Therapeutic vaccination against chronic viral infection: the importance of cooperation between CD4+ and CD8+ T cells.

The goal of therapeutic vaccination is to elicit an antiviral immune response within persistently infected individuals and consequently eradicate the infection. CD8+ T cells are potent mediators of viral clearance; however, during chronic infections CD4+ T cell help is required to sustain antiviral CD8+ T cell activity. Therapeutic vaccination should be targeted towards enhancing both CD4+ and CD8+ T cell virus-specific responses.