1. Institute of Virology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, Slovak Republic and C.N.R.S.-Institut de Recherche sur le Cancer, Villejuif-Cedex, France
2. Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University, Mlynska Dolina B
3. Institute of Virology, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, Slovak Republic
4. C.N.R.S.-Institut de Recherche sur le Cancer-Laboratoire de Cytometrie, Villejuif-Cedex, France
5. C.N.R.S.-Institut de Recherche sur le Cancer, Villejuif-Cedex, France