Local cellular immunity in the draining lymph nodes of mice after immunization with histocompatibility alloantigens

Mice immunized with allogeneic cells exhibit a local component of cellular immunity that is confined to lymph nodes draining the site of immunization. After immunization of C3H mice by skin grafting or by i.p. or footpad injection of F1 hybrid spleen cells, draining lymph nodes show increased responsiveness toward the immunizing histocompatibility determinants for at least 3 months after immunization. This local component of immunity is not detected in a traditional graft-versus-host (GVH) assay of splenomegaly. To demonstrate this immunity, we used a GVH assay in which pieces of whole lymph nodes were grafted onto F1 hybrid host kidneys. The enlargement of each grafted node piece is taken as the measure of its immunological responsiveness. We interpret our results to indicate that this node-onto-kidney assay detects the contribution of a relatively immobile donor cell population that exerts its effects in lymph nodes local to, but not distant from, the site of immunization.