PERITONEAL MACROPHAGE ALTERATIONS CAUSED BY NATURALLY-OCCURRING MOUSE HEPATITIS-VIRUS

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  • 1 January 1982
    • journal article
    • research article
    • Vol. 106  (1) , 110-117
Abstract
During routine harvest of murine resident peritoneal cells for macrophage function assays, mice showed a 3- to 4-fold spontaneous increase in number of peritoneal cells within 1 wk of being placed in 1 of their animal rooms. While the mice appeared clinically normal, the collected macrophages had highly convoluted membranes and showed enhanced spontaneous tumor cell killing and increased erythrophagocytosis. Histopathologic findings included mild peritonitis and occasional foci of individual hepatocyte necrosis. Routine murine serologic studies and bacterial cultures of the peritoneal cavity were negative. Immunosuppressed mice placed in this room showed severe hepatic necrosis within 4 days and ultrastructural particles characteristic of coronavirus could be demonstrated in the necrotic foci. Mouse hepatitis virus (MHV) was isolated from these livers. Untreated mice showed positive MHV titers as detected by the enzyme-linked immunoabsorbent assay after 21 days in the room. Thus, MHV can have profound effects on macrophage parameters while causing few clinical signs or histopathologic alterations. The complement fixation assay for MHV as included in routine viral screens appears relatively insensitive for detecting outbreaks of MHV.