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Aging and reactivation of latent murine cytomegalovirus
K E Schmader1, R Rahija, K R Porter
1Department of Medicine, Duke University Medical Center, Durham, North Carolina 22710.
Abstract:
BALB/c mice were experimentally infected with murine cytomegalovirus (MCMV) to discover whether latent MCMV persisted in aging mice and to examine the effect of aging on MCMV reactivation. Latently infected mice received saline, cyclophosphamide, or allogeneic blood at 6 and 18 months of age. MCMV DNA was detected by polymerase chain reaction in submaxillary salivary gland biopsy specimens from saline-treated young and old mice. Evidence of MCMV reactivation was sought by culture of biopsy specimens and by MCMV IgG ELISA of pre- and posttreatment sera from all animals. Very few cyclophosphamide- or saline-treated mice reactivated MCMV at either age, but young transfused mice reactivated MCMV significantly more often than did old transfused mice. These experiments indicate that MCMV DNA persists in the salivary gland of aging mice but that the likelihood of MCMV reactivation does not increase with age.
Insights
Aging mice harbor persistent murine cytomegalovirus (MCMV) DNA in salivary glands. However, aging does not increase the risk of MCMV reactivation, challenging previous assumptions about viral persistence and immune aging.
Area of Science:
- Virology
- Immunology
- Gerontology
Background:
- Murine cytomegalovirus (MCMV) establishes lifelong latent infections.
- Aging is often associated with altered immune responses and increased susceptibility to infections.
Purpose of the Study:
- To investigate the persistence of latent MCMV in aging BALB/c mice.
- To determine the impact of aging on MCMV reactivation following experimental challenge.
Main Methods:
- BALB/c mice were infected with MCMV and treated with saline, cyclophosphamide, or allogeneic blood at young and old ages.
- MCMV DNA detection via polymerase chain reaction in salivary gland biopsy specimens.
- MCMV reactivation assessed by viral culture and MCMV IgG ELISA.
Main Results:
- MCMV DNA was consistently detected in the salivary glands of both young and old latently infected mice.
- MCMV reactivation was infrequent in saline- or cyclophosphamide-treated mice.
- Young mice receiving allogeneic blood showed significantly higher MCMV reactivation rates than old mice.
Conclusions:
- Latent MCMV DNA persists in the salivary glands of aging mice.
- Aging does not enhance the likelihood of MCMV reactivation.
- Allogeneic blood transfusion may trigger MCMV reactivation, with a higher incidence in younger mice.