1. Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas 77030;
2. Department of Molecular Virology & Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas 77030;,
3. Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, Texas 77030
4. Sabin Vaccine Institute, Washington, DC and Houston, Texas
5. Baker Institute, Rice University, Houston, Texas 77030
6. Department of Biology, Baylor University, Waco, Texas 76706