1. The authors are at the Curie Institute, 26 rue d'Ulm, 75245 Paris Cedex 05, France. L. Fetler is in the Laboratoire Physico-Chimie Curie, CNRS UMR 168, Institut Curie, Paris, France.
2. S. Amigorena is in the Immunité et Cancer, INSERM U365, Institut Curie, Paris, France.