Effect of Different Routes of Inoculation on Plant-Derived VP2 Immunogenicity and Ability to Confer Protection Against Infectious Bursal Disease

LUCERO, MAR?A SOLEDAD; EVANGELINA GOMEZ; RICHETTA MATÍAS; CHIMENO ZOTH SILVINA; CARBALLEDA JUAN MANUEL; GRAVISACO MARIA JOSE; FERNANDO DELGADO; BERINSTEIN ANALIA

Journal of Virology & Antiviral Research

SciTechnol

Lugar: Bethesda; Año: 2016 vol. 05

nfectious Bursal Disease Virus (IBDV) is the etiological agentof an immunosuppressive and highly contagious disease thataffects young birds causing important economic losses in thepoultry industry. The structural protein VP2 has been used forthe development of subunit vaccines in a variety of heterologousplatforms. We have previously demonstrated that plant-derivedVP2 (pVP2) is able to elicit a neutralizing antibody response inchickens when administered intramuscularly (i.m.) in a prime/boostscheme. However, administration via injection is impractical andcarries the risk of needle stick injury or pain. Mucosal vaccinationis noninvasive and has several advantages over traditionalsystemic vaccines. Taking this into account and the fact thatnatural infections with IBDV occur by the oral route, we decidedto investigate whether pVP2 was also immunogenic when givenintranasally (i.n.) or orally to chickens. In addition, we evaluated ifintramuscular vaccination with VP2 plant extract in a more welfarefriendly scheme with less injections and without adjuvant was ableto elicit a protective immune response against IBDV as previouslyseen. We determined that animals inoculated i.m., but not i.n.,with the experimental vaccine developed high titres of specifcantibodies, with virus neutralizing activity. Also, bursae of animalsvaccinated i.m. with pVP2 presented few infltrating T cells, low viralcharge and normal morphology. However, chickens that received theimmunogen via nasal or oral route were not protected after challenge.Considering the disadvantages of conventional live-attenuated andinactivated vaccines, a plant-based subunit vaccine represents aviable alternative in the veterinary feld. Once again pVP2 has provento be immunogenic when parentally inoculated. However, furtherinvestigations need to be done in order to fnd an alternative route ofadministration which is more practical than the intramuscular injectionand capable of eliciting a mucosal immune response