1. Division of Infectious Diseases, National Key Laboratory of Biotherapy/Collaborative Innovation Center of BiotherapyWest China Hospitals, Sichuan UniversityChengdu610041 China
2. Laboratory of Cell BiologyCenter for Cancer Research, National Cancer Institute, NIHBethesda MD20892, USA
3. Enteric Diseases DepartmentInfectious Diseases Directorate, Naval Medical Research CenterSilver Spring MD20910‐7500 USA
4. Department of PediatricsUniformed Services University of the Health SciencesBethesda MD20814‐4799 USA