FIG. 4.

Plaque assays of virus titers in selected organs and tissues of IFN α/β/γ R^−/− and IFN α/β R^−/− mice harvested 2 or 3 days after footpad infection with 2 × 10⁶ KOS/dlux/oriL. Data are presented as mean values ± standard error of the mean. The dashed line shows the limit of detection (30 PFU/ml/g of tissue) for spleen, lung, kidney, and brain. The solid line denotes the limit of detection (10 PFU/ml/g of tissue) for the spine. The sensitivity for detection of virus in the liver was 500 PFU/ml/g of tissue. There were four IFN α/β/γ R^−/− mice on day 3, and two mice each for IFN α/β/γ R^−/− on day 2 and for IFN α/β R^−/− on day 3 postinfection.