A single serum dilution enzyme-linked immunosorbent assay for determining anti-human papillomavirus (HPV) antibody titres in humans immunised with prophylactic HPV vaccines

Two types of prophylactic human papillomavirus (HPV) vaccines are currently available. However, there is no simple monitoring system for assessing acquired immunity that can cope simultaneously with large numbers of serum samples. Approximately 30% of women with normal cytology are known to be seropositive for HPV types 16 and 18 because of the high prevalence of these HPV types. Therefore, to be useful the monitoring system has to discriminate clearly between vaccine recipients and other serology groups. However, there has never been any focus on developing a method to satisfy this condition. In this study, we developed a high-throughput single-serum-dilution enzyme-linked immunoassay (ELISA) system for determining anti-HPV antibody titres following vaccination. We optimised the conditions for each ELISA step to increase its accuracy and precision and to avoid the high background of non-specific reactions that is a major problem for serology assays. The new ELISA system has superior linearity, accuracy and reproducibility. Moreover, it clearly discriminated between antibody levels in vaccine recipients and those in other serology groups such as individuals with normal cervical cytology and those with cervical cancer. Therefore, this single-serum-dilution ELISA should be very useful for assessing the acquired immunity of HPV vaccine recipients.