Herpesviruses infect us all and cause cancer, blindness, and congenital disability. Developing vaccines requires information from both patients and experimental animals. CD4 T cells seem to suppress directly virus replication, and cells in the nose provide an important way for herpesviruses to get in. We will test whether CD4 T cells can clear nasal infection; what targets they recognize; and how they act. Thus we can establish whether CD4 T cell-directed vaccines might protect against disease.