| HK-2 (human kidney 2) is a proximal tubular cell (PTC) line derived from normal kidney. The cells were immortalized by transduction with human papilloma virus 16 (HPV-16) E6/E7 genes. The recombinant retrovirus vector pLXSN 16 E6/E7 containing the HPV-16 E6/E7 genes was used to transfect the ectotropic packaging cell line Psi-2. Virus produced by the Psi-2 cells was used to infect the amphotropic packaging cell line PA317 (see ATCC CRL-9078). Virus produced by the PA317 cells was used to transduce primary PTCs. Although pLXSN 16 E6/E7 also confers resistance to neomycin, selection in G418 was not used to isolate transduced clones. The cell line appears to be derived from a single cell based on Southern and FISH analysis. The E6/E7 genes are present in the HK-2 genome as determined by PCR. The cells retain a phenotype indicative of well differentiated PTCs. They are positive for alkaline phosphatase, gamma glutamyltranspeptidase, leucine aminopeptidase, acid phosphatase, cytokeratin, alpha 3,beta 1 integrin, and fibronectin. The cells are negative for factor VIII related antigen, 6.19 antigen and CALLA endopeptidase. HK-2 cells retain functional characteristics of proximal tubular epithelium such as Na+ dependent / phlorizin sensitive sugar transport and adenylate cyclase responsiveness to parathyroid, but not to antidiuretic hormone. The cells are capable of gluconeogenesis as evidenced by their ability to make and store glycogen. HK-2 cells are anchorage dependent. The cells will not grow in methylcellulose, soft agar or suspension. HK-2 cells can reproduce experimental results obtained with freshly isolated PTCs. | 
