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

Abstract

Objective: This study was designed to describe the course of IgG/IgA responses in cervical secretions and in serum one year after the first dose of intramuscular administration of the HPV16/18 AS04-adjuvant vaccine. Methods: Blood and cervical mucus samples were collected for immunologic assays, 7 months after the first doses and 1 year following the last boost vaccination (month 7) by enzyme linked immunosorbent assay (ELISA). The detection of IgG and IgA anti-HPV/VLP was developed for this purpose. Result: A total of 100% of serum samples were IgG antibody positive at 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 with the cervical samples positive for both IgG and IgA antibodies at one month and decreasing after 1 year to 33% and 29%. The median absorbance in serum and the cervix for IgG and IgA anti-HPV-VLP antibodies was significantly higher at one month after vaccination when compared to 1 year post-vaccination (P<0.0001). Conclusion: Immune responses were significant one year after immunization, however it decreased in cervical and serum samples when compared to levels observed one month after the last dose. This suggests that a vaccine booster may be necessary to increase antibody titers.

Keywords: Immunoglobulin G; immunoglobulin A; HPV; vaccine.

Figure 1

IgG/IgA Dilutions Regarding HPV-16/18 VLP in Serum. A, The Median of Absorbance Detected in Serum Sample for IgG anti-HPV-VLP at 1 Month after Vaccination (P < 0.0001). B, The median of absorbance detected in serum sample for IgG anti-HPV-VLP at 1 year after vaccination (P < 0.0001). C, The median of absorbance detected in serum sample for IgA anti-HPV-VLP at 1 month after vaccination (P < 0.0001). D, The median of absorbance detected in serum sample for IgA anti-HPV-VLP at 1 year after vaccination (P < 0.0001).

Figure 2

IgG/IgA Dilutions Regarding HPV-16/18 VLP in Cervix. A, The Median of Absorbance Detected in Cervical Mucus for IgG Anti-VLP at 1 Month after Vaccination (P < 0.0001). B, The median of absorbance detected in cervical mucus for IgG anti-VLP at 1 year after vaccination (P < 0.0001). C, The median of absorbance detected in cervical mucus for IgA anti-VLP at 1 month after vaccination (P < 0.0001). D, The median of absorbance detected in cervical mucus for IgA anti-VLP at 1 year after vaccination (P < 0.01).