Vaccination with Egg Passage Measles Virus by Inhalation

Introduction  By using the interference method with mumps virus, it has been shown that measles virus could be serially cultivated in the chorioallantoic and amniotic cavities of developing chick embryos. As difficulties were, however, encountered in measuring the virusThe long-term amniotic-passaged Toyoshima strain was employed in vaccination experiments in monkeys³ and children.^3,4

Result  Measles virus of the Toyoshima strain can be serially cultivated in the amniotic cavity dose by this method, the Toyoshima^1,2 strain, isolated in our laboratory and passaged serially in the amniotic cavity, was quantitatively determined by introduction into FL cells. of developing chick embryos without decrease of virus titer in FL cells, titers of approximately 10⁴ per milliliter TCID₅₀ being constantly obtained in spot titrations.The presumption that this long-term eggpassaged Toyoshima strain measles virus might be attenuated was substantiated in vaccination experiment of monkeys, in which good antibody responses were