1. The Laboratories of Cell Surface Immunogenetics and Mouse Leukemia Genetics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
2. The Hospital for Special Surgery, Affiliated with the New York Hospital, Cornell University Medical College, and the Department of Pathology, Cornell University Medical College, New York, New York 10021
3. Department of Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461