Replication of herpes-type virus in a Burkitt lymphoma cell line.

Replication of the herpes-type virus in the P3HR-1 Burkitt lymphoma cell line was studied. The cell cultures with 10(6) viable cells/ml were incubated at 33 C for 15 days. The amount of virus in both the cell and fluid portions of the cultures was determined by the loop-drop particle-counting procedure with electron microscopy. An apparent growth curve of the virus was constructed. The maximal cell-associated virus, 10(10) virus particles in an 80-ml culture, was observed after 9 days of incubation. The maximal extracellular virus, 2.5 x 10(9) particles per culture, was observed at the 12th day. About 10% of the released virus particles were enveloped. Under these conditions, there was little or no cell multiplication, but the percentage of immunofluorescent cells reactive to a selected human serum (probably indicating the presence of virus in the cells) increased to a maximum of 50% at the 9th day.