353 Interaction of Mouse Peritoneal Macrophages with Different Arboviruses in vitro

In vitro cultured mouse peritoneal macrophages are inefficient host cells for both alpha and flaviruses tested. Production of infectious virus ceased 6 to 24 h after infection, except for virulent and avirulent SF strains. This limited growth is unrelated to interferon production. No correlation was found between the LDs0 of different virus strains for mice and the virus yields of in vitro infected macro-phages therefrom. When macrophages from SF immunized mice were inoculated in vitro with SF or EEE, a cytopathic effect occurred, while the multiplication ofSF, but not of EEE, was decreased. Virus multiplication i proteose peptone induced macrophages was enhanced for SF strains only. These results are discussed in relation to the virulence of several arboviruses for mice