Quantitative Studies on the Neutralization of Equine Encephalomyelitis Virus by Immune Serum

Summary and Conclusions When equine encephalomyelitis virus and a subneutralizing dose of immune serum were mixed and then diluted the titer by intracerebral inoculation was from 10 to 100 times below the titer of the same materials mixed after dilution. When virus was inactivated by mixing with immune serum all dilutions of the mixture were noninfective upon intraperitoneal inoculation. When each was diluted before mixing, animals receiving the higher dilutions were not protected. The filterability of the virus was diminished by mixing with subneutralizing doses of immune serum. It is concluded from these results that the virus and immune body combined in vitro. It is considered probable that aggregation of the virus particles occurred.