However, our initial validation studies and repeat testing of 7-month samples which had been
earlier tested together with baseline samples revealed no more than DAPT concentration 2-fold variation in GMTs between test runs and different technologists. Sequence variations between PsV prepared with the National Institutes of Health L1 plasmids and those used to construct the VLPs for the Merck cLIA and TIgG assays could also account for some variability between assays, as might the L2 component which is present in HPV 16 and 18 PsV, but not in the vaccine VLPs used in the Merck assays. In summary, our study showed high correlation between HPV antibody levels measured by the PsV NAb and the Merck cLIA and TIgG assays. All three assays have similar sensitivity for detection of post-vaccine HPV 16 antibodies, but for HPV 18 both the PsV NAb and TIgG assays are more sensitive than the cLIA. The fact that three discernible GMT endpoints (NT100, NT90 and NTpartial) were consistently derived by using a PsV NAb assay illustrates the challenges and complexities of defining immunoassay cut-offs for the assessment of HPV type-specific vaccine- and/or naturally induced antibodies. Unless assay cut-offs can be more
accurately defined and the component elements better characterized, correlates of HPV seroprotection will remain elusive. A study is in progress to assess the 10-year durability of HPV antibody responses among subjects immunized with two vs. three doses of Gardasil®. This work
was supported by grants from the Michael Smith Foundation for Verteporfin purchase Health Research (PJ-HPV-002078) and the Merck Investigator-Initiated Studies Program (IIS # 39229). The study sponsors had no role in the study design, collection, analysis and interpretation of data, writing of the report, or in the decision to submit the article for publication. We thank S. Pang and C. Buck (National Institutes of Health, Bethesda, MD) for providing HPV and reporter protein plasmids, 293TT cells, rabbit antisera, and technical advice. We acknowledge the support of Merck Research Laboratories for performing the cLIA and TIgG assessments. Author contributions: M.K., S.M., D.M., M.D., T.K., G.O., M.P. and S.D. conceived and designed the study. J.P., M.P. and K.K. developed the PsV NAb assays, and R.C., Q.S. and W.M. conducted the PsV NAb tests. A.Y. and D.C. Resminostat analyzed the data. M.K. and D.C. drafted the manuscript. All authors provided critical review for important intellectual content and approved the final version to submit for publication. Conflict of interest: Mel Krajden has received grant funding through his institution from the Merck Investigator-Initiated Studies Program. “
“Foot-and-mouth disease (FMD) remains a globally important livestock disease affecting cloven-hoofed animals. It remains enzootic in many regions, especially in developing countries where it imposes a trade barrier upon livestock and their products.