1. W.-P. Fung-Leung, J. Pang, D. Leturcq, P. A. Peterson, R. W. Johnson Pharmaceutical Research Institute, Suite 100, 3535 General Atomics Court, San Diego, CA 92121, USA.
2. C. D. Surh and S. R. Webb, Department of Immunology, IMM-4, The Scripps Research Institute, 10666 North Torrey Pines Road, La Jolla, CA 92037, USA.
3. M. Liljedahl and L. Karlsson, R. W. Johnson Pharmaceutical Research Institute at The Scripps Research Institute, IMM-23, 10666 North Torrey Pines Road, La Jolla, CA 92037, USA.