Immune response to human papillomavirus one year after prophylactic vaccination with AS04-adjuvanted HPV-16/18 vaccine: HPV-specific IgG and IgA antibodies in the circulation and the cervix
Neoplasms, Glandular and Epithelial
Objective: This study was designed to describe the course of IgG/IgA responses in cervical secretions and in serumone year after the first dose of intramuscular administration of the HPV16/18 AS04-adjuvant vaccine. Methods: Bloodand cervical mucus samples were collected for immunologic assays, 7 months after the first doses and 1 year followingthe last boost vaccination (month 7) by enzyme linked immunosorbent assay (ELISA). The detection of IgG and IgAanti-HPV/VLP was developed for this purpose. Result: A total of 100% of serum samples were IgG antibody positiveat a titer of 1:100 at both time periods and decreased according to the serum dilution. For serum IgA antibody, 95%were positive one month after vaccination and 79% were positive 1 year later. Similar results were observed withthe cervical samples positive for both IgG and IgA antibodies at one month and decreasing after 1 year to 33% and29%. The median absorbance in serum and the cervix for IgG and IgA anti-HPV-VLP antibodies was significantlyhigher at one month after vaccination when compared to 1 year post-vaccination (P<0.0001). Conclusion: Immuneresponses were significant one year after immunization, however it decreased in cervical and serum samples whencompared to levels observed one month after the last dose. This suggests that a vaccine booster may be necessary toincrease antibody titers.