Further characterization of herpes virus persistence

Area of Science:

• Virology
• Cell Biology
• Molecular Biology

Background:

• Herpes simplex virus type 1 (HSV-1) infection can lead to persistent infections in cell cultures.
• Understanding the cellular factors influencing persistent HSV-1 infection is crucial for viral pathogenesis research.

Purpose of the Study:

• To investigate the conditions supporting the establishment of persistently infected cell cultures with HSV-1.
• To characterize the properties of HSV-1 persistently infected cells and their resistance to superinfection.

Main Methods:

• Infection of cell cultures with HSV-1 under standard conditions.
• Colony formation assays in agarose to assess cell survival and growth.
• Cloning of infected cells and characterization of resulting cell cultures.

Main Results:

• Persistently infected cells capable of growth and colony formation in agarose were obtained.
• The presence of S phase cells (actively synthesizing DNA) at the time of infection correlated with the yield of persistently infected cells.
• High multiplicities of HSV-1 (greater than 10) reduced the yield of persistently infected cells capable of colonial growth.
• Cloned cell cultures exhibited characteristics of persistent HSV-1 infection and resistance to superinfection.
• A rare event during secondary cloning yielded cultures that did not immediately release infectious virus but showed increased resistance to superinfection, eventually reverting to persistent infection.

Conclusions:

• HSV-1 infection can establish persistent cell cultures, with S phase cells playing a key role in survival.
• Persistently infected cell clones demonstrate resistance to superinfection and can revert to a state of active virus release.
• This study provides insights into the mechanisms of persistent viral infections and cellular resistance.