Strong cytotoxic T lymphocyte responses to a macrophage inflammatory protein 1alpha-expressing tumor: linkage between inflammation and specific immunity.

Leukocyte infiltration is an important histological sign of resistance to tumors. However, it is unclear whether local inflammatory responses can promote specific antitumor immunity. Here we report that local expression of macrophage inflammatory protein 1alpha, which results in strong inflammation of leukocytes in tumors, leads to the induction of strong antitumor CTL responses. The induction of CTL effectors requires co-stimulatory molecules B7-1 and/or B7-2 on host antigen-presenting cells but not on the tumors. These results establish a critical linkage between inflammation and specific immunity.