An Effective Method of Intraneural Inoculation of Poliomyelitis Virus. ∗

Abstract

The uncertainty of results obtained by most investigators with intraneural injections of poliomyelitis virus has limited the use of this method of inoculation for inducing experimental poliomyelitis. Neveretheless, if the virus of poliomyelitis is truly neurotropic, one would expect that intraneural inoculation would be as effective as intracerebral inoculation, and simpler, if the virus could actually be made to come into contact with numerous nerve fibers, rather than being forced along and between connective tissue sheaths within the peripheral nerve. This of course is strongly suggested by the work of Fairbrother and Hurst, 1 who showed that trauma during intraneural injection facilitates “takes” by this method of inoculation.

Going one step farther, and with the knowledge that during the first few days after nerve section the nerve cells with axons cut are more susceptible to the virus than normal cells, 2 it was decided to determine whether simple section of a peripheral nerve and immersion of the central stump in virus suspension for a few minutes was sufficient to produce poliomyelitis. This method, which involves no mechanical injection pressure, and which places the virus in contact with the protoplasm of every axon in the nerve, was found to be highly successful in producing poliomyelitis. When a large nerve, such as the sciatic nerve, was used, this method of inoculation was invariably successful with two strains of known potency, the MV and Wfd 3 strains.

In 9 Rhesus monkeys the sciatic nerve was sectioned with sharp scissors peripheral to the sciatic notch or at the mid-thigh level, and the central cut end then soaked in as little as 0.1 cc of 20% virus suspension for several minutes. Poliomyelitis resulted after an incubation period of 4-6 days.