Mouse hepatitis virus strain — Related patterns of tissue tropism in suckling mice

Abstract

The pattern of tissue tropism for several prototype and uncharacterized strains of mouse hepatitis virus (MHV) was studied by intranasal inoculation of each virus strain into groups of neonatal Swiss mice under otherwise identical conditions. Mice were killed at intervals up to 18 days after inoculation, and their tissues were examined for the presence of MHV antigen by indirect immunofluorescence. Two patterns of infection were apparent. Prototype MHV strains 1, 3, A59, JHM, S and uncharacterized MHV strains Tettnang and wt-1 produced a respiratory pattern, in which nose and lung were consistently involved with dissemination to other organs in a vascular distribution. Pulmonary vascular endothelium and alveolar septal cells, but not airway epithelium, were infected. An enteric pattern was observed with MHV-Y and wt-2 in which MHV antigen was largely restricted to the nose and bowel, with limited dissemination to other abdominal organs but not lung. Intestinal lesions in these mice were severe compared to those manifesting the respiratory pattern of infection. These results indicate that, like coronaviruses of other species, different strains of MHV possess different primary and secondary organotropisms following a natural route of inoculation in a susceptible host.

Enterotropic mouse hepatitis virus

“…In susceptible hosts, they spread via viraemia, via lymphatics or along olfactory neural pathways to multiple organs of the body, particularly liver and lymphatic organs. However, while these viruses infect the lymphoid tissues of the intestine, they only minimally infect enterocytes (Barthold & Smith 1984). The terms 'neurotropic' or 'hepatotropic', even though still in use, merely describe which tissue is affected most by strains which have often been experimentally selected for such tropism.…”

“…Neurotropic and hepatotropic isolates were described and emphasized but their affinity to liver or brain were by no means absolute (Barthold & Smith 1984). Pathogenesis studies in mice experimentally infected by a natural route (oronasal inoculationl, however, revealed that these MHV strains all replicated in the upper respiratory tract as a common site of primary replication (Barthold & Smith 1984). In susceptible hosts, they spread via viraemia, via lymphatics or along olfactory neural pathways to multiple organs of the body, particularly liver and lymphatic organs.…”

“…The early classical MHV strains were characterized by the pathology they caused in experimentallyinfected animals, usually following intracerebral or intraperitoneal inoculation. Neurotropic and hepatotropic isolates were described and emphasized but their affinity to liver or brain were by no means absolute (Barthold & Smith 1984). Pathogenesis studies in mice experimentally infected by a natural route (oronasal inoculationl, however, revealed that these MHV strains all replicated in the upper respiratory tract as a common site of primary replication (Barthold & Smith 1984).…”

Replication of Enterotropic and Polytropic Murine Coronaviruses in Cultured Cell Lines of Mouse Origin.

“…To increase our understanding of the virus-cell interactions that occur during MHV infection, the replication of several strains of MHV was compared in various cell lines of murine origin. It has been proposed that MHV is divided into two overlapping biotypes, termed polytropic and enterotropic [2], but the molecular basis for these biotypes is not yet known. In this investigation, we had expected that enterotropic strains would replicate preferentially in the colon carcinoma cell line CMT-93, because this cell line was assumed to provide an environment comparable to that in vivo, but no substantial differences between polytropic and enterotropic strains in viral replication were observed in any of the cell lines tested.…”

The Role of the MHV Receptor and Related Glycoproteins in Murine Hepatitis Virus Infection of Murine Cell Lines

“…MHV-A59 is hepatotropic, and the infection of susceptible mice leads to the destruction of liver parenchymal and Kupffer cells . Howe v er, there is considerable overlap of target tissues bet ween these strains of v i rus (Barthold and Smith, 1984). For example, intracerebral inoculation of MHV-A59 in weanling mice also causes demyelinating disease, although the target cells in this case are non-neuronal cells (Lavi, et al, 1984) .…”