A cocktail of antibodies and proteins can wipe out large tumours in mice — even if the tumours are not particularly visible to the immune system.
Immunotherapies unleash immune-system responses against cancer, but generally fail against large, established tumours in mice. Dane Wittrup and Darrell Irvine at the Massachusetts Institute of Technology in Cambridge and their colleagues cooked up an immunotherapy with four ingredients: a tumour-targeting antibody, the immune-stimulating protein interleukin-2, a vaccine containing fragments of tumour proteins, and an antibody that blocks an immunosuppressive protein called PD-1.
This unleashed antibodies and immune cells called T cells against the tumour; these even attacked tumour proteins that were not targeted directly by the cocktail. The treatment worked against both tumours transplanted into mice and large tumours grown in mice, which are typically less visible than transplanted tumours to the mouse immune system.