Studies on immunity in poliomyelitis

Summary

The AK strain of poliomyelitis virus was shown to be pathogenic for mice in its 17th monkey passage. The strain was serologically related both to the Lansing type and to the Columbia SK group of viruses. It differed in pathogenicity from the members of the Columbia SK group, except in its high mouse infectivity and haemagglutinating capacity, so that a laboratory contamination with one of these viruses could be excluded. Moreover, the adaptation was frequently repeated under carefully controlled conditions. The mouse-adapted AK strain proved practically avirulent for rhesus and cynomolgus monkeys, but it produced a certain degree of resistance of the central nervous system to the Lansing type and to the Columbia SK group. When rhesus monkeys were fed mouse AK virus, the virus was excreted in the stools, antibodies against the homologous virus developed, and the animals proved resistant to peripheral challenge with the Lansing type, the Columbia SK group and with the Brunhilde type. Peripheral challenge was possible, since it was shown, that paralysis developed in intramuscularly inoculated monkeys with the various types of poliomyelitis virus, and simultaneous injection of cortisone. The origin of the virus and the possibility of its use as immunizing agent in man are discussed.