1. Canadian Blood Services, R&D Department, and Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, 1800 Alta Vista Drive, Ottawa, Ontario K1G 4J5, Canada, Pasteur Mérieux Connaught, 1755 Steeles Avenue West, North York, Ontario M2R 3T4, Canada, and Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada, and Cancer Biology Research Group, Department of Biochemistry, University of Calgary, Calgary, Alberta T2N 4N1, Canada