1. Committee on Immunology and Department of Pathology; Howard Hughes Medical Institute; University of Chicago; Chicago; IL; USA
2. Department of Chemistry and Biochemistry; Brigham Young University; Provo; UT; USA
3. Committee on Immunology and Department of Biochemistry and Molecular Biology; University of Chicago; Chicago; IL; USA
4. Committee on Immunology and Department of Medicine; University of Chicago; Chicago; IL; USA