During an immune response to an infection, immune T cells that
recognize the invading microbe increase in number through cell division,
and become armed to fight the infection. These 'armies' of T cells will
stop expanding at a later point, and are cleared by the death of most
of the cells, leaving only a few 'sentinels' called memory cells that
provide long lasting immunity.
Australian and Irish researchers have gained previously unachievable
insights into how the size of our immune response is controlled, by
developing new imaging and computational biology approaches to follow
the behavior of hundreds of cells.
‘In response to an infection, immune T cells develop in 'families' that are programmed to divide and die at different times after the infection is detected.’
The research team discovered that in response to an infection, immune T
cells develop in 'families' that are programmed to divide and die at
different times after the infection is detected. This new understanding
of how the immune response is controlled may underpin future
improvements in vaccination or the treatment of autoimmune diseases.
Dr. Julia Marchingo, Professor Phil Hodgkin and colleagues at the
Walter and Eliza Hall Institute worked with Professor Ken Duffy and Mr.
Giulio Prevedello from Maynooth University, Ireland, to develop a new
way to track immune T cells as they divide and increase in number during
an immune response. Their research was published in the journal Nature Communications
The new imaging and computational biology techniques revealed that
'families' of immune cells develop during an immune response, said Dr.
Marchingo, who is now a postdoctoral researcher at the University of
"Like families of people, these families of T cells vary in their
characteristics," she said. "In the case of T cell families, the
variability we detected was in how many times the cells would divide,
and at what point in the immune response the cells would die. We were
surprised by how consistent these were within each family of cells - as
if the related cells had inherited a set of instructions specifying how
they should behave," Dr. Marchingo said.
Professor Duffy said the team's discovery of how immune cells respond
to infection was driven by an entirely new approach to analyzing the
immune response. "In the past we had to track immune cells using
microscopy, watching individual cells over days to see whether they were
dividing or dying," he said. "This was incredibly time consuming and
limited our ability to understand the intricacies of the immune
response. By combining laboratory techniques with mathematical analyses
we could follow hundreds of T cell families, and realized that their
behavior was influenced by which family they belonged to."
Professor Hodgkin said the research team's discovery was an important
advance in understanding how immune responses are controlled. "As well
as providing new insights into how we protect ourselves from infection,
this research could explain some of the problems that contribute to
autoimmune disorders, when the immune system mistakenly attacks the
body, as well as underpinning advances in vaccination technology," he