AGE-DEPENDENT RESPONSE OF MICE TO A MOUSE HEPATITIS VIRUS, MHV-S

Abstract

ICR mice 4 wk old were fully resistant to mouse hepatitis virus strain MHV-S irrespective of route and dose of inoculation; fatal infection was produced only with cortisone treatment. A 2-wk-old, mice showed high resistance to MHV-S except for intracerebral [i.c.] inoculation, after which 60% of infected mice died. Mice aged .ltoreq. 1 wk, died after i.c., i.p., s.c. and intranasal inoculation, while some survived after peroral inoculation. Between mice aged 4 wk and .ltoreq. 1 wk there was a significant difference in viral growth in the liver after intranasal inoculation; almost the same degree of viral multiplication was seen in the brain of both age groups. Such age-dependent difference in susceptibility to a low-virulent mouse hepatitis virus, especially after nasal inoculation, is discussed in relation to natural infection in mouse breeding colonies.