T lymphocytes have a special receptor called CD8 that they use to attach to a cell that has been infected by a virus. Once they recognize the infected cell, T lymphocytes are stimulated to divide and proliferate and they release potent substances known as cytokines with the help of T-helper cells.
An example of a cytokine is gamma interferon.
The cytokines limit viral reproduction while also activating other immune system cells such as macrophages and phagocytes that can destroy an infected cell.