Oral Immunization With Plant-Based Vaccine Induces a Protective Response Against Infectious Bursal Disease

Abstract

Infectious bursal disease virus (IBDV) is the etiological agent of an immunosuppressive and highly contagious disease that affects young birds causing important economic losses in the poultry industry worldwide. We have previously developed a plant-based vaccine candidate for infectious bursal disease (IBD) that is able to protect against infection with IBDV when administered through intramuscular (im) route. Given that oral vaccination is non-invasive and stimulates the immunity of the mucosal gastrointestinal surface, the initial site of contact and entry of IBDV, the aim of this work was to study if our immunogen was also able to elicit a protective immune response when orally administered. We demonstrated that 85% of the animals that received two oral doses of the vaccine formulation and all animals that were orally boosted after an im prime scheme developed virus neutralizing antibodies and were protected against IBDV infection, evidenced by the bursa/body weight (BB) ratio, absence of T-cell infiltration, and low viral load in bursa. Although mild to moderate bursal damage was observed in some of these animals, these lesions were not as severe as the ones observed in challenged control groups, which also presented signs of acute inflammation, bursal atrophy, T-cell infiltration, and absence of viral clearance. These results show that two immunizations with our recombinant immunogen are able to induce a specific and protective immune response in chicken against IBDV when orally administered in a prime/boost scheme or when the oral boost follows an im prime scheme. In conclusion, our oral plant-based vaccine candidate could represent a viable alternative to conventional vaccines and is of great interest to the poultry industry.

Salmonellosis: An Overview of Epidemiology, Pathogenesis, and Innovative Approaches to Mitigate the Antimicrobial Resistant Infections

“…Vaccines help reduce the incidence of infectious diseases worldwide including fowl (avian) cholera, coronavirus, anthrax, polio, norovirus, Rift Valley fever, and rabies [407][408][409][410][411]. The mode of action of vaccines depends on their formulations [412]. For example, (1) Live attenuated vaccines contain a weakened, live version of the pathogen, capable of eliciting an immune response without causing disease [413].…”

Advances in Poultry Vaccines: Leveraging Biotechnology for Improving Vaccine Development, Stability, and Delivery

“…The conventional vaccine delivery system in poultry involves routes such as oral, nasal spray, wing web injection, and intramuscular and subcutaneous injections [ 160 , 161 ] ( Figure 7 ). The oral route for vaccination is the most common and non-invasive method that stimulates intestinal mucosal response [ 162 ]. Delivering vaccines in the form of oronasal spray or aerosol through the nasal cavity allows for better targeting of the mucosal lining and Harderian gland located in the upper respiratory tract of chickens.…”

Comparative Study of the Immune Response Induced by an Argentinian Classical Strain of IBDV in Two Chicken Breeds

“…Seroneutralization Assay. Te seroneutralization assay was performed as previously described [37]. Briefy, sera were inactivated for 30 min at 56 °C, two-fold serially diluted in culture medium (50% MEM-D, 50% MEM-E, Hepes 1X, pH 7.4), and incubated with 100 TCID 50 of IBDV strain Winterfeld for 1 h at 37 °C in 96-well plates.…”