Restimulated memory Tc cells have a higher apparent avidity of interaction with targets than primary virus-immune Tc cells as indicated by anti-CD8 blocking.

Previous experiments have shown that whereas a secondary in vitro Kunjin-immune cytotoxic T (Tc) cell population lysed equally well targets infected with either native flavivirus or a recombinant vaccinia virus expressing the immunodominant determinant, primary in vivo Kunjin-immune Tc cells were able to lyse only the recombinant vaccinia virus-infected targets. Using CD8 blockade to assess the avidity of T cell-target interaction, recombinant-infected targets express antigen more efficiently than native flavivirus infected targets and secondary in vitro Kunjin-immune Tc cells have a higher avidity for targets than do primary in vivo Kunjin-immune Tc cells. Secondary in vivo influenza-immune Tc cells are also of higher avidity than primary in vivo influenza-immune Tc cells. Thus, a restimulated memory Tc cell population interacts with targets with greater avidity than does a recently activated naive population.