Nuanced View on PD-1 as an Exhaustion Marker

The marker PD-1 is not definitive in determining T cell exhaustion as it can also be expressed in non-exhaustive conditions. Studies reveal that the expression of PD-1 does not solely indicate T cell exhaustion; hence, researchers explore measuring other functions of T cells. Research by Arlene Sharp indicates that PD-1 is rapidly downregulated on activated T cells, challenging its classification as an exhaustion marker. This underscores the need to understand various exhaustion markers beyond PD-1 for a comprehensive insight into T cell exhaustion.