Class I MHC-restricted recognition of cells expressing a gene encoding a 41 amino acid product of the influenza hemagglutinin.

Class I H-2Kd-restricted influenza hemagglutinin (HA)-specific CTL recognize two immuno-dominant sites as represented by synthetic peptides spanning epitopes located in the HA1 and hydrophobic transmembrane domains of the influenza HA. Using a vaccinia virus recombinant expression system, we have examined CTL recognition of HA deletion mutants expressed in target cells. We have demonstrated that a truncated influenza HA gene encoding only the transmembrane anchor region containing a class I recognition site and a short segment of the cytoplasmic tail of the HA can be efficiently presented to class I CTL. These results set the stage for detailed analyses of the intracellular events associated with Ag presentation to class I CTL and offer novel possibilities for future vaccine design.