The Role of Semen in the Transmission of Genital Human Papillomaviruses.

The significance of semen in the transmission of genital human papillomavirus (HPV) infections was investigated. The suitability of dot blot and Southern blot hybridisation assays for use in the detection of HPV DNA in semen was assessed. HPV6/11 DNA was demonstrated by Southern blot hybridisation in semen from patients with intrameatal warts but was not detected in specimens from males attending an Assisted Conception Unit (ACU). HPV16 and 18 DNA were not detected by Southern blot hybridisation in either population. Investigations were performed to identify the component of semen with which HPV DNA was associated. When pellet and supernatant fractions of HPV-positive semen were tested by Southern blot hybridisation, HPV positivity was predominantly associated with the cellular pellet suggesting that the virus was cell-associated rather than present as free virions. Semen specimens were fractionated on Percoll gradients. HPV positivity was shown to correlate with the presence of cellular material. Attempts to visualise HPV-infected cells using immunocytochemistry and in situ hybridisation were unsuccessful. The polymerase chain reaction (PCR) was investigated for the detection of HPV DNA in clinical specimens. Reaction conditions were optimised for use of PCR in epidemiological studies. PCR was used to detect HPV11, 16 and 31 DNA in cervical material from patients attending a Family Planning Clinic (FPC). HPV16 was the most prevalent type, detected in 38% of specimens tested. Semen from GUM clinic patients and from ACU patients were tested by PCR for HPV types 11 and 16. HPV16 was the most prevalent, found in 83% and 30% of specimens, respectively. PCR was used in attempts to localise penile HPV infection by testing scrapes from the urethra and glans penis of GUM clinic patients. Neither HPV11 or HPV16 was associated particularly with urethral or external penile surfaces although interpretation was difficult due to differences in sampling method efficiencies