Animal rights activists often argue that animal models are irrelevant for human medicine, because they are ‘so different’ from us. But in fact some basics are shared across wildly distant species – something that the Nobel Committee acknowledged last year when they gave the Prize for Medicine and Physiology to Bruce Beutler and Jules Hoffmann for discovering the ‘early warning’ signals that set off immune responses in flies, mice and humans.
On Jan. 25 both Beutler, who works at the University of Texas in Dallas, and Hoffmann of the University of Strabourg, France, were at the University of California, Davis talking to a packed house about their work. Joining them on stage was UC Davis plant pathologist Pam Ronald, who studies rice, and Luke O’Neill of Trinity College Dublin, Ireland, who talked about human medicine.
(Watch the presentations here: http://ccm.ucdavis.edu/immunity.html)
Work in these very different organisms can give insights that advances human medicine. From the basic discoveries in mice, flies and even rice could come new drugs and new approaches to treat heart disease, rheumatoid arthritis, inflammatory bowel disease and other conditions.
Our immune system has two lines of defense. The innate immune system reacts first, attacking invading microbes and triggering inflammation. If that response fails, the adaptive immune system fights back with antibodies and specialized killer cells. Afterward, the adaptive immune system retains a memory that allows a more rapid and powerful response if the same virus, bacterium or parasite comes back.
Only animals with backbones, from fish to humans, have an adaptive immune system. But all animals, including insects, as well as plants, have innate immune systems.
In the 1990s, Ronald (working with rice), Hoffmann (with Drosophila flies) and Beutler (with mice) identified genes for immune receptors that triggered innate immunity in the rice, flies and mice, and found that the genes were remarkably similar despite hundreds of millions of years of evolution.
From this common trigger, plants, insects and animals develop different types of response to invaders.
Activation of the immune system is not always a good thing. It can lead to allergy, inflammatory diseases such as rheumatoid arthritis or autoimmunity, when the body starts attacking its own tissues.
In his talk, for example, Beutler described how his team, working with mice, has isolated genes related to inflammatory bowel disease, while O’Neill talked about the possibility of being able to develop drugs to treat a wide range of diseases linked to inflammation.
The symposium is an annual event sponsored by a fund created by AIDS pioneer and UC Davis professor emeritus Murray Gardner, who previewed in an interview for Sacramento Public Radio Jan. 24 [http://www.capradio.org/168919] At the beginning of the AIDS epidemic in the 1980s, Gardner helped discover viruses similar to HIV in monkeys and cats – animal models that have been of vital importance in discovering drugs to treat and prevent HIV/AIDS.
– Andy Fell