Researchers at the University of Liège (Belgium) have uncovered a previously unknown mechanism that regulates the immune response against parasites. During a parasitic infection, specific immune cells, known as virtual memory T cells (TVM), become activated and express a surface molecule called CD22, which prevents an excessive immune reaction. This discovery could help in better-controlling inflammation and improving immune responses to infections.
Nearly a quarter of the world’s population is infected by helminths, parasitic worms that establish themselves in the intestine for extended periods. In response to these invaders, the immune system deploys complex defence strategies. A recent study, conducted by a team of researchers at the University of Liège, has revealed a previously unsuspected mechanism that regulates the activation of certain immune cells: CD8+ virtual memory T cells (TVM).
A surprising role for CD22 in T Cell regulation
The researchers found that during helminth infections, a key immune molecule, interleukin-4 (IL-4), strongly stimulates TVM cells, causing their proliferation in the spleen and lymph nodes. TVM cells are immune cells capable of reacting rapidly to viral infections. In a previous study published in 2018, the research team demonstrated that IL-4 stimulation of TVM cells enhances viral infection control during co-infections with helminths and viruses. However, this intense stimulation of TVM cells during parasitic infection does not appear to play a role in controlling the parasite itself, which intrigued the researchers.
“What is surprising is that this activation of TVM cells is accompanied by the expression of a receptor called