1. Research Service, Harry S Truman Memorial VA Hospital, University of Missouri, Columbia, MO 65212, USA
2. Department of Internal Medicine, School of Medicine, University of Missouri, Columbia, MO 65212, USA
3. Department of Pathology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
4. Department of Immunology, Juntendo University School of Medicine, Tokyo, Japan
5. Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA