Submitted to: Vaccine
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/20/2012
Publication Date: 3/3/2012
Citation: Sylte, M.J., Suarez, D.L. 2012. Vaccination and acute phase mediator production in chickens challenged with low pathogenic avian influenza virus; novel markers for vaccine efficacy. Vaccine. 30(2012):3097–3105. Interpretive Summary: Vaccination is sometimes used for the control of avian influenza viruses in poultry. Typically vaccines are tested in the laboratory to show a decrease in illness in birds as part of the licensing process. However, for low pathogenic avian influenza, it is common that no clinical disease is observed in birds infected in the laboratory because disease is often associated with dual infection with other viruses or bacteria. This report describes the detection of different blood markers, called acute phase proteins, that increase as part of the inflammation process often associated with viral infections. Three different blood markers were evaluated and all three showed differences in vaccinated and non-vaccinated birds showing it could be used to show protection by the vaccine. This approach may help vaccine producers demonstrate protection to aid in their vaccines getting licensed for field use.
Technical Abstract: Methods to determine vaccine efficacy of low pathogenic avian influenza (LPAI) isolates are limited in poultry because experimental infections with LPAI virus in specific pathogen free chickens rarely causes clinical disease. The most commonly used method to compare LPAI vaccine efficacy is to quantify viral shedding after challenge, but it is time and labor intensive. Therefore, we sought alternative methods to demonstrate vaccine efficacy, and examined whether vaccination of chickens affected the production of acute phase mediators in serum (e.g., alpha-1 acid glycoprotein, ovotransferrin and prostaglandin E2) following challenge with homologous (A/Chicken/Hidalgo/232/94 H5N2) or heterologous (A/Chicken/167280-4/02 H5N3) LPAI isolates. Vaccination significantly reduced oropharyngeal viral shedding, and serum concentration of acute phase mediators, regardless of whether homologous or heterologous challenge viruses were used. Examining the expression of acute phase mediators post-challenge may serve as additional markers to determine LPAI vaccine efficacy in chickens.