) in its interaction with MHC Class II molecules on antigen-presenting cells. The extracellular domain of CD4 binds to the beta-2 domain of MHC Class II, while its cytoplasmic tail provides a binding site for the tyrosine kinase lck, facilitating the signaling cascade that initiates T cell activation. CD4 is typically expressed on thymocytes, certain mature T cell populations such as Th17 and T regulatory (Treg) cells, as well as on dendritic cells.

The GK1.5 antibody is widely used as a phenotypic marker for CD4 expression. If used together, the GK1.5 antibody and an alternative antibody, Anti-Mouse CD4 clone RM4-5, will “compete” for binding, i.e. RM4-5 is able to block GK1.5 binding to cells. In contrast, the Anti-Mouse CD4 clone RM4-4 does not block binding of the GK1.5 antibody to cells (Arora S et al. 2006. Infect. Immun. 74: 4339-4348). The GK1.5 antibody is also reported to be cross-reactive with Syrian hamster CD4.

Recent Publications:

Kim IS, Gao Y, Welte T, et al. Immuno-subtyping of breast cancer reveals distinct myeloid cell profiles and immunotherapy resistance mechanisms. Nat Cell Biol. 2019;21(9):1113-1126. doi:10.1038/s41556-019-0373-7.

» View on PubMed

Cruz-Adalia A, Ramirez-Santiago G, Torres-Torresano M, Garcia-Ferreras R and Veiga Chacon E. 2016. J Vis Exp. (107). doi: 10.3791/52976. (Flow Cytometry)

Name APC Anti-Mouse CD4 (GK1.5)
Cat. No. 20-0041
Alternative Names L3T4, T4
Gene ID 12504
Clone GK1.5
Isotype Rat IgG2b, κ
Reactivity Mouse
Cross Reactivity Syrian Hamster
Format APC
Application Flow Cytometry
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