TDS | SDS

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:

Prakhar P, Gonzalez V, Park JH. High-yield enrichment of mouse small intestine intraepithelial lymphocytes by immunomagnetic depletion of EpCAM+ cells. STAR Protoc. 2022 Feb 25;3(1):101207. doi: 10.1016/j.xpro.2022.101207. PMID: 35243383; PMCID: PMC8885746.

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Chun N, Ang RL, Chan M, Fairchild RL, Baldwin Iii WM, Horwitz JK, Gelles JD, Chipuk JE, Kelliher MA, Pavlov VI, Li Y, Homann D, Heeger PS, Ting AT. T cell-derived tumor necrosis factor induces cytotoxicity by activating RIPK1-dependent target cell death. JCI Insight. 2021 Nov 9:e148643. doi: 10.1172/jci.insight.148643. Epub ahead of print. PMID: 34752416.

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Li C, Park JH. Assessing IL-2-Induced STAT5 Phosphorylation in Fixed, Permeabilized Foxp3+ Treg Cells by Multiparameter Flow Cytometry. STAR Protoc. 2020 Dec 1;1(3):100195. doi: 10.1016/j.xpro.2020.100195. PMID: 33377089; PMCID: PMC7757559.

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