Respiratory diseases in cyclophosphamide-treated mice. II. Decreased virulence of PR8 influenza virus.
Mice infected intranasally with the PR8 strain of influenza virus were treated with cyclophosphamide, a potent immunologic suppressor. During the first week of infection, mortality in the unmodified influenza infection averaged 65%, whereas in those animals also treated with cyclophosphamide it averaged 22.5%. After the first week, the mortality rate in the infected cyclophosphamide-treated animals rose to that seen during the first week in the animals only infected. This decreased mortality in the first week was found despite the fact that the cyclophosphamide-treated and infected animals had higher virus titers which persisted longer, decreased circulating antibody, and a decreased interferon response. This delayed mortality appeared to be related to the finding of decreased cellular infiltration in the lungs of infected cyclophosphamide-treated animals.
D000281:Administration, Intranasal; D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000494:pharmacology*; D007958:Leukocyte Count; D008099:Liver / Q000382:microbiology; D008168:Lung / Q000382:microbiology; D051379:Mice; D009975:Orthomyxoviridae / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity*; D009976:Orthomyxoviridae Infections / Q000150:complications / Q000382:microbiology / Q000401:mortality; D011024:Pneumonia, Viral / Q000209:etiology; D012141:Respiratory Tract Infections / Q000382:microbiology*; D013997:Time Factors; D014774:Virulence / Q000187:drug effects*
D000914:Antibodies, Viral; D003520:Cyclophosphamide