ANTIBODY RESPONSES IN ORAL FLUID AND SERUM FOLLOWING HPV
VACCINATION
JJ Carter, Fred Hutchinson Cancer Research Center, Seattle, USA
A Rowhani - Rahbar, University of Washington, Seattle , USA
SE Hawes, University of Washington, Seattle, USA
JP Hughes, University of Washington, Seattle, USA
LA Koutsky, University of Washington, Seattle, USA
DA Galloway, Fred Hutchinson Cancer Research Center, Seattle, USA
BACKGROUND: Oral fluid sampling is simple, noninvasive, and painless, however,
immunoglobulin G levels are lower than in serum. We sought to assess the potential
utility of using oral mucosal transudate (OMT), collected by an OraSure® device, for
detection of human papillomavirus type 16 (HPV-16) specific antibodies among women
who had received a prophylactic HPV-16 L1 virus-like particle vaccine. METHODS:
Vaccine recipients (139) and placebo controls (137) who had participated in a phase IIb
randomized controlled vaccine trial (1998 – 2004) were enrolled in an extended followup study conducted in Seattle (2006 -2008). Serum and OMT specimens were collected
and tested using GST-L1 fusion proteins on a Luminex® platform. To optimize
sensitivity, a subset of OMT samples were tested twice using different protocols. The
incubation time for antigen coated beads with OMT fluid was 1 hour at room temperature
for the first test and overnight at 4 C for the second. The sensitivity and specificity of the
tests were compared by receiver operating characteristic analysis and the more sensitive
test used for testing all sera and OMT samples. RESULTS: Overnight incubation
improved assay sensitivity. Using the overnight incubation procedure on OMT collected
8.5 years after enrollment in the monovalent vaccine trial, the average median
fluorescence intensity (MFI) among the placebo recipients was 440.2 (95% confidence
interval [CI]: 370.5 – 509.9) compared with an MFI of 2,208.2 (95% CI: 1,598.4,
2,818.0) among the vaccine recipients. Although 97.8% of the sera samples from the
vaccine recipients tested positive, only 47.5% of OMT samples were positive. Six months
after administration of the licensed quadrivalent vaccine, OMT anti-HPV-16 reactivity
rose 9.8-fold among the monovalent vaccine recipients, with all OMT specimens testing
anti-HPV-16 positive. CONCLUSION: Oral fluid testing has potential as an alternative
method to venipuncture in monitoring future HPV vaccination programs.