Study reveals key hurdle for campylobacter vaccine effort

CHICKENS: Immune response does not develop fast enough to fight off bug

New research has revealed the immune response of farmed chickens does not develop fast enough to fight off campylobacter during their short lifespan.

According to Liverpool University, who undertook the study, the findings have important implications in the challenge towards developing a poultry vaccine for the bug, which is the UK’s leading cause of food poisoning.

As both a public health and animal welfare issue, finding a way to control campylobacter infection is a priority for the poultry industry, they said.

There are no commercial vaccines and their development is hampered by poor understanding of the immunobiology of the infection.

The university’s research looked at functional immunity to campylobacter jejuni in chicken – demonstrating that antibody production plays a role, albeit limited, in the clearance of intestinal infection. However, it fails to clear the bacterium within the lifetime of a commercial broiler chicken, which is typically around six weeks of age, the researchers said.

Professor Paul Wigley, from the university’s Institute of Infection and Global Health, said: “Our findings suggest that any campylobacter vaccine relying solely on an antibody response is unlikely to be effective in broiler chickens.”

His team carried out the study by chemically inhibiting the production of antibody-producing white blood cells (B lymphocytes) in broiler chicks, before introducing C.jejuni infection at the age of three weeks.

They then monitored bacteria levels in the guts of the chickens for the next nine weeks.

They found that an antibody associated drop in bacteria levels only became apparent after seven weeks and suggest the adaptive immune response in the gut only begins to mature at six weeks of age.

Professor Wigley added: “It’s likely to be very challenging to produce a protective immune response in broiler chickens before slaughter age, which is around six weeks of age.”

Approximately four in five cases of campylobacter infection in the UK result from contaminated poultry – either through consumption of undercooked meat or through cross contamination in the kitchen.

“It’s likely to be very challenging to produce a protective immune response in broiler chickens. PROFESSOR WIGLEY

As both a public health and animal welfare issue, finding a way to control campylobacter infection is a priority for the poultry industry.