Ulla Kring Hansen, Candice D Church, Ana Micaela Carnaz Simões, Marcus Svensson Frej, Amalie Kai Bentzen, Siri A Tvingsholm, Jürgen C Becker, Steven P Fling, Nirasha Ramchurren, Suzanne L Topalian, Paul T Nghiem, Sine Reker Hadrup
Merkel cell carcinoma (MCC) is a highly immunogenic skin cancer primarily induced by Merkel cell polyomavirus, which is driven by the expression of the oncogenic T antigens (T-Ags). Blockade of the programmed cell death protein-1 (PD-1) pathway has shown remarkable response rates, but evidence for therapy-associated T-Ag-specific immune response and therapeutic strategies for the nonresponding fraction are both limited. We tracked T-Ag-reactive CD8+ T cells in peripheral blood of 26 MCC patients under anti-PD1 therapy, using DNA-barcoded pMHC multimers, displaying all peptides from the predicted HLA ligandome of the oncoproteins, covering 33 class I haplotypes...
January 30, 2024: Journal of Clinical Investigation