Novel approaches to identifying key molecules associated with immunity have enabled researchers to identify a chicken immune cell with a critical role in mediating fighting infection. The findings, from the first study of its kind in birds, also highlighted key similarities and differences between mammalian and avian immunity.
A team of researchers led by the Roslin Institute developed methods of distinguishing signature molecules associated with the function of key immune cells known as conventional dendritic cells. Their work will underpin studies of conventional dendritic cells, which play a key role in fighting infection in many species, but are difficult to detect in birds.
In a novel approach, the team developed reagents designed to react with molecules involved in conventional dendritic cell development and function.
They generated an antibody that could be used to detect a key molecule named FLT3 and fluorescently labelled a peptide, a small protein, which could detect a second molecule, XCR1, on the surface of conventional dendritic cells.
By using these markers, researchers were able to distinguish dendritic cells from other cell types, and to discover insights into their function, including details of how they interact with Salmonella bacteria.
The reagents developed for the study will support further research to understand the functions of chicken immune cells, and support development of vaccines against viral and bacterial diseases.
Their study involved chickens which had been genetically modified to enable fluorescent imaging of immune cell activity.
Evolution of mammals and birds
The use of these transgenic chickens enabled the team to make important insights to how the immune system in birds differs from those in mammals, such as mice, in which most previous studies have been carried out.
The study, carried out with the University of Queensland, Australia and the National Avian Research Facility at the Roslin Institute, was supported by Wellcome and BBSRC and published in Immunology.
"This study has developed the tools to unpick the complex story of how the chicken immune system responds to infectious disease and will support future research into producing more effective vaccines," said Dr Adam Balic, with the Roslin Institute. "Our outcome indicates that mammals and birds share some aspects of their defenses against infection, which pre-date the evolutionary split between mammals and birds some 320 million years ago. This suggests the systems they have in common, such as those pinpointed in our research, must be fundamentally important in nature."
The Roslin Institute receives strategic investment funding from the Biotechnology and Biological Sciences Research Council and it is part of the University of Edinburgh's Royal (Dick) School of Veterinary Studies.