T-Cell Co-Stimulation & Agonist Checkpoint Pathway
T-cell co-stimulation & agonist checkpoints. The "accelerator" side of the immune synapse: co-stimulatory (CD28-family) and TNF-receptor-superfamily signals that amplify T-cell activation. Antigen-presenting cell at the top, T cell below, signalling cascading down to the nucleus. Nodes are colour-coded by protein class (see Legend); click any protein to open the matching Assay Genie In Vivo functional-grade antibody (surface targets) or ELISA kit (signalling proteins).
Full T-cell activation requires more than antigen recognition. Signal 1 is delivered by the TCR/CD3 complex reading peptide-MHC; Signal 2 is co-stimulation. The prototypic co-stimulator CD28 and its relative ICOS (CD278) engage CD80/CD86 and ICOS-ligand to drive PI3K→AKT→mTOR, boosting metabolism, survival and proliferation.
A second wave of co-stimulation comes from the TNF-receptor superfamily — 4-1BB (CD137), CD27 and CD40 (with OX40 and GITR). These recruit TRAF adaptors that activate both the canonical (IKK→RelA/p65) and non-canonical (NIK→RelB) NF-κB pathways, inducing survival genes such as Bcl-xL and programming effector and memory differentiation. CD40 ligation also licenses the antigen-presenting cell, upregulating CD80/86 and IL-12.
Agonist antibodies mimic these ligands: Assay Genie In Vivo functional-grade (low / ultra-low endotoxin) anti-4-1BB, anti-CD40, anti-CD70 and anti-ICOS antibodies are used to amplify anti-tumour T-cell responses in vivo, and pair with checkpoint blockade in combination studies. For research use only; not for diagnostic or therapeutic procedures. Mouse targets shown.
Every protein node links to a product: surface co-stimulators open Assay Genie In Vivo functional-grade agonist antibodies; signalling proteins open the matching ELISA kit.