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Theiler's murine encephalomyelitis virus--characterization of newly isolated viruses from Japanese mouse colonies
1Laboratory Animal Center for Biomedical Research, Nagasaki University School of Medicine, Japan.
Abstract:
The hemagglutinating-inhibition (HI) test was used to detect antibodies for Theiler's murine encephalomyelitis virus (TMEV), and the virus was isolated from sero-positive mice derived from colonies in Japan. HI antibody was detected in conventional mice (38.7%; 137/354) at titers ranging from 1:8 to 1:512, but it not in SPF mice (0/90). To isolate the virus, weanling mice inoculated intracerebrally with samples obtained from sero-positive mice were sacrificed and 10% brain homogenates were subcultured. New isolates designated as YOC and AB strains were obtained, and their physicochemical and biological properties were characterized. The results indicated that the new isolates were similar to Theiler's original (TO) strain according to the following observations of persistent paralysis of the hind limbs, resistance to ether treatment, a particles size of 10 approximately 50 nm in diameter, stability at pH 3, a density of 1.35 g/cm3 and three major and one minor viral proteins, (VPO; 38 Kd, VP 1; 33 Kd, VP2; 32Kd, VP3; 25 Kd). Immunoblotting analysis also showed that VP 2 of YOC and encephalomyocarditis virus of the Cardiovirus group, reacted strongly with the antisera against the viruses as well as with the GDVII strain. These results suggest that TMEV infection does exist in conventional mouse colonies in Japan, and that these viruses resemble the TO strain of TMEV.
Insights
Theiler
Area of Science:
- Virology
- Immunology
- Neuroscience
Background:
- Theiler's murine encephalomyelitis virus (TMEV) is a significant pathogen in mouse models.
- Understanding TMEV prevalence and characteristics is crucial for research.
- Previous studies have not fully characterized TMEV strains in Japanese mouse colonies.
Purpose of the Study:
- To detect TMEV antibodies and isolate the virus from conventional mouse colonies in Japan.
- To characterize the physicochemical and biological properties of new TMEV isolates.
- To compare the new isolates with the Theiler's original (TO) strain.
Main Methods:
- Hemagglutinating-inhibition (HI) test for antibody detection.
- Virus isolation from sero-positive mice via intracerebral inoculation.
- Characterization of viral properties including ether resistance, particle size, pH stability, density, and protein composition.
- Immunoblotting analysis for viral protein characterization.
Main Results:
- HI antibodies for TMEV were detected in 38.7% of conventional mice but not in SPF mice.
- Two new TMEV isolates, YOC and AB strains, were obtained from Japanese mouse colonies.
- The new isolates exhibited properties similar to the TO strain, including causing hind limb paralysis and sharing viral protein profiles.
Conclusions:
- TMEV infection is present in conventional mouse colonies in Japan.
- The isolated YOC and AB strains are similar to the TO strain of TMEV.
- These findings highlight the importance of monitoring TMEV in research animal populations.