Determination of freeze damage on HPV vaccines by use of flow cytometry.
The human papillomavirus (HPV) vaccines Gardasil, Silgard and Cervarix were labeled with antibodies against HPV strain 6 or 16/FITC conjugated secondary antibodies and analyzed by flow cytometry. The vaccines showed distinct peaks of fluorescent particles, and a shift towards decreased fluorescent particles was observed after incubation of the vaccines over night at -20 °C. Since parallel distributed vaccines could have longer route of transportation there is an increased risk of freeze damage for these types of vaccine. Shift in fluorescence of labeled vaccine particles was used to indicate whether parallel distributed Silgard, which is a vaccine type identical to Gardasil, was exposed to freeze damage during transportation, but no shift was observed. Additional experiments showed that the HPV vaccines could be degraded to smaller particles by citric acid/phosphate buffer treatment. The majority of particles detected in degraded Gardasil were very small indicating that the particles are HPV virus like particle (VLPs) labeled with antibodies, but Cervarix could only be degraded partially due to the presence of another type adjuvant in this vaccine. The described method may be useful in characterization of adjuvanted vaccines with respect to freeze damage, and to characterize vaccines containing particles corresponding to VLPs in size.
Biology Laboratory, Danish Health and Medicines Authority, Axel Heides Gade 1, 2300 Copenhagen S, Denmark. Electronic address: eos@dkma.dk.
Erik
E
Østergaard
Biology Laboratory, Danish Health and Medicines Authority, Axel Heides Gade 1, 2300 Copenhagen S, Denmark.
Peer Lyng
PL
Frandsen
Biology Laboratory, Danish Health and Medicines Authority, Axel Heides Gade 1, 2300 Copenhagen S, Denmark.
Eva
E
Sandberg
D005434:Flow Cytometry / Q000379:methods*; D005615:Freezing; D053918:Papillomavirus Vaccines / Q000276:immunology
D053918:Papillomavirus Vaccines
Adjuvant; Flow cytometry; Freeze damage; Human papillomavirus vaccine (HPV)