In a world-first, researchers at the Kirby Institute UNSW Sydney, in collaboration with Cornell University in the USA have been able to label and track the immune cells that fight viruses in the body, called CD8+T cells, unlocking the potential to predict how individuals might respond to infection and ultimately enable more targeted treatment.
The discovery was made by genetically altering a mouse to allow for the labelling and tracking of cells throughout its lifetime. Professor Miles Davenport, head of the Kirby Institute’s Infection Analytics Program, was co-author on the study. “We have worked for a number of years to understand the unique properties of T cells in neonatal mice, but this development allowed us to label cells made in the neonatal period, and track them for life”, says Professor Davenport. “It showed that not only did they persist, but that they maintained their unique properties, and played a distinct role as ‘early responders’ to infection in the adult”.
The study, published in Cell on 14 June, shows that ‘neonatal cells’ – produced soon after birth – have a unique behaviour, responding more quickly to infection. These cells survive into adulthood, and continue to maintain their unique behaviour, acting as first responders to infections invading the body. The special behaviour of neonatal cells is encoded by epigenetic changes and seems intrinsic to the cells produced in this period of life.
It is known that individual CD8+ T cells can behave differently during infection, some producing more ‘effector’ cells to fight the virus, and others producing more ‘memory’ cells for later infection, although this is usually thought to be due to random processes. This work shows for the first time that the developmental origin of cells can bias them towards one fate or another. This has potential implications for cell replacement after bone marrow transplantation or HIV depletion, where the neonatal-derived cells may be lost.
Being able to track these cells throughout a lifetime opens the door to better understanding immune development, and how developmental history may shape our responses to infection.
Read the journal article here: https://doi.org/10.1016/j.cell.2018.05.029