1Department of Molecular Virology, D.I. Ivanovsky Institute of Virology, Russian Academy of Medical Sciences, the
2Human Retrovirus Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands, the
3Vladimir V. Lukashov, Human Retrovirus Laboratory, L-1 57, Academic Medical Centre, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
4Institute of Immunology, Russian Ministry of Public Health, Moscow, Russia and the
5Byelorussian Research Institute of Epidemiology and Microbiology, Minsk, Byelorussia.