Using a novel live chimeric virus vaccine candidate, BinJ/DENV2-prME, we explored a panel of pharmaceutical excipients to mitigate vaccine loss during the drying and storage process


Using a novel live chimeric virus vaccine candidate, BinJ/DENV2-prME, we explored a panel of pharmaceutical excipients to mitigate vaccine loss during the drying and storage process. explored a panel of pharmaceutical excipients to mitigate vaccine loss during the drying and storage process. This screening identified human serum albumin (HSA) as the lead stabilizing excipient. When bDENV2-coated HD-MAPs were stored at 4 C for a month, we found complete retention of vaccine potency as assessed by the generation AMG-510 of potent virus-neutralizing antibody responses in mice. We also demonstrated that HD-MAP wear time did not influence vaccine deposition into the skin or the corresponding immunological outcomes. The final candidate formulation with HSA maintained ~100% percentage recovery after 6 months of storage at 4 C. genus and is transmitted via the bite of AMG-510 an infected mosquito [2]. Flaviviruses primarily infect skin Langerhan cells and dendritic cells, which travel to the lymph nodes, and from there, the virus is disseminated throughout the body [3]. DENV infection results in a broad spectrum of symptoms, ranging from dengue fever (DF), a self-limiting illness, to severe dengue with plasma leakage, severe bleeding, or organ impairment [4]. With 3 billion people living in regions of virus transmission and the increased risk of viral transmission to travelers to endemic countries, the development of a vaccine against DENV has been an ongoing challenge since its first isolation in 1943 [5]. While Dengvaxia licensure in 2016 has been a major advance in dengue vaccine development, limitations around its efficacy have required the ongoing development of alternative vaccines [6,7,8]. Intensive research has continued involving a range of vaccine approaches, with Takedas TAK-003 vaccine candidate seeking licensure for Europe and dengue-endemic countries, marking another important development for dengue vaccines [9]. Intradermal (ID) vaccination delivers antigen into the dermal layer of the skin, targeting the DCs, and eventually carries it to the draining lymph nodes, inducing a similar response to that which occurs IL8 when naturally infected with DENV via a mosquito bite [10,11]. However, the standard Mantoux ID vaccination is difficult to reproducibly perform without the aid of specialized needles (MicronJet and BD Soluvia Device) [10,12,13]. In recent years, advances in nano- and microfabrication processes have led to the development of specialized delivery technologies to overcome the technical challenges associated with ID vaccinations. Microarray patches, ranging from dissolving to solid microprojections, have been developed as alternative delivery platforms that offer a variety of benefits over the standard syringe and needle injection methods [14,15,16,17,18,19,20,21,22,23]. The HD-MAP is a 1 cm2 molded polymer patch, consisting of 5000 conical microprojections, each 250 m in length [24]. The HD-MAP has been designed to target vaccine antigens to the dermal and epidermal layers of the skin, which are rich in antigen-presenting cells. To overcome the viscoelastic property of the skin, the HD-MAP is applied dynamically using a custom spring-loaded applicator. As a function of this application process, localized cell death is caused by the microprojections penetrating the skin, releasing damage-associated molecular patterns (DAMPs). The colocalization of the DAMPs with the delivered vaccine results in enhanced immune responses [8,25]. In comparative dose-matched studies with standard injection methods using mouse models and in Phase I clinical AMG-510 trials, the HD-MAP has been shown to elicit potent antibody responses using AMG-510 a fraction of a dose for a wide range of vaccines [17,24,26,27]. One of the unique features of the HD-MAP is the dry coating of the vaccine onto the surface of the microprojections. As a function of this drying, vaccines can be stabilized for extended periods with reduced dependence on the cold chain [26,28,29,30,31]. However, given the dry-coating process, there is a need to ensure the stability of the vaccine in a solid state upon dry down through careful selection and screening of excipients. Our group has recently demonstrated the effective delivery of a novel chimeric Dengue virus vaccine candidate, BinJ/DENV2-prME (bDENV2), by the HD-MAP. The targeted delivery of an unadjuvanted, single dose of the vaccine to the skin raised potent immune responses that afforded complete protection to DENV challenge in the AG129 dengue mouse model when compared to the ID vaccinated group [27]. While these results were promising, retaining quaternary epitopes upon storage in their dry state was challenging. Using bDENV2, we explored 26 different classes and types of generally regarded as safe (GRAS) pharmaceutical excipients in various concentrations and identified those that would mitigate vaccine loss during the drying process and storage. The final candidate formulation with human serum albumin (HSA) maintained close to 100% recovery after 6 months of storage at 4 C. 2. Materials and Methods 2.1. Animal Ethics Animal experiments were approved by the University of Queensland (UQ) animal ethics committee (AEC no.: SCMB/AIBN/322/19/NHMRC) and performed in accordance with the National Health and Medical Research Council guidelines. Animals were maintained under specific pathogen-free conditions in the UQ Biological Resources animal housing facility. 2.2..