Clone TG1 is the first monoclonal antibody detecting TIGIT (T cell immunoreceptor with Ig and ITIM domains) in routine formalin-fixed paraffin-embedded tissue specimen. It has been validated for the identification of TIGIT positive T-cells infiltrating human tumors in order to allow the detection of TIGIT in the tumor microenvironment under pathological conditions.
TIGIT (T-cell immunoreceptor with Ig and ITIM domains) is a member of the poliovirus receptor (PVR) family and acts as an im-mune checkpoint protein expressed on subsets of T lymphocytes. The expression of TIGIT has been reported on NK cells, regu-latory T cells, follicular T helper cells, memory CD4+ T cells, and CD8+ T cells, but it is not expressed on B cells or naive CD4+ T cells. TIGIT may be upregulated on naive CD4+ T cells upon activation. TIGIT has been shown to be upregulated on T cells in multiple cancer models. The ligands CD155 and CD112 are also highly expressed on dendritic cells and macrophages in several types of cancer. Additionally, TIGIT expression is highly correlated with the expression of other coinhibitory molecules, including PD-1. In addition to directly inhibiting cytotoxic T-cell activity, TIGIT can foster an immunosuppressive microenvironment through its impact on other immune cells, for example, by binding to CD155 on the surface of dendritic cells or by manipulating NK cell activity. TIGIT inhibiting drugs are currently being developed. Immunohistochemical application of monoclonal antibody TG1 may provide valuable information for clinical research and potential therapeutic interventions specifically targeting the TIGIT-related tumor immunology checkpoint.
References for Clone TG1
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- Annibali, O., Bianchi, A., Grifoni, A. et al. A novel scoring system for TIGIT expression in classic Hodgkin lymphoma. Sci Rep 11, 7059. https://doi: 10.1038/s41598-021-86655-8 (2021)
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- Li W et al. Expression of the immune checkpoint receptor TIGIT in Hodgkin’s lymphoma. BMC Cancer 2018, 18:1209, https://doi.org/10.1186/s12885-018-5111-1
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