Affiliation: | 1. Institute for Virus Research, German Cancer Research Center, Im Neuenheimer Feld 280, 6900 HeidelbergF.R.G. Tel. 6221/484 611,;1. Institute for Medical Virology, University of Heidelberg, Im Neuenheimer Feld 324, 6900 HeidelbergF.R.G. Tel. 221/563008 |