Human papillomavirus type 16 variant lineages characterized by nucleotide sequence analysis of the E5 coding segment and the E2 hinge region

We have previously examined 29 cervical cell isolates for human papillomavi rus type 16 (HPV-16) sequence variations in the E6, L2 and L1 coding region s, and the long control region (LCR). Twenty-five of these isolates as well as 23 additional isolates are characterized here as we present the complet e E5 coding segment and the E2 hinge region. Eight amino acid variations we re observed in the E5 coding segment, 13 were identified in the E2 hinge re gion and 5 were observed in the overlapping E4 coding segment. These amino acid variations may be relevant to differences in biological functions and may result in altered humoral or cell-mediated immune responses to HPV-16 v ariants. The characterization of sequence variation within high-risk HPV ty pes might be important in the search for epidemiological correlates of cerv ical cancer risk. This work complements and extends HPV-16 genome sequence information from specific isolates previously reported by our group.