Studies on Growth Characteristics of Human Herpesvirus 7 in vitro

The growth characteristics of Human herpesvirus 7 local strain YY5 were investigated in cord blood mononuclear cells (CBMCs) and CD4 + lymphoblastic cell line SUPT1. Virus growth was demonstrated by cytopathic effect (CPE), percentage of dead cells count, indirect immunofluorescence test with viral antigen expression at different days post infection. At the same time, ultrastructural appearance of infected cells and of HHV 7 in various period were investigated by transmission electron microscopy. The results are as follows: (1) The CPE peak time of HHV 7 was latter than that of HHV 6, and CPE of HHV 7 was less pronounced. (2) Although the CPE was obvious and the viral antigen was found in SUPT1 cells, mature virus particles were hardly observed intra and extra these cells. (3) The virions mainly laid in the giant syncytia. HHV 7 infected cells exhibited heterochromatin clumping and margination or pyknosis, vacuolized cytoplasm, discontinuation of the plasma membrane and necrosis. (4) Mature virus parti