Institution: | 1.Department of Cell and Molecular Biology, Karolinska Institutet, Berzelius väg 35, 2.Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, S-171 77, Stockholm, Sweden and 3.Department of Pathology and Infectious Diseases, Royal Veterinary College, University of London. N. Mymms, Herts. AL9 7TA, UK |