Search

Purification is an important step in the production of viral vaccines that strongly affects product recovery and subsequent immune responses. The present study was carried out with the aim of improving the purification of infectious bursal disease virus (IBDV) by the tangential flow filtration (TFF) method. Then, the effect of the purified virus on the induction of immune responses against IBDV in specific pathogen free (SPF) chickens was investigated. The IBD07IR strain was propagated in embryonated SPF eggs. The virus was purified using a 100 kDa cassette. The quality of the recovered viruses was evaluated by titration. A total number of 60 SPF chickens were randomly divided into three groups (n = 20) and received the concentrated viral antigen, commercial live IBDV vaccine and phosphate-buffered saline at the age of 3 weeks by eye drop method. The bursa of Fabricius was examined histopathologically for possible changes. Sera were collected at 1-week intervals from day 0 until the end of 6 weeks after vaccination. The IBDV-specific antibody levels, induction of cell-mediated immunity and mRNA expression levels of cytokines were evaluated. The results showed that despite a relative raise in virus titer from 7.66 to 8.17 embryo infectious dose (EID)50 mL-1 following purification, both the purified IBDV and commercial vaccine are able to induce strong immune responses against the virus. Within a context of egg-based IBDV vaccine production, a single-step TFF can be applied for the relatively purification. This platform requires a further study in the selection of multiple membranes to optimize the operating conditions and final product. [ABSTRACT FROM AUTHOR]

The effectiveness of inactivated H9N2 influenza vaccines is doubtful due to changes in antigenic regions of the virus hemagglutinin (HA) protein. One strategy for the development of the efficacious vaccine is the use of nanoparticles that display more immunogenic regions of the influenza virus. In this study, chitosan (CS)-based nanoparticles were developed as a delivery system for intranasal immunization using recombinant H9N2 virus HA1 and nucleoprotein (NP), for the induction of humoral and cellular responses. CS-HA1 and CS-NP nanoparticles were prepared by the ionic gelation method and characterized for their physicochemical properties and shape. The immunogenicity and the protective efficacy were evaluated by measuring antibody titers, T cell proliferation response, CD4+/CD8+ ratio, and quantitative real-time RT-PCR following intranasal administration of the prepared nanoparticles alone or in combination in chickens compared to an inactivated H9N2 vaccine. The average size, surface charge, and spherical structure of the synthesized nanoparticles showed high quality. Serologic analysis revealed that the immunization of inactivated vaccine groups resulted in strong influenza antibodies, which were significantly (p < 0.05) higher compared to the other groups. The vaccinated chickens with CS-HA1+CS-NP developed higher specific anti-influenza antibodies than in those vaccinated with each of rHA1 and rNP. Administration of a combination of the protein-based nanoparticles has stimulated the activation of both CD4+ and CD8+T cells and induced a significantly higher T cell proliferation. The viral shedding was significantly lower in CS-HA1+CS-NP and inactivated vaccine groups compared with other challenged groups. The data demonstrate the potential of CS-HA1+CS-NP nanoparticles for eliciting specific influenza antibodies and conferring protection in chickens. [ABSTRACT FROM AUTHOR]

Utilizing subunit vaccines is one of the strategies to address influenza infection. Recent innovations have focused on high doses of vaccine antigens and immune enhancers or adjuvant to induce more robust and long-lasting immune responses. Here, an effect of the B cell-activating factor receptor (BAFF-R) to increase the magnitude and durability of immune responses of the recombinant HA1 (rHA1) protein against the H1N1 influenza virus was studied. The HA1 protein and the effector domain of BAFF-R were expressed in the pET-28a (+) vector. Eight-week-old BALB/c mice were equally grouped into five groups (n=20). The 15 and 25 μg/μL of rHA1 were mixed with 2 μg/μL of rBAFF-R and injected three times for vaccinated groups. Three control groups were received normal saline and two concentrations of rHA1. The ability of rBAFF-R in eliciting HA-specific antibody response and stimulating T lymphocyte proliferation to induce the cell-mediated immunity was assayed. Induction of protection was evaluated following the challenge with PR8 strain. Analysis of immune responses showed that the co-administration of rBAFF-R with rHA1 boosted HI responses to the antigen in mice, whilst it was not able to promote the T cell proliferation responses against influenza. Compared to rHA1alone, the rBAFF-R/rHA1 generated efficient protection for the animals. There were no significant differences in eliciting the immune responses in mice immunized with the lower dose of rHA1 than that with the higher dose. The data indicate the rBAFF-R can enhance the primary and memory immune responses to protect against influenza infection. [ABSTRACT FROM AUTHOR]