[1] HARVARD UNIV,SCH MED,DANA FARBER CANC INST,DIV TUMOR VIROL,BOSTON,MA 02115
[2] HARVARD UNIV,SCH MED,DEPT GENET,BOSTON,MA 02115
[3] RUSH PRESBYTERIAN ST LUKES MED CTR,DEPT IMMUNOL MICROBIOL,CHICAGO,IL 60612
[4] UNIV PENN,SCH MED,DEPT PATHOL,PHILADELPHIA,PA 19104