Vaccinia virus inhibits the maturation of human dendritic cells: A novel mechanism of immune evasion

Vaccinia virus employs multiple mechanisms to evade the immune system, yet is highly immunogenic. We studied the interaction between vaccinia and huma n dendritic cells (DCs), potent APCs, DCs develop from precursor cells in t wo stages: an immature stage in which Ag uptake and processing occur, and a mature stage in which there is up-regulation of costimulatory and HLA mole cules and efficient T cell activation. Vaccinia virus undergoes an abortive replication in both stages of DCs and induces apoptotic cell death, Furthe rmore, maturation of immature DCs and consequently T cell activation are in hibited. obstruction of DC maturation may constitute a novel mechanism by w hich vaccinia attempts to evade the immune response.