Jump-starting tumor-specific T cells

Vaccination with tumor antigens causes tumor regression in some melanoma patients despite negligible expansion of vaccine-specific T cells. Vaccination may instead result in the expansion of T cells specific for tumor antigens not contained in the vaccine, thus facilitating tumor regression, according to two articles from Pierre Coulie and colleagues on pages 241 and 249.

Tumor-specific T cells can be detected in the blood and the tumors of many melanoma patients, and yet these cells are unable to kill the tumor. What causes the impotence of these T cells is a mystery. Equally mysterious is why vaccination against tumor-specific antigens sometimes causes regression without expanding large numbers of vaccine-specific killer T cells.Pierre Coulie's group studied the specificity of antitumor T cell responses in patients vaccinated with a tumor antigen called MAGE-3. In one patient whose...