Herpes simplex virus type 1 long-term persistence, latency, and reactivation in infected Burkitt lymphoma cells

Persistent infection of a lymphoma cell line by herpes simplex virus

The peripheral blood cells from a patient with a B-cell lymphoma were established in long-term tissue culture. Two years after establishment of the cells in culture they were infected with herpes simplex virus type 2 and the productivity and duration of viral persistence investigated. One week after infection the lymphoblastoid cells were productively infected and have remained so for a period of over 3 years. Expression of a viral glycoprotein antigen was evaluated by using a fluorescein-labeled monoclonal anti-herpes simplex virus type 2 antibody and revealed a spectrum of staining reactions grading from a lightly stippled to very intense pattern. Polymerase chain reaction analysis of the infected cells revealed the presence of the herpes simplex virus type 2 DNA polymerase gene in the infected cells that was absent from the uninfected lymphoblastoid cells. These results taken together with the long-term growth characteristics of both the infected and uninfected lymphoblastoid cells suggest that this cell line may be a good model system for studying viral infection, viral replication, viral latency, and clinical application for the isolation of human herpes virus.

HSV type 1 genome variants from persistently productive infections in Raji and BJAB cell lines

We studied possible genomic changes occurring in herpes simplex virus type 1 (HSV-1) during long-term cell culture which served as a model system for persistence and latency studies as introduced earlier. Sixteen HSV-1 reisolates were isolated from persistently productive HSV-1 (strains F and AK)-infected Burkitt lymphoma cell lines Raji and BJAB at four different times. They were roughly characterized in plaque morphology, plaque size, and infectivity. The viral reisolate DNAs revealed deletions and insertions of up to 1,150 base pairs in fragments BamHI-B, -E, -F, -J, -V, -X, and in the L-terminal and junction fragments S and K. Results were confirmed by additional restriction enzyme analyses and DNA sequencing of selected genomic regions between map units 0.642-0.650, 0.763-0.778 and 0.887-0.934. There was a progressive increase in genomic variability over a three-year period. However, changes in DNA fragment size occurred at different rates, with some reisolates showing stability over several months. The selective pressure for HSV-1 (F and AK) genomic changes was stronger in Raji than in BJAB cells, and stronger for F than for AK strain.

The role of the immune system in establishment of herpes simplex virus latency--studies using CD4+ T-cell depleted mice

The immunological mechanisms involved in establishment of herpes simplex virus (HSV) latency were studied in normal and CD4+ T-cell depleted C57BL/6J mice following intravaginal infection. During transition from acute to latent ganglionic infection two consecutive processes were observed: first, clearance of infectious virus from the ganglia, and second, reduction of the number of infected ganglia.