Sensitivity of FL cells to polio- and adenoviruses

Summary Poliovirus plaque counts on the FL strain of human amnion cells were almost double the counts on rhesus monkey kidney for the same virus preparation, repeatedly assayed over more than six months. FL cells gave more consistent results in virus assay than monkey kidney cells. Plaque counts obtained with FL cells were 2 1/2 to 5 times higher than those obtained with HeLa, Chang's conjunctiva and Detroit-6 cells.Using the chick embryo-adapted MEF-1 strain of poliovirus, FL cells and primary human amnion cells reacted similarly in respect to plaque count and morphology, while no distinct plaques were seen on monkey kidney or HeLa monolayers under comparable conditions. For infectivity assays of adenovirus suspensions based on cytopathogenic effect, FL cells were found suitable, although no plaque formation was obtained.Aided by American Cancer Society Grant E-82 and a grant from the National Foundation.