1. Immunology and Virology Research Group of the Wisconsin Regional Primate Research Center
2. Department of Pathology and Laboratory MedicineUniversity of WisconsinMadisonWI53706U.S.A.
3. Department of Medical Microbiology and ImmunologyUniversity of WisconsinMadisonWI53706U.S.A.
4. Department of Human OncologyUniversity of WisconsinMadisonWI53706U.S.A.
5. Department of Pathobiological SciencesUniversity of WisconsinMadisonWI53706U.S.A.