[1] Univ Amsterdam, Acad Med Ctr, Expt & Clin Immunol Lab,CLB, Dept Clin Viroimmunol,Sanquin Blood Supply Fdn, NL-1105 AZ Amsterdam, Netherlands
[2] Univ Utrecht, Dept Theoret Biol, Utrecht, Netherlands
[3] Univ Amsterdam, Acad Med Ctr, Dept Human Retrovirol, NL-1105 AZ Amsterdam, Netherlands