Fig 7. Duration of protection following passive transfer of activated NK cells.

(A) CAST mice were inoculated with PBS or 3.1 x10⁶ activated NK cells. After 4 h, 7 days or 14 days, the mice were challenged with 550 PFU of VACV expressing FLuc. Virus spread was determined from luminescence as described in Fig 2 and ventral images are shown. (B) For the photon flux plot the control mice treated with PBS were grouped together. (C) For the survival curve the control mice treated with PBS also were grouped together.