Mucosal immunity of the female genital tract after HPV infection and vaccination

Abstract

Human papillomavirus is one of the most common sexually transmitted pathogens. HPV infections are associated with the development of cervical cancer, other genital cancers and oro-pharyngeal cancer. HPV vaccination is implemented in the Dutch national immunization program since 2010 for girls 12 years of age in a 2+1 schedule. Vaccine-derived HPV-specific antibodies in the systemic circulation probably transudate and/or exudate to the genital and oral mucosa, the sites were HPV infections take place. Antibodies induced by the vaccine, a virus-like particle composed of the major L1 capsid protein, are thought to be responsible for the protection against subsequent infection and cervical intraepithelial neoplasia (CIN). Although the HPV vaccine induces a strong immunogenic response, the level of antibodies in serum after natural infection is much lower and it is not yet clear whether they can protect against HPV (re)infections. Moreover, only 50-70% of infected individuals seroconvert. In HPV infections there is no viremia, and free virus particles are shed from the squamous epithelia surfaces with poor access to vascular and lymphatic channels and thus to the lymph nodes, were immune responses would be initiated. This is reflected in the time needed for IgG seroconversion, which is 6-12 months for HPV16 after the detection of HPV16 DNA. The mucosal immune system is the first barrier against HPV infections, however, information about the roll of the mucosal immune system after HPV infection is scarce. In this literature study, we will focus on the genital and oral mucosal immune responses derived after HPV infection and vaccination.