Development and immunogenic potentials of chitosan-saponin encapsulated DNA vaccine against avian infectious bronchitis coronavirus

Abstract

Infectious bronchitis (IB) is an economically important disease of poultry that also serve as model for the understanding of other coronaviruses associated diseases. IB is considered as a major challenge to the poultry industry worldwide as a result of its effect on egg production, weight gain as well as mortality. Different IBV genotypes continue to emerge, thus, the need for broad based vaccines to curb the disease. Based on bioinformatic data obtained in this study, sets of monovalent (either M41 or CR88) and bivalent DNA vaccines encoding the S1 glycoprotein from two different strains namely, M41 and CR88 were developed. The candidate vaccine was further encapsulated with a chitosan-saponin nanoparticle with the view to enhance its immunogenicity. Following in vitro characterization of the constructs, the vaccine candidates were tested in specific pathogen free (SPF) chickens. Analysis of humoral responses revealed a significant increase in anti-IBV antibody after immunization with the bivalent DNA plasmid (pBudCR88-S1/M41-S1). Likewise, cell mediated immune (CMI) response was significantly higher in vaccinated groups as compared to the unvaccinated chickens. Vaccinated chickens exhibited milder clinical signs as well as tracheal and kidney lesion scores following virus challenge as compared to the control groups. Additionally, encapsulation of the bivalent DNA vaccine with chitosan-saponin nanoparticles was found to improve protection against challenge with IBV strains M41 and CR88 as revealed by a significant reduction (p < 0.05) in oropharyngeal and cloacal virus sheddings following challenges with each of the two viruses. In contrast, monovalent IB-DNA vaccines were protective against homologous virus challenge. Moreover, nanoencasulation of the candidate vaccine was demostrated to abrogate the need for booster vaccination. In conclusion, this study demonstrates the immunogenic potentials of a bivalent IB-DNA vaccine and the use of chitosan-saponin nanoparticle to enhance its response. This development could serve as alternative strategy for the control of IB in poultry.

Comparative Evaluation of Immune Responses and Protection of Chitosan Nanoparticles and Oil-Emulsion Adjuvants in Avian Coronavirus Inactivated Vaccines in Chickens

“…The immune-stimulating properties of chitosan nanoparticles as carrier-adjuvant in vaccines, including or no, other compounds such as saponin and mannose, and either for conventional viral antigen preparations or recombinant viral protein and nucleic acid formulations, have been demonstrated in several studies, especially with regard to their ability to induce local and systemic antibodies and T-cell immune responses against viral pathogens. This includes the induction of TH1/TH2 responses, especially when the vaccine is administered via the mucosa [12,13,15,16,19,26,38,39]. The main advantage of our developed AvCoV-CS vaccine is its capacity to safely activate immune responses mediated by antibody and T cells in the mucosal and systemic compartments, since the used antigen is an inactivated virus.…”

“…Chitosan nanoparticles (CPS) have been recognized as promising carrier-adjuvant candidates for mucosal stimulation [12][13][14][15][16] and are able to drive both cell-mediated (CMI) and humoral immune responses in mucosal and systemic compartments [12,13,15,16]. Thus, CPSs have been successfully used as delivery carrier-adjuvants for several antigens and DNA preparations in diverse vaccine formulations [12,13,15,[17][18][19]. In addition, the association of CPS and inactivated AvCoV has already proven to be able to induce humoral and CMI responses at the primary site of AvCoV replication, which were correlated with decreased pathological lesions and viral loads [20], similarly to the protection afforded by live attenuated AvCoV vaccines [1][2][3].…”

A review of the antiviral activity of Chitosan, including patented applications and its potential use against COVID‐19

“…Previous studies on the role of chitosan for such uses indicate that the cationic polymer chitosan may be used as a successful biodegradable vaccine delivery adjuvant and that this characteristic may be applicable to SARS-CoV-2. Bande et al (2020) studied the use of chitosan as a vaccine adjuvant in the treatment of poultry infectious bronchitis caused by an avian coronavirus. Chitosan-saponin nanoparticles were used to encapsulate a DNA vaccine and subsequently, their immunogenicity was determined against two infectious bronchitis viruses, M41 and CR88.…”

Infectious Bronchitis Virus (Gammacoronavirus) in Poultry Farming: Vaccination, Immune Response and Measures for Mitigation

“…Promising results were obtained after the birds were inoculated with multivalent plasmid DNA vaccine (2×) followed by a single booster with a kill vaccine, with antibody titers in the prime-boost birds being considerably higher than compared to the multivalent DNA vaccine group (p < 0.01) with strong concurrent immunity against viral infection. Bande et al [78] conducted trials with monovalent (either M41 or CR88) and bivalent DNA vaccines encoding the S1 glycoprotein encapsulated within a chitosan-saponin nanoparticle to improve its immunogenicity against monovalent IB-DNA vaccines, which conferred protection against a homologous virus challenge. Another study was conducted on plasmid DNA vaccine with the plasmid construct pDKArkS1 based on the S1-spike genes of Arkansas IBV serotypes and immunization via the in ovo route was applied followed by a live vaccine after two weeks.…”