1 Angela C. Colmone is the Editor of Science Immunology, American Association for the Advancement of Science, Washington, DC 20005, USA. Email: acolmone@aaas.org.
2 Federica Sallusto is the Head of the Cellular Immunology Laboratory and Director of the Center of Medical Immunology, Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland. Email: federica.sallusto@irb.usi.ch.
3 Abul K. Abbas is the Distinguished Professor in Pathology and Chair of Pathology, University of California, San Francisco, San Francisco, CA 94143-0511, USA. Email: abul.abbas@ucsf.edu.