CD8A and infection: Several studies have suggested that the route of infection or vaccination will influence the trafficking potential of T cells following activation, a concept often referred to as “imprinting.” For example, CD8+ T cells activated in the draining lymph node following infection of the skin with Vaccinia virus begin synthesizing P- and E-selectin ligands, whereas the same antigen-specific CD8+ T cells activated in mesenteric lymph nodes when Vaccinia virus is delivered by intraperitoneal injection do not (86).