Apoptosis induced in mouse hepatitis virus-infected cells by a virus-specific CD8+ cytotoxic T-lymphocyte clone

Morphological changes of mouse hepatitis virus-infected J774.1 cells cocultured with cloned mouse hepatitis virus-specific CD8+ cytotoxic T lymphocytes were examined by electron microscopy. Condensation and margination of chromatin, cellular shrinkage with severe vacuolar degeneration, and blebbing were observed. In addition, fragmentation of cellular DNA was observed, and a decrease in virus titer was accompanied by those changes. These findings show that the cloned cytotoxic T lymphocytes induce in the target cell an internal degradation program termed apoptosis, which results in virus clearance.