專題討論16:子宮頸癌疫苗之新進展

S16-2
Immunology of Human Papillomavirus Infection
黃立民
Division of Infectious Diseases, Department of Pediatrics, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan

  Human papillomavirus (HPV) is a common agent for genital infection with the potential to develop malignancies in anogential regions, especially cervical cancer in women. Almost 80% of women with sexual life have been infected with HPV at least once in their life time. Most women clear HPV infection within a few months, however, a small proportion of them harbor the virus for months to years and may develop malignancy as a consequence. Cell-mediated immunity is the key in the protection of HPV in natural infection. Not surprisingly, HPV evolves many ways to evade the immune surveillance. Strategies used by HPV to combat immune surveillance include limiting expression of viral proteins until later stages of epithelial differentiation, undergoing non-lytic replication, and downregulating the expression of important receptors on cells of the innate immune system. Furthermore, several proinflamatory proteins that are related to activation of cytotoxic T lymphocytes are decreased during chronic HPV infection. Interestingly, prophylactic HPV vaccines have shown amazing efficacy against HPV infection and HPV-related malignancies. All the evidence so far suggests neutralizing antibodies play a pivotal role in vaccine-conferred protection. Transudation or exudation of neutralizing antibodies to the site of infection probably is the mechanism underlying this protection. Still, many aspects of the interactions between HPV and the host immune system remain unknown, further studies to elucidate this interaction is important for successful control of HPV infection in human.