Immunohistochemical analysis of the involvement of F4/80 and Ia-positive macrophages in mouse liver infected with lymphocytic choriomeningitis virus.

The distribution of cells bearing the F4/80 macrophage marker and class II MHC glycoproteins has been analyzed in the livers of mice infected with viscerotropic LCMV. The number of F4/80+ macrophages in the liver increases greatly during infection. Much of this is due to the localization of F4/80+ Ia+ monocytes, large numbers of which attach to the walls of the sinuses and the central and hepatic veins. Numerous lymphocytes are also observed in the sinusoids, frequently in close association with macrophages. The lymphocytes tend to move on from this intravascular location, while the macrophages remain. Foci of F4/80-Ia- mononuclear cells (probably T lymphocytes) are found both in the liver parenchyma and in locations that are obviously perivascular. The most prominent of these lymphocyte cuffs are located in the region of the portal triad. Infiltration of the lymphocyte foci with F4/80+ Ia+ elements occurs late, concurrent with evidence of cell death within the lesion. The dissociation in the focal accumulations of lymphocytes and monocyte/macrophages early in the disease process is both striking and unforeseen.