NK cell exhaustion is caused by chronic exposure to activating stimuli during viral infection, tumorigenesis, and prolonged cytokine treatment. Evidence suggests that exhaustion may play a role in disease progression. However, relative to T cell exhaustion, the mechanisms underlying NK cell exhaustion and methods of reversing it are poorly understood. Here, we describe a potentially novel in vitro model of exhaustion that uses plate-bound agonists of the NK cell activating receptors NKp46 and NKG2D to induce canonical exhaustion phenotypes. In this model, prolonged activation resulted in downregulation of activating receptors, upregulation of checkpoint markers, decreased cytokine production and cytotoxicity in vitro, weakened glycolytic capacity, and decreased persistence, function, and tumor control in vivo. Furthermore, we discovered a beneficial effect of NK cell inhibitory receptor signaling during exhaustion. By simultaneously engaging the inhibitory receptor NKG2A during activation in our model, cytokine production and cytotoxicity defects were mitigated, suggesting that balancing positive and negative signals integrated by effector NK cells can be beneficial for antitumor immunity. Together, these data uncover some of the mechanisms underlying NK cell exhaustion in humans and establish our in vitro model as a valuable tool for studying the processes regulating exhaustion.
Jacob A. Myers, Dawn Schirm, Laura Bendzick, Rachel Hopps, Carly Selleck, Peter Hinderlie, Martin Felices, Jeffrey S. Miller
This file is in Adobe Acrobat (PDF) format. If you have not installed and configured the Adobe Acrobat Reader on your system.
PDFs are designed to be printed out and read, but if you prefer to read them online, you may find it easier if you increase the view size to 125%.
Many versions of the free Acrobat Reader do not allow Save. You must instead save the PDF from the JCI Online page you downloaded it from. PC users: Right-click on the Download link and choose the option that says something like "Save Link As...". Mac users should hold the mouse button down on the link to get these same options.