Enterotropic mouse hepatitis virus

Abstract

SummaryMouse hepatitis virus (MHVI, the coronavirus of the mouse, is the most common viral pathogen in contemporary laboratory mouse colonies throughout the world. It is highly contagious with variable clinical manifestations. The majority of infections are subclinical, but can still significantly influence biological responses, thus interfering with research, mainly in the field of immunology. MHV has been intensively studied from a number of research perspectives and has become the prototype for studying the molecular biology of coronaviruses. MHV contains a single-stranded} positive-sense RNA genome ranging from 27 to 31 kb}which is divided into seven genes. Virions consist of four to five structural proteins. There are many MHV strains that vary in virulence, organotropism and cell tropism} and are constantly evolving by naturally occurring mutation and recombination. Based on pathogenesis studies MHV strains are usually grouped according to their primary tissue tropism into two biotypes: polytropic and enterotropic. Enterotropic strains of MHV replicate in the intestinal mucosa and only rarely spread to other tissues. No morphological structure of the virion has as yet been identified that is responsible for enterotropism. The course of an MHV infection is dependent on the virus strain and host factors. Generally, MHV causes an acute, self-limiting infection which is inapparent in adult mice. Neonates are highly susceptible to disease and show high mortality. In an enzootically infected colony, however, they are protected by maternally derived passive immunity. Detection of MHV infections depends on serological screening of colonies. MHV is controlled by culling and rederivation of the affected colony using hysterectomy or embryo transfer or by elimination through cessation of breeding.

Tissue-Specific Abundance of Regulatory T Cells Correlates with CD8+ T Cell Dysfunction and Chronic Retrovirus Loads

“…For example, allogeneic liver grafts can sometimes be maintained without immunosuppressive drugs (34, 35) and systemic tolerance to allogeneic cells can be induced by injection of the cells into the portal vein (36). However, the liver is also quite capable of sustaining effector T cell responses, such as during human infections with hepatitis A virus (37) and mouse infections with mouse hepatitis virus (38). Thus the liver is not purely tolerogenic and can adapt responses according to homeostatic signals (39).…”

Microbiological Quality Assessment of Laboratory Mice in Korea and Recommendations for Quality Improvement

“…Ten ICR mice purchased from each company were euthanized by carbon dioxide overexposure after blood collection under balanced anesthesia using ketamine and xylazine. Samples of blood, liver, kidney, spleen, lung, and colon feces were (Table 3) [5,11,19]. All animal experiments were performed under protocols approved by the Institutional Animal Care and Use Committee of Seoul National University.…”

The Widespread Evolutionary Significance of Viruses

“…I propose that these stable evolutionary states of viral persistence are due to a strategy we can call virus addiction ( Villarreal, 2005 ) and that MHV can provide the exemplar of such a state. The CNS demyelinated disease that MHV can induce is most observed in newborn pups ( Homberger, 1997 ;Nash et al , 2001 ) and once in the brain, MHV can persist in CNS with recurring disease ( Marten et al , 2001 ). In wild asymptomatic mice, MHV is found mostly as an enteric infection.…”