Real-time RT-PCR analysis of two epitope regions encoded by the VP2 gene of infectious bursal disease viruses
Infectious bursal disease virus (IBDV) causes an immunosuppressive disease in chickens and leads to severe economic losses in the poultry industry. Vaccination may not be effective if there is exposure of the vaccinated flock to a different antigenic subtype, which reinforces the importance of identification of new IBDV variants. The virus outer capsid is constituted of VP2, in which the major neutralizing epitopes are located. Forty-eight bursa samples collected from IBDV infected commercial broiler flocks in the US were analyzed by real-time RT-PCR using probes designed for two epitope regions of VP2 denominated minor peak 1 and peak B. It was observed that 23, 48 and 44 samples tested with the minor peak probes Del-E, STC and F15, respectively, had a lower melting temperature (Tm) than expected. Furthermore, 44, 41 and 48 samples tested with the Del-E, STC and F15 peak B probes respectively, had a lower Tm compared to the control, which indicates the presence of one or more nucleotide mutations in the samples. This fact was confirmed by nucleotide sequencing which also demonstrated that most mutations resulted in amino acid substitutions. Real-time RT-PCR can be a useful tool to assist in the development of more effective vaccination strategies. An analysis of immunosuppression induced by infectious bursal disease virus (IBDV) on Campylobacter infection was conducted. IBDV-induced immunosuppression increased C. jejuni colonization and shedding, emphasizing the need for further investigation into the effect of immunosuppression on the pre-harvest incidence of food-borne pathogens.
School:The Ohio State University
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:infectious bursal disease virus real time rt pcr identification
Date of Publication:01/01/2005