Cultivation of Measles Virus in Human Amnion Cells and in Developing Chick Embryo.

Summary 1. A strain of measles virus originally isolated in cultures of human renal cells has been propagated throughout 28 serial passages in cultures of human amnion cells. In the latter system it induces 2 types of cytopathic change: (1) formation of “syncytia” or “multinuclear giant cells” in which intranuclear and intracytoplasmic inclusions are prominent features; (2) only recently recognized, the assumption by individual epithelial cells of a characteristic fusiform or stellate configuration. In certain of these affected cells eosinophilic intranuclear inclusions are present that resemble those found in the nuclei of the syncytia. Eventually both types of change terminate in cellular necrosis and disintegration. In contrast to the dual response of amnion cells only the formation of syncytia has been observed in cultures of renal cells infected with the virus. 2. The Edmonston strain of measles virus from the 28th passage in human amnion cells was inoculated into chick embryos. In this host it has been maintained throughout 12 successive passages. Multiplication of the agent was demonstrated by addition of chick embryonic materials to cultures of human amnion cells. This procedure was necessary since no definite indication of viral activity has as yet been distinguished within the egg. 3. The virus present in the 9th chick embryo passage was identified as the measles agent in complement fixation and virus-neutralization tests with acute and convalescent phase measles sera.