For many viral infections, resolution of illness is associated with long-term host control of viremia rather than viral eradication. An example is EBV infection, and the fact that host immune suppression is associated with EBV-induced disease suggests that it is the immune system that is holding the virus in check (1, 2). Other viruses are typically associated with progressive uncontrolled disease, and represent an expanding global problem. Over 30 million persons are estimated to be infected with HIV-1 (3), and HCV infection involves 4–6% of the population in certain geographic regions of the world (4). Understanding the correlates of immune protection against such progressive viral infections and the development of effective vaccines thus has great urgency.
Data from both human studies and murine models suggest that CTLs are an important host defense against viruses. CTLs recognize viral peptides that are processed intracellularly...
