T-cell activation machinery downstream of the Chimeric Antigen Receptor (CAR signaling pathway)

The T-cell activation machinery downstream of the Chimeric Antigen Receptor (CAR) refers to the intracellular signaling network that converts antigen binding into T-cell effector responses. This machinery typically utilizes the CD3-zeta (CD3ζ) signaling domain and costimulatory domains (e.g., CD28 or 4-1BB) to recruit and activate proximal tyrosine kinases like Lck and ZAP-70 (Wu et al., 2020, Molecular Cancer; Salter et al., 2018, Immunity). These kinases initiate a cascade involving adaptor proteins such as LAT and SLP-76, which further activate downstream pathways including the PLC-gamma/NFAT, Ras/MAPK, and PI3K/Akt/NF-kappaB pathways (Salter et al., 2018, Immunity; Mestermann et al., 2019, Science Translational Medicine). These signals are essential for CAR-T cell proliferation, cytokine production, and the release of cytotoxic granules like perforin and granzyme (Wu et al., 2020, Molecular Cancer; Labanieh et al., 2018, Nature Biomedical Engineering). Because overactivation of this machinery can lead to severe toxicities like cytokine release syndrome (CRS), it has become a focus for pharmacological intervention. For instance, the Src-family kinase inhibitor dasatinib can be used as a "safety switch" to temporarily halt CAR-T cell activity by inhibiting Lck-mediated phosphorylation (Mestermann et al., 2019, Science Translational Medicine; Weber et al., 2021, Science). Understanding this machinery is crucial for the design of next-generation CARs with tuned signaling kinetics to prevent T-cell exhaustion and improve therapeutic durability (Weber et al., 2021, Science).

Other names

CAR-T signaling cascadeCAR-mediated T-cell activation pathwayDownstream CAR signaling machinery

Pharmacological inhibition of key signaling nodes within the CAR-mediated cascade, such as Lck, ZAP-70, or calcineurin, to reversibly or irreversibly suppress T-cell activation, proliferation, and cytokine release.