Scientists from the School of Medicine, Trinity College Dublin at the National Children’s Research Centre (NCRC) have identified a class of “danger signals” that are highly efficient at triggering an immune response in infants. The findings have just been published in the prestigious Journal of Immunology.
Infection remains the most common cause of mortality in early life. Vaccination is by far the most effective intervention at preventing infectious disease, however, new-born babies do not respond optimally to most vaccines due to their immature immune system.
For this reason immunisations are scheduled over the first 13 months of life to coincide with the maturation of the infants’ immune system. This leaves a window of vulnerability where new-borns and young infants are susceptible to vaccine-preventable infections, especially for vaccines such as the MMR that are only administered when a child is 1 year old.
CMRF Crumlin, which provides the funding for the National Children’s Research Centre, has committed to further funding into paediatric research in this area to push the boundaries of medical possibilities for sick children.
“Vaccines have two key components, one of which is an ‘adjuvant’,” Dr. Sarah Doyle, from the NCRC, said “These adjuvants are danger signals that instruct the immune system to mount a response to the infection, which in the case of a vaccine is usually an attenuated, inactive form, or fragment of the bacteria or virus.”
The adjuvant is critical not only for triggering the immune system into action, but also in directing the type of response best suited to fight a particular infection.
“Many adjuvants used in vaccines today were developed in adults, however babies and children are not simply little adults, and because of this, a child’s immune system responds differently than an adult’s immune system does” said lead author Dr. Kiva Brennan.
Key to improving vaccine efficacy is the design of adjuvants that specifically target the neonatal immune response into action.
Formation of the microbiome is a critical step in a baby’s development, where ‘good’ bacteria in the gut and on the skin establish and start functioning. It is thought that new-borns do not mount strong immune responses to allow for colonisation by these commensal or ‘good’ bacteria. Viruses, however, have no beneficial function in new-borns, therefore, the team suspected that new-borns may retain a more robust immune response to viruses and began to explore this theory.
The research found that a class of danger signals that activate the cytosolic nucleic acid sensors can drive a very strong immune response in neonates. Commenting on the significance of the research, senior author Dr. Sarah Doyle said.