1. Department of Microbiology,1
2. Department of Microbiology, Kinki University School of Medicine, Osaka-sayama, Osaka 589-8511,2
3. Institute of Immunological Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0815,3 and
4. Department of Virology I, National Institute of Infectious Disease, Toyama, Shinjuku-ku, Tokyo 162-8640,4Japan
5. Osaka Medical College,5 Takatsuki, Osaka 569-8686,