1. Department of Virology, School of Public Health, Shandong University, Jinan 250012, PR China
2. State Key Laboratory of Microbial Technology, National Glycoengineering Research Center, Shandong University, Jinan 250100, PR China
3. The Key Laboratory for Experimental Teratology of the Ministry of Education, Shandong University, Jinan 250012, PR China