Fluctuation of Antiviral Resistance in the Intestinal Tracts of Nude Mice Infected with a Mouse Adenovirus

Abstract

Oral administration of adenovirus strain K87 to BALB/c nude mice resulted in viral proliferation in the intestinal tract up to around week 6 at which point replication was suppressed. In other words, the host acquired resistance. However, this resistance was temporary and the viral infection persisted over a long period with repeated periods of proliferation and resistance. That the appearance of this resistance is the result of infecting mice with the virus and is not due to age difference per se was made clear through experimentation with nude mice of different age groups. However, it was indicated that increase in age is involved in the decreased rate of reproliferation following initial suppression. No evidence of the virus was obtained from any other organ throughout the infection. Furthermore, throughout the persistent infection, even during the aforementioned periods of resistance, no neutralizing antibody was detected from sera, intestinal wall or intestinal content. When spleen cells from BALB/c heterozygous littermate mice was transferred to the nude mice, an earlier onset of antiviral resistance was seen than in nude mice without the transfer, and this was accompanied by a rise in neutralizing antibody titer. From these results, it is believed that the resistance characteristic of nude mice infected by mouse adenovirus is dependent on some factor other than the neutralizing antibody invoked resistance exhibited by euthymic mice.

Natural Pathogens of Laboratory Mice, Rats, and Rabbits and Their Effects on Research

“…MAd-2 may be shed in the feces for 3 weeks in immunocompetent mice (276) and for at least 6 months in athymic mice (669). In contrast to MAd-1, infection with MAd-2 is localized to the intestine, causes no clinical signs, and results in pathologic changes that are limited to intranuclear inclusions in crypt and villous cells of the small intestine (639).…”

Viral Infections of Laboratory Mice

“…MAdV-1 is excreted in the urine and may be shed for up to 2 years [134]. MAdV-2 infects the intestinal tract and is shed in faeces for only a few weeks in immunocompetent mice [135]; immunodeficient mice may shed the virus for longer periods [136].…”