Figure 3. NK cell-depleted animals develop increased viral titers and tumor burden after EBV infection.

Viral titers in spleen six weeks after EBV infection in animals with (depl /EBV) and without (non-depl /EBV) NK cell depletion (a, n=24, horizontal bar represents geometric mean, two-tailed Mann Whitney test) and whole blood at various time points p.i. (b, n=21–26 per time point, mean ± s.e.m., **P<0.01, ***P<0.001, two-way analysis of variance (ANOVA) with Bonferroni correction). c, percent body weight loss after EBV infection in animals with and without NK cell depletion at various time points p.i. relative to day 0 (n=15–26 per time point, mean ± s.e.m., ***P<0.001, two-way analysis of variance (ANOVA) with Bonferroni correction). d, incidence of all infiltrative tumors at multiple sites six weeks p.i. in animals with and without NK cell depletion (n=36, Fisher's exact test for actual numbers). All data represent composite data from three to four independent experiments. e, spleen with and without tumor formation from NK cell-depleted or non-depleted animals six weeks p.i., respectively (left picture) and liver from NK cell-depleted animal with multiple tumors (right picture). f–k, tumor morphology. f–h, pleomorphic immunoblasts including occasional Reed-Sternberg like-cells (H&E) (f) and g, pleomorphic immunoblasts showing CD30 expression. h, EBV infected cells with expression of LMP1. Original magnification, 400×. i and j, EBNA1⁺ (brown nuclear staining) pleomorphic immunoblasts in tumor bearing kidney (i, arrow indicates glomerulus and red stars indicate renal tubules) and pancreatic tumor (j, black stars indicate the pancreatic acini). Original magnification, 200×. k, spleen infiltrated by large numbers of granzyme B⁺ cells (original magnification, 400×). All tissue derived from animals six weeks p.i.