A POLYMERASE CHAIN-REACTION (PCR) INVESTIGATION OF ORAL VERRUCAE WHICH CONTAIN HPV TYPE-2 AND TYPE-57 BY IN-SITU HYBRIDIZATION

The polymerase chain reaction (PCR) and direct DNA sequencing have bee n used to identify strain variants of HPV types 2a/57 in formalin-fixe d sections of human oral verrucae, where the virus had previously been detected by both immunofluorescence and in situ hybridization. By emp loying type-specific and type-common PCR primers we show that these le sions contain a mixture of viral DNAs which vary by up to 27% in DNA s equence, in a region where the variation between HPV types 2a and 57 i s only 4%. The extra discriminatory power of fluorescent sequencing in dicates that the lesions may also contain wildtype HPV2a/57 DNA which could provide a helper function for defective viral DNA molecules or i ndicate a mosaic origin for the lesions.