[1] CHILDRENS HOSP MED CTR,DIV CELL BIOL,BOSTON,MA 02115
[2] NETHERLANDS CANC INST,1066 CX AMSTERDAM,NETHERLANDS
[3] COLUMBIA UNIV COLL PHYS & SURG,DIV INFECT DIS,NEW YORK,NY 10032
[4] HARVARD UNIV,SCH MED,DANA FARBER CANC INST,MOLEC IMMUNOL LAB,BOSTON,MA 02115
[5] HARVARD UNIV,SCH MED,DANA FARBER CANC INST,DIV TUMOR IMMUNOL,BOSTON,MA 02115