FIG 1.
Timing of NK cell immunoregulatory activities during pathogenic medium-dose infection. C57BL/6 mice (n = 3/group) were treated with either NK cell-depleting anti-NK1.1 antibody or a nondepleting isotype control at various time points relative to i.v. inoculation with a medium dose (2 × 105 PFU) of LCMV clone 13. (A) At day 15 p.i., viral titers in the spleen were determined. Values below the lower limit of detection (log10 PFU = 1.0; dotted line) were assigned a “less than” value. *, P ≤ 0.05 versus nondepleted group. (B) Numbers of splenic IFN-γ+ TNF+ LCMV NP396–404-specific CD8 T cells were determined at day 15 p.i. by intracellular cytokine staining. *, P ≤ 0.05 versus nondepleted group. TNF, tumor necrosis factor. (C) Body weight was measured daily, and three patterns of weight loss were observed. The mean % of initial body weight was graphed as a function of time for nondepleted mice (black line; n = 3) and for pooled (phenotypically) groups of mice depleted at very early (day −1 [D−1], D+1, or D+2) (red line; n = 8) and later (D+3, D+4, or D+5) (blue line; n = 9) times of infection. **, P ≤ 0.01 versus nondepleted group; #, P ≤ 0.05 versus D+3 to D+5 group; ##, P ≤ 0.01 versus D+3 to D+5 group. Data are presented as means ± SEM and are representative of two independent experiments.