RESUMEN
The highly pathogenic avian influenza H5N1 virus continues to spread globally in domestic poultry with sporadic transmission to humans. The possibility for its rapid transmission to humans raised global fears for the virus to gain capacity for human-to-human transmission to start a future pandemic. Through direct contact with infected poultry, it caused the largest number of reported cases of severe disease and death in humans of any avian influenza strains. For pandemic preparedness, use of safe and effective vaccine adjuvants and delivery systems to improve vaccine efficacy are considered imperative. We previously demonstrated CaPtivate's proprietary CaP nanoparticles (CaPNP) as a potent vaccine adjuvant/delivery system with ability to induce both humoral and cell-mediated immune responses against many viral or bacterial infections. In this study, we investigated the delivery of insect cell culture-derived recombinant hemagglutinin protein (HA) of A/H5N1/Vietnam/1203/2004 virus using CaPNP. We evaluated the vaccine immunogenicity in mice following two intramuscular doses of 3 µg antigen combined with escalating doses of CaPNP. Our data showed CaPNP-adjuvanted HA(H5N1) vaccines eliciting significantly higher IgG, hemagglutination inhibition, and virus neutralization titers compared to non-adjuvanted vaccine. Among the four adjuvant doses that were tested, CaPNP at 0.24% final concentration elicited the highest IgG and neutralizing antibody titers. We also evaluated the inflammatory response to CaPNP following a single intramuscular injection in guinea pigs and showed that CaPNP does not induce any systemic reaction or adverse effects. Current data further support our earlier studies demonstrating CaPNP as a safe and an effective adjuvant for influenza vaccines.
Asunto(s)
Anticuerpos Neutralizantes/biosíntesis , Anticuerpos Antivirales/biosíntesis , Fosfatos de Calcio/administración & dosificación , Subtipo H5N1 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/administración & dosificación , Nanopartículas/administración & dosificación , Adyuvantes Inmunológicos/administración & dosificación , Animales , Femenino , Cobayas , Vacunas contra la Influenza/inmunología , Masculino , Ratones , Ratones Endogámicos BALB C , Vacunas de Subunidad/administración & dosificaciónRESUMEN
Systemically administered interferons are rapidly cleared from the circulation thus requiring frequent dosing to maintain the therapeutic levels of circulating interferon. This is particularly problematic for their use in the treatment of chronic diseases. The purpose of this study was to evaluate the potential of proprietary calcium phosphate (CaP) particles to deliver biologically active interferon alpha (IFNα) via the lungs into systemic circulation. Recombinant human IFNα-2a was formulated with proprietary CaP particles. In vitro biological activity of IFNα was assessed for its potential to activate IFN-induced cellular pathways in HEK-Blu-IFN α/ß cell cultures. Antiviral activity was evaluated against vesicular stomatitis virus (VSV) infection of HeLa cells. Male BALB/c mice were used to evaluate the absorption of IFNα from CaP-IFNα across the lungs following intratracheal (IT) instillation. Serum IFNα concentrations up to 9 h post-treatment were determined. Data were analyzed to obtain pharmacokinetic (PK) parameters. Data from these studies indicated that IFNα formulated with CaP retains its biological activity, and it is transported into circulation in a dose-dependent manner. PK analysis showed larger than two-fold area under the serum concentration-time curve (AUC) for CaP-IFNα compared to non-formulated IFNα administered IT. The IFNα formulated with CaP had two-fold longer half-life (t1/2) and mean residence time (MRT) relative to IFNα alone administered by injection. Clearance of CaP-IFNα was slower than IFNα administered IM or IT. Relative bioavailability of CaP-IFNα was 1.3-fold of IFNα injection and twofold of IFNα administered IT. Furthermore, inhalation of aerosolized CaP did not indicate any lung toxicity in animals.