Production of Fever by Influenzal Viruses. IV. Tolerance to Mumps and Influenza Pyrogens

Abstract

The fever-producing capacities of mumps and the PR8 strain of influenza viruses were studied in animals pretreated with the heterologous strain. Intraven. injn. of mumps virus causes a febrile response in rabbits similar to that produced by influenza or Newcastle disease viruses. Animals are partially or completely resistant to a 2d injection of mumps virus 24 hrs. later. Pretreatment with the PR8 strain in influenza A virus also inhibits the febrile response to mumps virus. Mumps virus itself is equally effective in producing tolerance to the PR8 strain.