PLAYING OFFENSE: T cells, like the one pictured here, do not attack cancer cells when in the presence of certain signals. New research shows that what was thought to be a suppressive signal may actually help activate an anticancer immune attack. NIAID
J.B. Mumm et al., “IL-10 elicits IFN?-dependent tumor immune surveillance,” Cancer Cell, 20:781-96, 2011.
The cytokine IL-10 was previously thought to contribute to a tumor’s ability to suppress the immune system because of its role in reducing inflammation. But John Mumm, Martin Oft, and colleagues at Merck Research Labs have discovered that IL-10 actually has predominantly the opposite effect: it activates CD8+ T cells to attack tumors.
Mumm first began to doubt IL-10’s immunosuppressive role when he found that the cytokine activated human CD8+ T cells in vitro. Then, the team discovered that mice lacking IL-10 had more—and more lethal—tumors, while mice overexpressing IL-10 had no tumors.
The researchers found that IL-10 induces the production of additional cytotoxic enzymes by CD8+ T cells inside tumors, ...
