Is a Human CD8 T-Cell Vaccine Possible, and if So, What Would It Take?

Although induction of CD8 + responses is widely accepted as critical in clearing viral infections and necessary for effective vaccines against viruses, much less is known regarding the role of these cells in bacterial and other infections, particularly those that enter the host via the gastrointestinal tract. In this commentary, I discuss the likelihood that CD8 + responses are also important in protection from intestinal Gram-negative bacteria, as well as the many factors that should be taken into consideration during the development of vaccines, based on eliciting long-term protection predominantly mediated by CD8 + responses against these organisms.