1. Glycobiology Research and Training Center,
Departments of Medicine and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California,
United States
2. Department
of Chemistry, University of California,
Davis, California 95616, United States
3. Virology Division, Department of Infectious Diseases
and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands