Memory CD8+ cells are gatekeepers of the lymph node draining the site of viral infection

Xu R-H, Fang M, Klein-Szanto A and LJ Sigal. (2007) PNAS 104:10992-10997.

It is uncertain how immunity protects against systemic viral diseases. Here, we demonstrate that in the absence of persistent virus, not only antibodies but also recall responses by long-lived memory CD8+ cells prevent mousepox, a disease caused by ectromelia virus, a close relative of the virus of human smallpox. Moreover, we show that to protect, recall CD8+ T cells directly kill targets in the lymph node draining the primary site of infection thus curbing systemic viral spread. Therefore, our work provides the basis for a model where lymph nodes are not just organs where lymphocytes become activated and proliferate but also the sites where a major fight against virus spread takes place.