VRC-WEVVLP073-00-VP(National Institute of Allergy & Infectious Diseases)

M2e VLP was previously described as a vaccine that incorporates the extracellular region of the matrix 2 protein (M2e), which is highly conserved amongst all the strains of influenza. In this study, we analyzed activation status of dendritic cells (DCs) after exposure to M2e VLP, stimulating DCs with M2e VLP and co-culturing the stimulated DCs with T cells to observe innate and adaptive immune responses. The M2e VLP microparticle was prepared by encapsulating into a polymer matrix using the one-step spray drying method. Adjuvants Alhydrogel®, MPL-A® or Addavax^TM were used to enhance the DC stimulatory effects by the M2e VLP microparticle. The M2e VLP microparticle yield was found to be 92% and the encapsulation yield was around 84% with a size of approximately 2.78 μm. There was no short-term cytotoxicity found in DCs and macrophages with concentrations up to 1500 μg/mL of M2e VLP microparticle, however long-term exposure resulted in 25% decrease in viability of cells with concentrations more than or equal to 500 μg/mL. The M2e VLP microparticle vaccine with Alhydrogel® and MPL-A® induced high levels of TNFα in both DCs and macrophages. The high levels of MHC I, II, CD28, B7-1, ICAM-1, LFA-1 expression and IL-12 release in the M2e VLP microparticle group with Alhydrogel® suggests that the M2e VLP vaccine with this adjuvant activated T cells via the Th2 pathway. The increased expression of MHC I, II, CD40, CD154, ICAM-1 and LFA-1 on DCs and the release of IL-12 in the M2e VLP microparticle culture of DCs with MPL-A® demonstrated that the M2e VLP vaccine with this adjuvant activated T cells via the Th1 pathway. The decrease in fluorescence in the Alhydrogel® and MPL-A® group illustrates the proliferation of T cells took place following exposure of DCs to the M2e VLP microparticle with these adjuvants. The M2e VLP microparticle exhibited higher stimulatory responses of DCs than the M2e VLP in suspension. Furthermore, the presence of Alhydrogel® and MPL-A® enhanced the stimulatory effects of DCs by the M2e VLP microparticle (MP) vaccine.

The purpose of this study was to evaluate the effects of the route of administration on the immunogenicity and efficacy of a combined western, eastern, and Venezuelan equine encephalitis (WEVEE) virus-like replicon particle (VRP) vaccine in cynomolgus macaques. The vaccine consisted of equal amounts of WEEV, EEEV, and VEEV VRPs. Thirty-three animals were randomly assigned to five treatment or control groups. Animals were vaccinated with two doses of WEVEE VRPs or the control 28 days apart. Blood was collected 28 days following primary vaccination and 21 days following boost vaccination for analysis of the immune response to the WEVEE VRP vaccine. NHPs were challenged by aerosol 28 or 29 days following second vaccination with WEEV CBA87. Vaccination with two doses of WEVEE VRP was immunogenic and resulted in neutralizing antibody responses specific for VEEV, EEEV and WEEV. None of the vaccinated animals met euthanasia criteria following aerosol exposure to WEEV CBA87. However, one NHP control (total of 11 controls) met euthanasia criteria after infection with WEEV CBA87. Statistically significant differences in median fever hours were noted in control NHPs compared to vaccinated NHPs, providing a quantitative measure of infection and efficacy of the vaccine against a WEEV challenge. Alterations in lymphocytes, monocytes, and neutrophils were observed. Lymphopenia was observed in control NHPs.