Characterization of IFN-α/β–mediated leukocyte trafficking to livers. Bone marrow leukocytes were harvested from uninfected 129-IFN-α/βR⁺ and 129-IFN-α/βR^– mice and fluorescently labeled as described in Methods. Cells were transferred intravenously to C57BL/6-MIP-1α^– recipient mice that were uninfected or infected with MCMV for 24 hours. Livers were harvested 24 hours after cell transfer, processed, sectioned, and examined by fluorescence microscopy. Sections shown are from an uninfected MIP-1α^– recipient after transfer of cells from uninfected IFN-α/βR⁺ donor mice (a and d); an MIP-1α^– recipient infected with MCMV for 48 hours, after transfer of cells from uninfected IFN-α/βR⁺ donor mice (b and e); and an MIP-1α^– recipient infected with MCMV for 48 hours, after transfer of cells from IFN-α/βR^– mice (c and f). Images were digitally captured at the original magnifications of ×10 (a–c) and ×20 (d–f). Scale bars = 100 μm.