Profound protection against respiratory challenge with a lethal H7N7 influenza A virus by increasing the magnitude of CD8 T-cell memory

Abstract

The recall of CD8+ T-cell memory established by infecting H-2b mice with an H1N1 influenza A virus provided a measure of protection against an extremely virulent H7N7 virus. The numbers of CD8+ effector and memory T cells specific for the shared, immunodominant DbNP366 epitope were greatly increased subsequent to the H7N7 challenge, and though lung titers remained as high as those in naive controls for 5 days or more, the virus was cleared more rapidly. Expanding the CD8+ memory T-cell pool (10%) by sequential priming with two different influenza A viruses (H3N2→H1N1) gave much better protection. Though the H7N7 virus initially grew to equivalent titers in the lungs of naive and double-prime..