MKI67 and infection: Interestingly, the percentage of Ki67 + NK cells rapidly declined in LVL animals and reached pre-infection levels at 8–12 weeks p.i. with a mean value of 9.7% (95% CI [8.7, 10.8]), whereas in contrast a significantly higher amount of proliferating NK cells was observed in HVL animals as long as 8–12 weeks p.i. (t-test, p < 0.0001) with a mean value of 46.4% (95% CI [42.3, 50.4]) Ki67+ NK cells that was sustained significantly (p < 0.0001) at high levels during the chronic phase of infection.