December 18, 2013
US researchers develop novel vaccine for infectious bronchitis virus
US POULTRY and the US POULTRY Foundation announced completion of a funded research project on the development of a novel vaccine for infectious bronchitis virus (IBV) conducted at Auburn University, Alabama, USA.
This project is part of the Association''s comprehensive research programme encompassing all phases of poultry and egg production and processing.
Led by Haroldo Toro, a team of researchers developed a novel method for vaccinating chickens against infectious bronchitis virus (IBV). Because IBV varies widely in its makeup, flocks of chickens often have to be vaccinated with multiple serotypes of IBV vaccines. The Auburn team, for the first time, developed technology which induces an immune response against multiple serotypes of IBV without having to use multiple vaccine serotypes. This novel vaccine research has the potential to revolutionise IBV prevention in both the broiler and layer industries.
Infectious bronchitis virus (IBV) is the most common contributor to overall disease losses in the US chicken industry due to increased condemnations at processing plants and declines in egg production. IBV''s unique capability to evolve effectively counteracts extensive vaccination programmes with available serotype-specific vaccines. IBV is covered with spikes, which it uses to attach to chicken cells. The tip of the spike is made of a protein called S1. The makeup of the S1 protein varies with each serotype of IBV. The stalk of the spike is made of a protein called S2, and the structure of the S2 protein is very similar amongst all IBV''s.
The researchers developed a novel recombinant Newcastle Disease virus (NDV) LaSota (rLS) expressing the IBV S2 gene (rLS/IBV.S2). The initial results indicated that chickens primed with this recombinant vaccine and boosted with a commercial attenuated IBV Massachusetts (Mass)-type vaccine were protected against heterologous challenge with an IBV Ark-type virulent strain. In brief, chickens primed ocularly with rLS/IBV.S2 at 4 days of age and boosted with Mass at 18 days of age were completely protected against challenge at 41 days of age with a virulent Ark-type strain. In a second experiment, birds primed at one day of age and boosted at 12 days of age were protected against virulent Ark challenge at 21 days of age. These initial results demonstrate that overexposing the IBV S2 to the chicken immune system by means of a vectored vaccine, followed by boost with whole virus, protects chickens against IBV showing dissimilar S1. It is anticipated that S2 expressed from any vector (HVT, Pox, or other) should provide similar protective results.
The recombinant LaSota strain used herein effectively elicited antibodies against NDV and protected chickens against lethal challenge with virulent NDV (NDV/CA02). This novel vaccine transformative research has the potential to revolutionize IBV prevention and control by replacing a multiplicity of currently existing type-specific IBV vaccines.
US Poultry & Egg Association is the all-feather organisation representing the complete spectrum of today''s poultry industry, whose mission is to progressively serve member companies through research, education, communication, and technical assistance.