Poultry is considered as an important reservoir of Campylobacter and as such various strategies have been explored to control Campylobacter in chickens albeit with little success. Vaccination is considered a promising approach however there are currently no effective vaccines available for the prevention of C. jejuni infections in poultry.
In this study, we constructed and evaluated the effectiveness of a recombinant adenoviral vector based vaccine with C.jejuni flagellin gene (AdX3-flaA) in broiler chickens.
The C.jejuni antigenic gene flaA was amplified from C.jejuni ATCC 43434 by polymerase chain reaction (PCR) and then cloned into an Adenoviral Expression vector system to obtain AdX3-flaA. Recombinant virus was propagated and expressed in HEK293 cells. Gene and protein expression assessed by reverse transcriptase PCR, immunofluorescence and western blot. The AdX3-flaA vaccine was used to immunise broiler chickens at 7 days old and antibody levels measured by Enzyme Linked Immunosorbent Assay (ELISA). Chickens were challenged by oral gavage with chicken isolated wild type C.jejuni at 28 days of age.
The serum IgG and mucosa IgA levels detected in vaccinated chickens was not significantly different to the non-vaccinated chickens. Protection experiment showed that immunisation of chickens with AdX3-flaA led to a reduction in the level of colonisation of the chicken caecum with wild type heterologous chicken C.jejuni strain. The clearance of C.jejuni from the faeces was significantly higher in vaccinated group than non-vaccinated group and C.jejuni could not be detected in the faeces of some of the vaccinated chickens by day 21.