15 Feb 2022
Researchers identify specific cells important for fighting infection and for long-term protection against influenza infection.
Paul Imrie
Job Title
Scientists at the The Pirbright Institute have identified specific cells in the pig’s immune response that could be important in long-term protection against influenza infection.
Pirbright researchers investigating the animal’s immune response to flu hope the findings will shed more light on the human response – and help in the future development of vaccines.
Pigs are natural hosts for influenza and, like humans, they can be infected by circulating strains. Influenza viruses that infect pigs and humans are different, but some may have the potential to spread between both species, making them important zoonotic viruses.
Scientists have been examining the adaptive immune response, particularly of the CD8 T cell response. CD8 T cells in the immune system specifically target host cells infected with viruses, killing them, and are important in a host’s immune response to disease.
In a first-of-its-kind study in Mucosal Immunology, four different types of CD8 T cells have been identified: naive, central memory, effector memory and differentiated effector porcine CD8 T cells.
Their results showed pig immune response differs from that seen in small animal models for natural hosts of influenza, such as mice or ferrets.
The Pirbright team has revealed both the location of CD8 T cells in different pig tissues and how they behave in response to infection. It was previously thought the number of T cells in the lungs declines rapidly after infection, but the research shows this is not the case – suggesting longer-lasting protection against future infection.
The team also explored how CD8 T cells react in response to infection, with gene expression found to be linked to the production of cytokines. Respiratory immunisation response was also explored.
Elma Tchilian, head of the mucosal immunology group at Pirbright, said: “These findings may prove to be crucial for the design of future vaccines against respiratory diseases.
“Tissue resident memory cells are important in respiratory diseases such as influenza and COVID-19, and identifying in detail where they are located in a relevant animal model is important for our understanding of disease in pigs.
“This knowledge is also highly relevant to human disease. For the first time, we describe the distribution of cells involved in the immune response and their activity over the course of natural infection or vaccination, and these are important knowledge gaps to fill.”
The research was supported by UK Research and Innovation Biotechnology and Biological Sciences Research Council, the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences, the Townsend-Jeantet Prize Charitable Trust and a Medical Research Council grant.
