Abstract
Vaccinia virus (VV) has been most commonly used as the vaccine to protect individuals against the causative agent of smallpox (variola virus), but it also uses a number of strategies meant to evade or blunt the hosts antiviral immune response. Natural killer T (NKT) cells are a subset of immunoregulatory CD1d- restricted T lymphocytes believed to bridge the innate and adaptive immune responses. It is shown here that the VV-encoded molecules, B1R and H5R, play a role in the ability of VV to inhibit CD1d-mediated antigen presentation to NKT cells. These are the first poxvirus-encoded molecules identified that can play such a role in the evasion of an important component of the innate immune response.