Failure of Trypan Red to Protect Against Certain Neurotropic Viruses (“M.M.” and Russian Spring-Summer Encephalitis). ∗

Abstract

Conclusions

Trypan red failed to produce a significant protection against Russian Spring-summer encephalitis virus and “M.M.” virus when the dye was injected subcutaneously and the virus was inoculated by the intraperitoneal route. These experiments fail to confirm the results of others who injected both dye and virus intraperitoneally. We interpret the apparent protective effect obtained by Wood and Rusoff 3 as being due to a well recognized and non-specific peritoneal protection afforded by certain inert substances when injected previous to the inoculation of infectious agents by the same route. Our results suggest that these two neurotropic viruses do not enter the central nervous system directly by way of the vascular channels as is the case with such an agent as cocaine, the passage of which into the central nervous system tissue may be altered by trypan red.