1. Developmental Therapeutics Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania;
2. Program in Molecular and Cell Biology and Genetics, Drexel University College of Medicine, Philadelphia, Pennsylvania; and
3. Temple University School of Medicine, Philadelphia, Pennsylvania; and
4. Immune Cell Development and Host Defense Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania;
5. Program in Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania