The Multiplication of Measles Virus in Human Amnion Cells in vitro

Laboratory of Microbiology, State University, Catharijnesingel 59, Utrecht, The Netherlands The multiplication of the EDMONSTON strain of measles virus in suspensions of human amnion cells was studied. The first new virus appeared in the cytoplasmic fraction of the cells 17 to 20 hr after infection. After another 7 hr the virus was liberated into the medium. The multiplication of the virus was not inhibited by actinomycin D as measured by virus growth, virus plaque formation, or change in sensitivity to u.v.-irradiation. The u.v.-irradiation of monolayers before infection did not reduce plaque formation. Received 25 June 1969; accepted 13 November 1969.