Preceding reports at this conference have already considered many aspects of the question of markers for the measles virus. Table 1 recapitulates some of these markers that have already been discussed. Two more will have to be added in the light of the report by Dr. Buynak, Dr. Hilleman, and co-workers1 describing the plaques produced by the attenuated Edmonston strain in cultures of chick embryo and grivet kidney cells and the neuropathology produced by the virulent Edmonston strain after thalamic inoculation in the monkey.
Virulent early kidney-cell-passage virus does not seem to grow in chick cells, where
as the attenuated does. In one stable amnion cell line, developed at the Sterling-Winthrop Company laboratories, the 20th passage of the human kidney line induces few or no cytopathic effects. Virus from the 30th passage level in this medium does, however, cause extensive changes. The attenuated agent grows well in this line