Replication of respiratory syncytial virus in lungs of immunodeficient mice.

Respiratory syncytial virus was frequently isolated during a 10-day test period from the lungs of 4- to 6-week-old immunodeficient nude (nu/nu) mice and from gamma-irradiated C3H mice inoculated intranasally with this virus, but not from similar aged and comparably inoculated normal littermates of these mice. Virus isolation rates and levels of virus in lungs in both groups of immunodeficient mice were similar. No extrapulmonary dissemination of virus was observed in any test group of mice.