[1] Univ Utrecht, Med Ctr, Wilhelmina Childrens Hosp, Dept Pediat, NL-3584 EA Utrecht, Netherlands
[2] Univ Utrecht, Fac Vet Sci, Dept Immunol, NL-3584 EA Utrecht, Netherlands
[3] Natl Vaccine Inst, Bilthoven, Netherlands
[4] Netherlands Canc Inst, Div Immunol, NL-1066 CX Amsterdam, Netherlands