FIG 7

IFN-I and NK cells control PLN infection. (a) C57BL/6 mice were given IFNAR-blocking antibody (αIFN) or NK-depleting antibody (αNK) or left untreated (cont) and then infected i.f. with MHV-GFP (10⁵ PFU). One day later, PLN sections were stained for viral GFP plus NKp46⁺ NK cells (NK), myeloid cells (CD68), or SSM (CD169). Nuclei were stained with DAPI. Open arrows show NKp46⁺ NK cells around the subcapsular sinus. Gray-filled arrows show CD68⁺ and CD169⁺ infected cells. (b) NKp46⁺ NK cells were counted on PLN sections of mice treated as described for panel a. Bars show group means. Circles show mean counts for 3 fields of view per section from 3 sections per mouse. IFNAR-blocking antibody significantly increased NK cell recruitment above controls, whereas NK depletion significantly reduced it. (c) Spleen cells of mice given anti-NK1.1 depleting antibody (PK136) (200 μg/mouse in 2 injections 48 h apart) or not (control) were analyzed 24 h later by flow cytometry for expression of the NK cell marker NKp46. n is the number of cells in the boxed region. (d) PLN of mice treated as described for panel a were IC assayed for recoverable virus 1 day after i.f. MHV-GFP. Crosses show means; other symbols show data for individuals. Both NK cell-depleting antibody and IFNAR-blocking antibody increased titers. IFNAR-blocking antibody had a significantly greater effect. (e) GFP⁺ cells on PLN sections described for panel a were counted for 3 views per section across 3 sections per mouse. Circles show mean counts for individuals. Bars show group means. Both IFNAR-blocking antibody and NK cell-depleting antibody increased GFP⁺ cell numbers. IFNAR-blocking antibody had a significantly greater effect.