Adult Syrian hamster kidney cells were transfected with a mixture of plasmids containing human papillomavirus type 16 (HPV16) E6/E7 open reading frames (ORFs), activated Ha-ras gene and neomycin resistance gene. From these cultures two lines were isolated which were oncogenic for newborn and 5-day-old but not for 3-week-old hamsters. Sublines oncogenic for 3-7-week-old hamsters were derived from tumours formed in animals inoculated within 5 days of birth. The cells contained HPV 16 DNA in an integrated form and HPV16 transcripts. The transcript patterns in low and high oncogenicity sublines were different. Very few tumour-bearing animals possessed antibodies reactive with E6- and E7-derived synthetic peptides. On the other hand a majority of these animals gave a positive reaction in the lymphoproliferation assay with either E6 and E7 peptides or extracts from the transformed cells.

Department of Experimental Virology Institute of Haematology and Blood Transfusion Prague Czech Republic

Metastatic MHC class I-negative mouse cells derived by transformation with human papillomavirus type 16