We show that exposure of CD8+ T-cells to substrate-immobilized CCL21 [a potent chemokine with multiple effects on T-cell migration, recruitment, and activation (25, 30–32, 33)] and ICAM1 [an adhesion molecule that activates LFA1-mediated signaling (22, 29)] induces a dramatic shift in T-cell organization, accompanied by major enhancement of their proliferation, intrinsic killing efficiency in culture, and tumor suppression in vivo. The gene discussed is CCL21; the disease is neoplasm.