1. Cytokine and Growth Factors Section, Biotherapeutics Group, NIBSC, Medicines and Healthcare Products Regulatory Agency, Hertfordshire, United Kingdom.
2. Biostatistics Section, Technology Development and Infrastructure, NIBSC, Medicines and Healthcare Products Regulatory Agency, Hertfordshire, United Kingdom.
3. Division of Intramural Research, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland.