T cell co-stimulatory receptor pathway

The T cell co-stimulatory receptor pathway refers to a network of surface receptor-ligand interactions required for full T cell activation in the immune response. T cell activation classically requires two signals: antigen recognition by the T cell receptor (TCR) and a secondary, antigen-independent co-stimulatory signal. Canonical co-stimulatory receptors include CD28 (binding CD80/CD86 on antigen-presenting cells), ICOS, OX40, 4-1BB (CD137), CD27, and others, with their ligands mainly expressed on antigen-presenting cells. These co-stimulatory molecules belong primarily to the Ig superfamily (e.g., CD28 family) and the tumor necrosis factor receptor (TNFR) superfamily (e.g., OX40, 4-1BB, CD27)[1][3][7]. Co-stimulation is required for T cells to avoid anergy or apoptosis, to proliferate, survive, produce cytokines, and differentiate into effector and memory subsets[2][3][6]. Dysregulation of this pathway drives diseases such as autoimmunity, cancer, and transplant rejection. Therapeutic strategies targeting components of the T cell co-stimulatory and co-inhibitory pathways include immune checkpoint inhibitors (e.g., anti-CTLA-4, anti-PD-1 antibodies), fusion proteins blocking co-stimulation (abatacept, belatacept), and agonistic antibodies enhancing co-stimulatory signals (e.g., anti-OX40, anti-4-1BB)[2][7][8]. This entry is not a single molecular target but a pathway involving multiple interacting receptor-ligand pairs, so “T cell co-stimulation pathway” itself is not considered a valid drug target; individual co-stimulatory receptors within this pathway are true therapeutic targets. Note: - The name “T cell co-stimulation pathway” is not a canonical molecular target but a functional/process pathway; for structured curation, entries should focus on specific receptors (e.g., CD28, OX40, 4-1BB) rather than the pathway as a whole. - See individual co-stimulatory/co-inhibitory receptors for target-level structured data[1][3][7][8].

Other names

T cell costimulation pathwayT cell co-signaling pathwayT cell co-stimulationcostimulatory signaling in T cells

Blockade of co-stimulatory receptor-ligand interaction (e.g., CD28-CD80/CD86 by abatacept/belatacept), Immune checkpoint blockade (e.g., anti-CTLA-4, anti-PD-1), Agonism of co-stimulatory receptors (e.g., OX40, 4-1BB agonists)