Journal
FRONTIERS IN IMMUNOLOGY
Volume 10, Issue -, Pages -Publisher
FRONTIERS MEDIA SA
DOI: 10.3389/fimmu.2019.00630
Keywords
T cell receptor; co-receptor; PD-1; CD28; ICOS; cytokine production; follicular helper T cell
Categories
Funding
- Core Research for Evolutional Science and Technology Program of the Japan Science and Technology Agency
- Basic Science and Platform Technology Program for Innovative Biological Medicine of the Japan Agency for Medical Research and Development [JP18am0301007]
- Japan Society for the Promotion of Science [JP18H05417]
- JSPS [JP16J08600]
- Katsunuma scholarship
Ask authors/readers for more resources
Cancer-immunotherapy targeting programmed cell death 1 (PD-1) activates tumor-specific T cells and provides clinical benefits in various cancers. However, the molecular basis of PD-1 function is still enigmatic. Especially, it is unclear which signaling pathway PD-1 primarily targets. Besides, the capacity of PD-1 to inhibit the T cell receptor (TCR)-dependent activation of T cells in the presence of co-stimulation is also controversial. Here we used co-culture systems of T cells and antigen-presenting cells with targeted deletion and overexpression of co-receptors and ligands and examined the inhibitory potency of PD-1 against T cell activation upon TCR stimulation with CD28 and ICOS co-stimulation. As an unambiguous criterion of T cell activation, we used the acquisition of cytokine production capacity, which represents one of the most important functions of T cells. PD-1 inhibited functional T cell activation upon TCR stimulation in the absence as well as in the presence of CD28 co-stimulation, indicating that PD-1 can directly inhibit TCR signal. Notably, CD28 co-stimulation rather attenuated the efficiency of PD-1 in inhibiting TCR-dependent functional T cell activation. In addition, PD-1 inhibited TCR-dependent functional T cell activation with ICOS co-stimulation as efficiently as that with CD28 co-stimulation. Furthermore, we found that the maintenance of antigen-induced follicular helper T (T-FH) cells that required ICOS co-stimulation was persistently restrained by PD-1 in vivo. These findings indicate that PD-1 primarily targets TCR signal in the inhibition of functional T cell activation. Thus, PD-1 functions as the rheostat of T cell activation rather than an inhibitor of a specific stimulatory co-receptor.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available