| Popis: |
Acquired immunity against viruses relies on the activation of virus-specific T cells to combat and clear the virus from the infected host. CD8 T cells are essential to this process, due to their ability to differentiate between self and non-self antigens presented by class I major histocompatibility antigens (MHC I) found on the surface of the majority of nucleated cells (Margulies 1999; Germain 1999; Ahmed and Biron 1999). Virus-specific CD8 T cells that encounter viral antigen in the context of the proper MHC I must proliferate, migrate into areas of infection, and perform effector functions, which include the production of interferon gamma (IFN-γ) and the cytolysis of infected cells (Ahmed and Biron 1999). Much of our understanding of this process has been obtained using the lymphocytic choriomeningitis virus (LCMV) system. The immune response to an acute LCMV infection of mice is associated with a massive expansion of CD8 T cells, fueling a debate about how much of this response is antigen-specific and how much might be a consequence of “bystander” T cell activation. |
