Effects of IFN-α/β functions on MIP-1α production and NK cell accumulation during MCMV infection. Samples were prepared from 129-IFN-α/βR+ (black bars) and 129-IFN-α/βR– (gray bars) mice that were uninfected or infected with 5 × 104 PFU (moderate dose) (a and b) or 1 × 104 PFU (low dose) (c and d) MCMV for 48 hours. Liver leukocytes were harvested and analyzed by flow cytometry as described in Methods. Numbers of DX5+TCR-β– NK cells per g liver are shown (a and c). Data represent the means ± SE (n = 3–6). Liver homogenates were prepared from the IFN-α/βR+ or IFN-α/βR– mice that were uninfected or infected with moderate-dose (b) or low-dose (d) MCMV for 48 hours. MIP-1α protein was measured by ELISA. The levels of detection were 0.06–0.08 ng/g liver. Means ± SE are shown (n = 3–6 mice tested individually). Differences between control IFN-α/βR+ and IFN-α/βR– are significant at *P ≤ 0.03, **P ≤ 0.01, and ***P < 0.0001.