Destroying the Power Parasites Have Over the Immune System
Billions of people carry parasites within them as they journey through life. The parasites range in size from single-cell protozoans, such as the malaria parasite, to metres-long tapeworms found in the gut. Those that have captured the interest of Canada Research Chair Professor Timothy Geary are "filarial" parasites, which can grow up to half a metre in length. An example of an infection caused by filarial parasites is elephantiasis, in which infected individuals develop grossly enlarged limbs.
Filarial parasites are a kind of nematode or roundworm. They inhabit certain tissues, such as the skin or lymphatic vessels, of millions of people, somehow escaping immune detection and destruction. Geary studies how they evade detection; he believes that the answer may provide insights into selective immunosuppression - and offer new ways to limit parasitic infections in humans and animals.
The major filarial infections of humans are sensitive to certain kinds of drugs that may act, at least in part, by exposing the parasite to the host's immune responses. Using proteomic and genomic technology, Geary examines how these drugs alter the host-parasite playing field. The tools allow him to identify molecules released by the parasite and study how the molecules affect the ability of host immune cells to "see" and attack the invader.
At the same time, Geary analyzes the molecules that the host releases in its attempt to eliminate the parasite. The balance between the responses of the host and those of the parasite may be at least partly responsible for the pathology caused by the infection. By identifying the relevant molecules, Geary is taking the first step toward understanding how they work and how manipulating them might tilt the balance in favour of the host.