ABSTRACT
In clinical practice, the low immunogenicity and low stability of the DNA plasmid vaccine candidates are two significant shortcomings in their application against infectious diseases. To overcome these two disadvantages, the plasmid expressing IL-29 (pIL-29) as a genetic adjuvant and polylactic-co-glycolic acid (PLGA) as a non-viral delivery system were used, respectively. In this study, the pIL-29 encapsulated in PLGA nanoparticles (nanoIL-29) and the pgD1 encapsulated in PLGA nanoparticles (nanoVac) were simultaneously applied to boost immunologic responses against HSV-1. We generated spherical nanoparticles with encapsulation efficiency of 75 ± 5% and sustained the release of plasmids from them. Then, Balb/c mice were subcutaneously immunized twice with nanoVac+nanoIL-29, Vac+IL-29, nanoVac, Vac, nanoIL-29, and/or IL-29 in addition to negative and positive control groups. Cellular immunity was evaluated via lymphocyte proliferation assay, cytotoxicity test, and IFN-γ, IL-4, and IL-2 measurements. Mice were also challenged with 50X LD50 of HSV-1. The nanoVac+nanoIL-29 candidate vaccine efficiently enhances CTL and Th1-immune responses and increases the survival rates by 100% in mice vaccinated by co-administration of nanoVac and nanoIL-29 against the HSV-1 challenge. The newly proposed vaccine is worth studying in further clinical trials, because it could effectively improve cellular immune responses and protected mice against HSV-1.
Subject(s)
Herpesvirus 1, Human , Nanoparticles , Vaccines, DNA , Animals , Mice , Glycols , Cytokines , Mice, Inbred BALB CABSTRACT
During the 15 years since the discovery of type III human interferons [IFN-λ1(IL-29), IFN-λ2(IL-28A), and IFN-λ3(IL-28B)], numerous biological properties such as anticancer, antiviral, and immunomodulatory activities of this new IFN family have been investigated. Several studies have shown that the encapsulation of pcDNA with PLGA nanoparticles (NPs) protects them against DNase enzyme action and increases the efficiency of gene delivery to the cells. The purpose of this study was to encapsulate pcDNA encoding IFN-λ1 (pIFN-λ1) with a simple and cost-effective method using PLGA NPs. The pIFN-λ1-loaded PLGA NPs were produced by a double-emulsion-solvent evaporation method and characterized in terms of size, size distribution, and zeta potential by DLS and morphologically by SEM and TEM. The bioactivity of NPs was also examined by fluorescent microscopy. The results showed that IFN-λ1 expressed by HEK293T cells could protect HepC-2 cells from the cytopathic effects of EMCV. The NPs were spherical in shape with a mean diameter of 380 ± 3 nm, a zeta potential of -3.3 ± 7.6 mV, an encapsulation efficiency of 75 ± 5%, and a loading capacity of 0.83 ± 0.06. The NPs were also bioactive and easily engulfed by RAW264.7 cells. The pIFN-λ1 could be sustainably released from NPs. Due to the facility and affordability of encapsulation of pIFN-λ1 in the PLGA NPs proposed in this study and the advantages of encapsulation by PLGA, it appeared rational to use pIFN-λ1-loaded NPs instead of naked pIFN-λ1 to determine other unexplained activities of this new cytokine or to use it as an alternative or adjunct to current IFN-α therapy.
ABSTRACT
BACKGROUND: Using molecular adjuvants offers an attractive strategy to augment DNA vaccine-mediated immune responses. Several studies have revealed that an efficient HCV vaccine model should be able to induce both humoral and cell mediated immune responses targeting the conserved regions of the virus to circumvent the immune escape mutants. The beta chemokine Macrophage Inflammatory Protein 3-beta (MIP-3beta) is a key modulator of dendritic cells (DCs) and T-cells interaction, functions during immune response induction and is secreted specifically by cells in the lymphoid tissues. OBJECTIVES: In the present study, we questioned whether co-administration of MIP-3beta gene could enhance the immune responses to HCV core in DNA vaccination. MATERIALS AND METHODS: Expression and biological activity of MIP-3beta expressing plasmid were evaluated by ELISA and transwell migration assays, respectively. HCV core DNA vaccine ± plasmid expressing MIP-3beta were electroporated subcutaneously to the front foot pads of BALB/c mice on days 0 and 14, and HCV core protein booster was applied to all core-DNA-vaccine received mice on the day 28. Both cell mediated immunity (proliferation, IFN-γ and IL-4 cytokine release, IFN-γ ELISpot and cytotoxic Granzyme B release assays) and humoral immune responses (total IgG and IgG2a/IgG1 subtyping) were evaluated ten days after final immunization. RESULTS: Mice covaccinated with MIP-3beta elicited an enhanced Th1 biased systemic immune response as evidenced by higher IFN-γ/IL-4 and anti-core IgG2a/IgG1 ratio, lymphoproliferation, strong cytolytic GrzB release and enhanced population of IFN-γ producing immunocytes. Likewise, the humoral immune response assumed as the total anti-core IgG level was augmented by MIP-3beta co-delivery. CONCLUSIONS: These results exhibited the immuno potentiator effects of MIP-3beta plasmid when coadministrated with the HCV core DNA vaccine. Complimentary studies integrating MIP-3beta as a genetic adjuvant in HCV-core-DNA vaccination models are warranted.
