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

Abstract

"M.M." virus and Russian Spring-summer encephalitis were tested by injecting serial dilutions by the intraperit. route in animals previously given a series of subcut. inoculations of trypan red. Trypan red under these circumstances in several series of tests, using over 500 mice, did not manifest any significant protection against either virus. The apparent protective effect obtained in previous expts. by Wood and Rusoff, who gave both agents intraperit., is interpreted as being due to a non-specific peritoneal protection afforded by certain inert substances when injected previous to the inoculation of infectious agents by the same route. The results of the present expts. suggest that these two neurotropic viruses do not enter the central nervous system directly by way of the vascular channels as in the case with such an agent as cocaine, the passage of which, into the central nervous system tissue, may be altered by trypan red.