Human Cells in Continuous Culture

Human epithelial cells of established and clonal strains in continuous culture, and cynomolgus monkey kidney cells, were studied for comparative susceptibility to Types 1–3 poliovirus, herpes simplex and vaccinia virus. For practical purposes comparative susceptibility was defined as the relative efficiency of cell cultures as instruments for virus assay. This property was evaluated by tube-dilution titers (TCID50) or plaque counts (relative plating efficiencies) obtained with several cell types for a single virus. All cells tested were grown and maintained in yeast-extract medium (YEM) by standardized methods. No titer differences as great as one log were found when: a) two independently prepared pools of each of the five viruses were titrated with parental or clonal strains of HeLa, Maben, conjunctiva, liver, and esophageal epithelium; b) the five viruses were each titrated with four clonal sublines of liver epithelium derived from successive passages of the parental line; c) the five viruses each were passed in liver cells and independently in esophageal epithelial cells to a cumulative log dilution of at least -18, then were titrated with cells of the passage strain, HeLa and monkey kidney cells; or d) all cells were used for assay of Types 1–3 polioviruses by plaque count. Plating efficiency of Maben strains for polioviruses appeared somewhat greater than that of other cells tested. Growth behavior of parental and clonal lines of the newly derived strain of esophageal epithelium resembled that of HeLa cells. The viral spectrum of esophageal epithelial cells included Types 1–3 polioviruses, herpes simplex and vaccinia virus.