Mouse Hepatitis Virus Type Research Articles

Bone-marrow derived macrophages as targets for the replication of mouse hepatitis virus type 3

Bone-marrow (BM) derived macrophages are sensitive target cells for replication of mouse hepatitis virus type 3 (MHV3). These cells can be grown in large numbers and the percentage of defined macrophages increased until day 10 when 100% of the cells represented macrophages. MHV3 replicated within these cells to high titers and caused the formation of multi-nucleated giant cells. This effect was seen with very low virus inocula in BM macrophages of C57BL/6 mice that are highly susceptible to in vivo infection with MHV3 whereas macrophages from resistant A/J mice did not show a cytopathic effect at these virus doses. 1000-fold higher virus doses, however, caused the cytopathic effect in macrophages of both C57BL/6 and A/J mice.

Activation of Natural Killer Cells and Induction of Interferon After Injection of Mouse Hepatitis Virus Type 3 in Mice

Activation of Natural Killer Cells and Induction of Interferon After Injection of Mouse Hepatitis Virus Type 3 in Mice

Adult mouse hepatocytes in primary monolayer culture express genetic resistance to mouse hepatitis virus type 3.

Adult mouse hepatocytes in primary monolayer culture express genetic resistance to mouse hepatitis virus type 3.

Virus persistence and recurring demyelination produced by a temperature-sensitive mutant of MHV-4.

Mouse hepatitis virus type 4 (MHV-4, the JHM strain), a positive-strand RNA virus of the coronavirus family, is well documented as an inducer of acute1–4 and chronic5,6 demyelination in mice, as well as subacute demyelination in rats7,8, due to a cytolytic infection of oligodendrocytes3,4,7. However, experiments to explore the role of virus and host factors in the production of chronic or recurrent demyelinating disease have been limited because MHV-4 usually produces demyelination in conditions that frequently induce a fatal necrotizing encephalomyelitis1–9. To circumvent this problem, we had made and selected mutant viruses that caused both a high incidence of demyelination and a low incidence of encephalitis-induced mortality9. One such mutant, designated ts8, consistently caused acute demyelinating disease in over 90% of intracerebrally or intranasally (natural route of infection) inoculated, 4–5 week-old mice from several susceptible strains within 6–10 days9,10. In addition, ts8 typically did not cause fatal necrotizing encephalitis, showing a low mortality (<5%)9,10. This reflected a unique tropism of ts8 for oligodendrocytes, but a limited one for neuronal cells11. We now report that ts8 is also useful for inducing persistent infection of the mouse central nervous system (CNS). The histopathological correlate of this infection is chronic recurrent demyelination, and virus can be demonstrated ultrastructurally in intact oligodendrocytes, in the vicinity of demyelinated areas.

Immunopathology of mouse hepatitis virus type 3 infection: IV. MHV 3-induced immunodepression

Humoral immunity was studied in mice during the development of MHV 3-induced persistent infection. Sequential determinations of immunoglobulins showed a progressive decrease of all Ig levels during the first 3 months of infection, followed by a return to normal levels. When tested 40 and 80 days after infection, primary and secondary PFC responses and serum antibody titers against SRBC and LPS were markedly diminished, in paralyzed as well as in nonparalyzed mice. Conversely, anti-MHV 3 antibody titers reached maximal levels by Day 90, slowly decreasing thereafter. MHV 3 was recovered from brain and liver and from peritoneal macrophages during the first 3 months of infection only. MHV 3-induced immunodeficiency observed during the chronic phase of the disease seems to be related to virus-induced lympholysis and inhibition of lymphocyte proliferation.

Mouse hepatitis virus type 4 (JHM strains). induced fatal central nervous system disease. I. genetic control and murine neuron as the susceptible site of disease.

Mouse hepatitis virus (JHM strain) type 4 induces acute encephalitis followed by death in many strains of laboratory mice. Immunohistochemical study in vivo and analysis of mouse neuronal cells in vitro both indicate that the target cells in this infection is the neuron. Further, examination of several inbred mouse strains and neuronal cells from them shows that disease expression is controlled by a single autosomal gene action at the level of the neuronal cell. Susceptibility is dominant but not H-2 linked. However, cultured neuronal cells and macrophages from SJL/J mice, which are resistant to this infection, fail to make significant amounts of infectious virus after an appropriate viral inoculation. Apparently the defect is not at the level of the virus-cell receptor, because these cells, in part, express viral antigens.

Role of macrophages and interferon in natural resistance to mouse hepatitis virus infection.

Among the many models of experimental viral infections, the mouse hepatitis virus (MHV) model offers a number of advantages for investigation of the host-virus relationship: 1. MHV infection is a naturally occurring infection in the mouse (Rowe et al. 1963); Broderson et al. 1976; Ishida et al. 1978) and thus is not an artificial model. 2. In the case of mouse hepatitis virus type 3 (MHV-3), the natural resistance is observed to various degrees according to the mouse strain considered (Virelizier and Allison 1976), with either full susceptibility, full resistance, or semiresistance being present This provides the opportunity to make correlations with parameters of the immune response in a more precise manner than in other models where only two situations (susceptibility and resistance) are observed. 3. The mouse strains showing variable degrees of susceptibility to MHV-3 (namely, A/J, C3H/He, and C57/BL-6) are well-known inbred strains whose biologic parameters have been thoroughly investigated. 4. MHV infections have been among the first models in which the role of macrophages in host defense have been investigated after the pioneering studies of F. Bang and his colleagues (Bang and Warwick 1960; Shif and Bang 1970). 5. MHV-3 induces a very easily recognizable cytopathic effect in mouse macrophage cultures by fusing infected macrophages into multinucleated giant cells (Malucci 1965). The appearance of this cytopathic effect closely parallels the intensity of viral replication and thus provides a useful tool for in vitro studies in macrophages from different strains of mice (Virelizier and Allison 1976). 6. MHV-3 infection is so far the only Coronavirus model in which the protective role of interferon in vivo has been demonstrated (Virelizier and Gresser 1978). 7. Finally, the modification of immune responsiveness during acute or persistent infections has been investigated (Virelizier et al. 1976). KeywordsInterferon ProductionMouse Hepatitis VirusImmune InterferonKuppfer CellAntiviral RoleThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Heterogeneity in evolutive patterns of inbred mice infected with a cloned substrain of mouse hepatitis virus type 3.

F1 hybrid mice, resulting from a cross between a susceptible and a resistant parent, were infected with a cloned substrain of mouse hepatitis virus type 3 (MHV3). Results showed various evolutive patterns ranging from fulminant hepatitis to persistent infection and excluded virus variation as an explanation for different disease types. Since host resistance to MHV3 has been previously shown to be under the genetic influence of 1 or 2 genes only rather than a polygenic phenomenon, these results strongly suggest that nongenetic factors play a major role in the determination of evolutive patterns.

Prostaglandins as probable mediators of the suppression of antibody production by mouse hepatitis virus infection

Indomethacin treatment in vivo reversed the suppression of anti-SRBC PM response of A/J mice infected with mouse hepatitis virus type 3. This suggests that prostaglandin production participates in the phenomenon of immunodepression induced by virus infections.

Analysis and localisation of mouse hepatitis virus 3 (MHV3) polypeptides

SummaryThe analysis by SDS-polyacrylamide gel electrophoresis of purified mouse hepatitis virus type 3 revealed the presence of five polypeptides, three of them contained carbohydrate. The molecular weight of these proteins was 190,000 daltons (VGP100), 100,000 (VGP100), 58,000 (VP58), 25,000 (VP25) and 24,000 (VGP24). The analysis of particles obtained after limited proteolysis with bromelain suggests that VGP190 and VGP100 form the spike layer, that VP25 and VGP24 are membrane-associated and that VP58 represents the inner core polypeptide.

Protection and therapy of mice with acute and chronic experimental virus infections with propionibacterium granulosum KP-45

The protection of mice against experimental infections with three different viruses (herpes simplex, vaccinia and mouse hepatitis) by Propionibacterium granulosum strain KP-45 and isolated cell walls was investigated. Pretreatment of NMRI mice with P. granulosum strain KP-45 3-7 days prior to HSV intranasal infection resulted in lowering of mortality rate (herpes encephalitis) from about 95% in controls to 15-30%. Pretreatment of NMRI mice prior to vaccinia virus infection also caused a significant decrease of the number of specific tail lesions. Infection of BALB/c mice with mouse hepatitis virus type 3 (MHV-3) resulted in development of acute infection with lethality in 4-6 days, while in fairly resistant C3H mice chronic infection manifested by loss of weight, uncoordination followed by paralysis and death in few months was observed. Pretreatment of BALB/c mice 3-7 days prior to MHV-3 infection lowered the mortality rate to about 25-30% while no effect was observed in animals injected with P. granulosum KP-45 on the day of virus inoculation. In chronic MHV-3 infections treatment with P. granulosum KP-45 was started 2 weeks after virus inoculation and was continued every 10 days. This resulted in a significant lowering of the number of paralysed mice and in a decrease of the mortality rate. Titre of MHV-3 recovered from livers of infected mice 4 months after virus inoculation was also significantly lower in animals treated with P. granulosum KP-45 or isolated cell walls.

Haemagglutination by mouse hepatitis virus type 3

Partially purified preparations of mouse hepatitis virus type 3 (MHV 3) agglutinated fowl, day-old chick, ferret, hamster and human O erythrocytes at 4, 20 and 37°C and mouse erythrocytes at° C.

Genetic Study of Mouse Sensitivity to MHV3 Infection: Influence of the H-2 Complex

Abstract Genetic study of acute and chronic mouse hepatitis virus type 3 disease was carried out in segregating generations of a cross involving a susceptible (C57BL/6) and a resistant (A/J) mouse strain. The data obtained indicate that one or two recessive genes may be involved in resistance of acute and chronic diseases but suggest that the genes involved in both diseases are different. In this cross, no correlation was observed between H-2 and acute or chronic disease. In mice of congenic lines, however, A/Sn (H-2a), A.SW (H-2a), A.BY (H-2b), and A.CA (H-2f), it appeared that the presence of the H-2f allele conferred to heterozygote as well as to homozygote animals the capacity to resist the development of chronic disease. It seems, therefore, that MHV3 sensitivity in mice is under the influence of at least two major genes: one for the acute disease and the other, H-2 linked, for the chronic disease.

Role of Interferon in the Pathogenesis of Viral Diseases of Mice As Demonstrated by the Use of Anti-Interferon Serum

Abstract Potent sheep anti-mouse interferon globulin has been used to determine the role of virus-induced interferon in mouse hepatitis virus type 3-infected susceptible (C57BL/6), semiresistant (C3H/He), and resistant (A/J) strains of mice. Injection of anti-interferon globulin accelerated the onset of death in C57BL/6 mice, induced almost 100% mortality in C3H/He mice that usually do not die of acute disease, and caused death in 4- and 6-week-old A/J mice, but not in older mice. We conclude that interferon is an important host defense factor in the initial response of different strains of mice to MHV-3 infection. Other factors, however, such as the capacity of macrophages to restrict viral multiplication probably underlie the genetically determined susceptibility or resistance of mice to MHV-3 infection.

In vitro growth characteristics and heterogeneity of mouse hepatitis virus type 3

SummaryThein vitro virus yield of MHV3 reached 107 PFU/ml in mouse DBT cells infected with a virus suspension in HEPES-buffered medium containing DEAE-dextran. The virus titer was 106 PFU/ml in the presence of 10 µg actinomycin D/ml. MHV3 grown in DBT cells gave three peaks of density (1.10–1.14 g/cm3, 1.18–1.20 g/cm3, and 1.25–1.31 g/cm3) in sucrose gradients. All these peaks retained infectivity.

Neonatal Susceptibility to MHV3 Infection in Mice

Abstract Up to 3 weeks of age, mice of the resistant A/J strain are fully susceptible to mouse hepatitis virus type 3 infection (MHV3). Immune deficiency, however, resulting from neonatal thymectomy or long term ALS administration led A/J animals to remain susceptible when tested at adult age. Whole spleen cells transferred from normal adult A/J donor mice protected suckling syngeneic recipients from i.p. infection with MHV3. Such a protective capacity of spleen cells was abolished after treatment with anti-θ serum and complement. Spleen cell separation by means of adherence to plastic also showed that neither the nonadherent nor the adherent populations injected separately were able to confer resistance to young mice challenged with the virus. Protection was not achieved with peritoneal cells originating from adult syngeneic animals. Transfer of resistance to MHV3 was obtained, however, when peritoneal cells were associated with adherent spleen cells. This study indicated that two types of mature cells, at least, were required for transferring MHV3 resistance into newborn mice of the A/J strain: T lymphocytes and an adherent spleen cell population.

An improved method for titration of mouse hepatitis virus type 3 in a mouse cell culture

SummaryPlaque assay in DBT cells with DEAE-dextran and trypsin presents a titration system for MHV3 as sensitive as the LD50 assay in mice.

Immunopathology of Mouse Hepatitis Virus Type 3 Infection

Abstract Humoral and cell-mediated immune responses were studied in resistant and susceptible strains of mice infected with mouse hepatitis virus type III (MHV3). Virus was maintained by regular passages in susceptible DBA/2 mice and assayed in DBA/2 mice by LD50 determination. Normal resistant A strain mice were able to clear the virus from liver, brain, and serum within 7 days after infection. No neutralizing antibody was found. Transfer of serum from immunized A strain mice was not effective in protecting susceptible DBA/2 mice against challenge with virus. In A strain animals resistance to MHV3 developed rapidly during the 3rd week of life. During the period of susceptibility, newborns were protected neither by transplacental passages of anti-MHV3 antibodies nor by injection of “educated” thymus cells. These results suggest that the development of resistance to MHV3 infection in mice cannot be explained solely on the basis of humoral or cell-mediated immunity.

AGE DEPENDENCE OF SENSITIVITY TO MHV3 INFECTION IN RESISTANT MICE

Mechanisms of newborns susceptibility to viral infection was studied in A strain mice infected with mouse hepatitis virus type 3(MHV3). Virus was regularly passaged in susceptible adult DBA/2 mice, prepared by liver homogeneization and titered by LD50 determination. Normal adult A strain mice were always resistant to virus. Young isogenic mice however were highly susceptible and 100% of them died when infected during the first two weeks of age. Resistance to disease developed suddenly during the 3d week of life. Passive transfer of serum from immune A mice failed to protect young animals. When newborns from immunized A strain mothers were injected with MHV3 the mortality was similar to that of control groups. In addition A strain newborns were not protected against virus infection either by injection of isogenic spleen cells or by means of educated thymus cells. However when A strain mice were thymectomized at birth they failed to resist MHV3 infection when tested at adult age. Therefore, along with cell mediated immunity it appears that other mechanism(s), e.g. viral replication in susceptible target cells may play an important role in resistance of mice to MHV3.(Supported by INSERM ATP 5).