FIG 4.
Effect of NK cell depletion is sensitive to size of LCMV inoculum. C57BL/6 mice (n = 3 or 4/group) were depleted of NK cells or treated with isotype control antibody 1 day prior to infection with a high (2 × 106 PFU) (A) or very high (4 × 106 PFU) (B) dose of LCMV clone 13 i.v. Body weight and survival were monitored for 11 days. (C and D) Mice (n = 5/group) were infected for 10 days with a high (2 × 106 PFU) or very high (4 × 106 PFU) dose of LCMV clone 13 prior to isotype control treatment or administration of anti-NK1.1 antibody. At day 31 p.i., 21 days after treatment, viral titers in the sera (C) and spleens (D) of these mice were determined. (E) For a group of mice infected with the high (2 × 106 PFU) dose of LCMV clone 13, viral titers in sera just prior to depletion of NK cells (day 10) were plotted against the % reduction in viral titers in sera 21 days later (endpoint viral titer/initial viral titer × 100 = % reduction), revealing an inverse relationship between these parameters.