1. Department of Biotechnology; The Catholic University of Korea; 43-1 Yeokgok-Dong Wonmi-Ku Bucheon 420-743 Korea
2. Department of Microbiology; University of Ulsan, College of Medicine; Seoul 138-736 Korea
3. Department of Virology National Institute of Health; 5 Nokbun Dong, Eunpyung-Ku; Seoul 122-701 Korea