Immortalization of primary human epithelial cells by cloned cervical carcinoma DNA containing human papillomavirus type 16 E6/E7 open reading frames.

Primary human epithelial cells were transfected with a subgenomic fragment of DNA cloned from a cervical carcinoma, containing the putative transforming genes E6 and E7 from the human papillomavirus type 16 prototype. Several immortalized cell lines were generated, all retaining tumour DNA and expressing the viral genes, suggesting that either one or both of these genes is sufficient for the immortalization of primary human genital keratinocytes.