1. Immunology and Allergy Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
2. Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.
3. Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
4. GSK Vaccines, Siena, Italy.
5. GSK Vaccines, Rockville, MD 20850, USA.