1.The Ar-339 strain of Sindbis virus rapidly multiplies in plasma clot cultures of chick embryonic tissue and produces a marked cytopathogenic effect on fibroblast-like outgrowths. Similar changes are induced by the virus in cultures of human adult uterine tissue, and monkey testicle tissue. No cytopathogenic effect was observed in cultures of HeLa cells or in fibroblast-like outgrowths from human embryonic skin-muscle tissue.
2.On occasion fragments of chick embryo heart were observed to continue to rhythmically contract although the surrounding outgrowth of fibroblastic cells showed the typical degeneration.
3.A satisfactory neutralization test for the demonstration of neutralizing antibodies in human sera was developed, using cultures of embryonic chick cells. The results of comparative tests indicate that with Sindbis virus, chick embryonic tissue cultures are more practical for use in serological surveys than are infant mice.