Dr Francesca Soutter, Postdoctoral Scientist in Vaccine Development, has been awarded a grant by the Houghton Trust (who promote research into poultry diseases) for MHC diversity in commercial layer chickens and the impact on response to primary infection with Eimeria tenella.
Coccidiosis, caused by the protozoan parasite Eimeria, is a common cause of intestinal disease in the chicken. As well as impacting on individual chicken welfare it results in production losses, requiring costly treatments and interventions estimated to cost the global chicken industry around £2 billion yearly. Whilst vaccines against Eimeria exist, they are often cost prohibitive in the production of broiler chickens for meat, resulting in the use of in-feed anticoccidial drugs. Now, with increasing concerns regarding the use of antimicrobial drugs in livestock and the spread of antimicrobial resistance, demand for cost-effective vaccines is greater than ever.
Vaccine development has been somewhat hampered by the variability in response to infection with Eimeria parasites in commercial birds as results of vaccine challenge experiments can be difficult to interpret in these populations. It is likely that chicken immunogenetics, the genes responsible for the immune response generated to the pathogen and to vaccination, are at least partially responsible for this variability.
This study will examine the immune genes of the major histocompability complex (MHC), which are important in how pathogens are recognised by the immune system. Initially three breeds of layer chickens that have been characterised for their response to Eimeria tenella infection will be examined. This will determine the variability in these genes between the different breeds and also assess whether these genes are involved in response to Eimeria infection. A more detailed examination of MHC genes and their impact on Eimeria infection will then be carried out in a single commercial layer breed. A better understanding of MHC genetic diversity within commercial chickens would enable refinement of vaccine challenge studies ensuring more robust studies and potentially reducing the numbers of chickens required. It could also assist with selection of new vaccine targets for commercial chickens, based on the predicted interactions of those targets with immune cells of chickens with known MHC genes.