Observations on the Fine Structure and Replication of Varicella Virus in Cultivated Human Amnion Cells

Abstract
Serial propagation of varicella virus in tissue culture was accomplished first by Weller (1953) using human embryonic tissue in roller tubes, and later by Taylor-Robinson (1959) in stationary cultures of human fibroblasts and human amnion cells. However, the virus showed a strange anomaly in these systems in that serial transfer of the agent could not be achieved with culture fluids but only by means of intact infected cells. The virus was thus avidly cell-associated and its infectivity and stability appeared to be entirely dependent on cell integrity and viability (Gold, 1965); cell-disruption by any of a variety of procedures resulted in inactivation of the virus. In marked contrast, the virus in human skin vesicles was found to be mostly extracellular since cell-free filtrates of vesicular fluid sometimes had an infective titre almost as high as the unfiltered fluid (Taylor-Robinson, 1959).