|Title||Development of a Virosomal RSV Vaccine Containing 3D-PHAD® Adjuvant : Formulation, Composition, and Long-Term Stability|
|Author(s)||Lederhofer, J.; Lent, J. van; Bhoelan, F.; Karneva, Z.; Haan, A. de; Wilschut, J.C.; Stegmann, T.|
|Source||Pharmaceutical Research 35 (2018)9. - ISSN 0724-8741|
Laboratory of Virology
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||adjuvant - monophosphoryl lipid A - respiratory syncytial virus - single particle tracking - vaccine - virosomes|
Purpose: Characterization of virosomes, in late stage preclinical development as vaccines for Respiratory Syncytial Virus (RSV), with a membrane-incorporated synthetic monophosphoryl lipid A, 3D-PHAD® adjuvant. Methods: Virosomes were initially formed by contacting a lipid film containing 3D-PHAD® with viral membranes solubilized with the short chain phospholipid DCPC, followed by dialysis, later by adding solubilized 3D-PHAD to viral membranes, or to preformed virosomes from DMSO. Results: Virosomes formed from lipid films contained the membrane glycoproteins G and F, at similar F to G ratios but lower concentrations than in virus, and the added lipids, but only a fraction of the 3D-PHAD®. By single particle tracking (SPT), the virosome size distribution resembled that seen by cryo-electron microscopy, but dynamic light scattering showed much larger particles. These differences were caused by small virosome aggregates. Measured by SPT, virosomes were stable for 300 days. 3DPHAD ® incorporation in virosomes could be enhanced by providing the adjuvant from DCPC solubilized stock, but also by adding DMSO dissolved adjuvant to pre-formed virosomes. Virosomes with 0.1 mg/mg of 3D-PHAD®/viral protein from DMSO induced antibody titers similar to those by virosomes containing 0.2 mg/mg of DCPC-solubilized 3D-PHAD®. Conclusions: Stable 3D-PHAD® adjuvanted RSV virosomes can be formulated.