Tissue-specific differences in PD-1 and PD-L1 expression during chronic viral infection: implications for CD8 T-cell exhaustion

SD Blackburn, A Crawford, H Shin, A Polley… - Journal of …, 2010 - Am Soc Microbiol
SD Blackburn, A Crawford, H Shin, A Polley, GJ Freeman, EJ Wherry
Journal of virology, 2010Am Soc Microbiol
ABSTRACT The PD-1/PD-L pathway plays a major role in regulating T-cell exhaustion
during chronic viral infections in animal models, as well as in humans, and blockade of this
pathway can revive exhausted CD8+ T cells. We examined the expression of PD-1 and its
ligands, PD-L1 and PD-L2, in multiple tissues during the course of chronic viral infection and
determined how the amount of PD-1 expressed, as well as the anatomical location,
influenced the function of exhausted CD8 T cells. The amount of PD-1 on exhausted CD8 T …
Abstract
The PD-1/PD-L pathway plays a major role in regulating T-cell exhaustion during chronic viral infections in animal models, as well as in humans, and blockade of this pathway can revive exhausted CD8+ T cells. We examined the expression of PD-1 and its ligands, PD-L1 and PD-L2, in multiple tissues during the course of chronic viral infection and determined how the amount of PD-1 expressed, as well as the anatomical location, influenced the function of exhausted CD8 T cells. The amount of PD-1 on exhausted CD8 T cells from different anatomical locations did not always correlate with infectious virus but did reflect viral antigen in some tissues. Moreover, lower expression of PD-L1 in some locations, such as the bone marrow, favored the survival of PD-1Hi exhausted CD8 T cells, suggesting that some anatomical sites might provide a survival niche for subpopulations of exhausted CD8 T cells. Tissue-specific differences in the function of exhausted CD8 T cells were also observed. However, while cytokine production did not strictly correlate with the amount of PD-1 expressed by exhausted CD8 T cells from different tissues, the ability to degranulate and kill were tightly linked to PD-1 expression regardless of the anatomical location. These observations have implications for human chronic infections and for therapeutic interventions based on blockade of the PD-1 pathway.
American Society for Microbiology