PRF1 and infection: With 1e5 PFU infection, PEP-R619W mature splenic NK cells had reduced degranulation marker CD107a (Fig. S5G and S5H), increased perforin (Fig. S5I and S5J), and an increase in frequency, but not expression, of IFNγ (Fig. S5K and S5L) compared to PEP-WT and PEP-null mature splenic NK cells.