[1] Swiss Fed Inst Technol, Dept Biosyst Sci & Engn, CH-4058 Basel, Switzerland
[2] Swiss Fed Inst Technol, Life Sci Zurich Grad Sch, CH-8006 Zurich, Switzerland
[3] Univ Zurich, CH-8006 Zurich, Switzerland
[4] Univ Geneva, Dept Pathol & Immunol, CH-1205 Geneva, Switzerland
[5] Swiss Fed Inst Technol, Inst Microbiol & Immunol, Dept Biol, CH-8093 Zurich, Switzerland