Quantitative Studies on the Growth of Herpes Virus in HeLa Cells

Abstract

Less than a tenth of the pock-forming particles of the HFEM strain of herpes virus are able to initiate infection in HeLa cells, even after passage in these cells. The pock-forming virus attaches firmly to the cells but most of it remains susceptible to antiserum and presumably does not penetrate the cell. A small proportion of virus initiates infection in the HeLa cells, and, after exposure to more than one HeLa infectious particle/cell, new virus first appears in the cell fraction 12 hr. after infection, and 4 hr. later virus is released into the medium. Virus in the cell fraction can be detected either by disruption of the cells, or simply by removing the cells from the glass with ethylenediaminetetra-acetic acid (EDTA) or saline. This ‘EDTA fraction’ may contain virus released from the cell surface. An attempt was made to determine the number of virus-yielding cells, by inoculation of whole cells on to the chick chorioallantoic membrane. The proportion which yielded virus was lower than would be expected from the input of HeLa-infectious virus. After removal of superficially attached virus with antiserum, it was not possible to detect infective virus during the latent period in the majority of cells which ultimately released virus.