The role of rare innate immune cells in Type 2 immune activation against parasitic helminths
The latest Paper of the Month in Parasitology is The role of rare innate immune cells in Type 2 immune activation against parasitic helminths by Dr. Elia Tait Wojno
Parasitic helminths (worms) can live in their hosts for decades. This incredible feat is largely due to the sophisticated mechanisms that they have evolved to subvert the mammalian immune system. Given that parasitic worms have developed such complex mechanisms to survive in their host, how then does the immune system effectively combat this foe?
Decades of study have revealed that a highly specialized network of immune and epithelial cells must cooperate to expel the parasitic burden. The immune system consists of two lines of defense. The first line is the innate immune system, which consists of a range of cells that respond to distress signals from worm-damaged tissues. These cells activate the second line of defense, the adaptive immune system, which specifically recognizes particular pathogens. Together, these two arms of the immune system promote the development of anti-worm mechanisms that facilitate parasite expulsion.
For many years, research had focused on the adaptive immune system and its role in eliminating parasitic worms. However, more recently, it has become clear that the cells of the innate immune system are equally important for fighting worms. Notably, some of these innate immune cells exist in such small numbers that they can be hard to find, and thus hard to study. However, despite their rarity, these cells are potent activators of anti-worm responses, and are highly adapted to this role. They exist at sites in the body where worm damage is most likely to occur. They rapidly and robustly respond to damage signals from affected tissues, producing large quantities of inflammatory mediators that can activate adaptive immune cells or directly act back on damaged tissues to elicit mechanisms that help to expel worms. Some of these cells carry genetic modifications that allow rapid and robust gene expression changes in response to a range of incoming signals from surrounding cells. Current research is focused on better understanding the mechanisms and pathways that allow these cells to respond so effectively and potently.
We now appreciate that rare innate immune cells exist not only to activate adaptive immune mechanisms, but also to directly facilitate worm expulsion. Our review highlights the range of functions that innate immune cells can have, and how these cells are specifically adapted for their roles. The next step is to continue the journey to increase our understanding of how rare innate immune cells function, in order to inform the development of more effective therapeutics to combat worm infection.
Read the full article “The role of rare innate immune cells in Type 2 immune activation against parasitic helminths” in full for free until 31st October 2017.