KERATINOCYTES IMMORTALIZED BY HUMAN PAPILLOMAVIRUS-18 EXHIBIT ALTERATIONS DEPENDENT UPON HOST GENETIC BACKGROUND AND COMPLEXITY OF VIRAL GENES TRANSFECTED

Keratinocytes immortalized by the human papillomaviruses (HPVs) vary i n cell morphology, growth properties, resistance to inducers of termin al differentiation, and karyotype. To determine the contribution of th e host cell genetic background and the HPV genes to these cellular alt erations, we have generated and characterized 6 human keratinocyte lin es from two different newborn foreskins (A and B) using either the ful l-length HPV18 genome or the isolated HPV18 E6/E7 genes. The growth pr operties of the immortalized lines were found to correlate with the co mplexity of HPV genes present in the transfected vector. Interestingly , cell lines established from foreskin A revealed common chromosomal a lterations regardless of the HPV construct utilized for immortalizatio n, and these karyotypic changes differed from those observed in cell l ines established from foreskin B, which exhibited their own characteri stic aneuploid profile. Thus, chromosomal alterations of HPV-immortali zed cells are in part determined by the host genetic background.