Inflammation driven by tumor-specific Th1 cells protects against B-cell cancer

The immune system can both promote and suppress cancer. Chronic inflammation and proinflammatory cytokines such as interleukin (IL)-1 and IL-6 are considered tumor-promoting. In contrast, the exact nature of protective antitumor immunity remains obscure. In this study, we have quantified locally secreted cytokines during primary immune responses against myeloma and B-cell lymphoma in mice. Strikingly, successful cancer immunosurveillance mediated by tumor-specific CD4+ T cells was consistently associated with elevated local levels of both proinflammatory (IL-1aplha, IL-1beta, and IL-6) and T helper 1 (Th1)-associated cytokines (interferon-alpha, IL-2, IL-12). Cancer eradication was achieved by a collaboration between tumor-specific Th1 cells and tumor-infiltrating, antigen-presenting macrophages. Th1 cells induced secretion of IL-1? and IL-6 by macrophages. Th1-derived interferon-? was shown to render macrophages directly cytotoxic to cancer cells, and to induce macrophages to secrete the angiostatic chemokines CXCL9/MIG and CXCL10/IP-10. Thus, inflammation, when driven by tumor-specific Th1 cells, may prevent rather than promote cancer.

5

Haabeth OA, Lorvik KB, Hammarström C, Donaldson IM, Haraldsen G, Bogen B, Corthay A