[1] KAROLINSKA INST,DEPT IMMUNOL,BOX 60400,S-10401 STOCKHOLM 60,SWEDEN
[2] KAROLINSKA INST,DEPT VIROL,S-10401 STOCKHOLM 60,SWEDEN
[3] UNIV UPPSALA HOSP,DEPT PATHOL,UPPSALA,SWEDEN
[4] UNIV UPPSALA BIOMEDICUM,DEPT VIROL,UPPSALA,SWEDEN
[5] KABIGEN AB,STOCKHOLM,SWEDEN