1. Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
2. Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA.
3. Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
4. Department of Immunology, University of Washington, Seattle, WA 98195, USA.
5. Department of Medicine, University of Washington, Seattle, WA 98195, USA.
6. Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.