STANFORD, Calif. - The tiny fruit fly has a lot to teach humans. Researchers at the Stanford University School of Medicine have found for the first time that flies' primitive immune systems may develop long-term protection from infection, an ability previously thought impossible for insects.
The findings could have implications for new ways of developing human vaccines, especially for people with compromised immune systems.
The evidence that a fruit fly's immune response can adapt to - or retain memory of - an earlier infection contradicts the long-held dogma that immune memory cannot exist in invertebrates such as insects. Such memory of a specific pathogen, known as adaptation, is supposed to be a hallmark of the higher-level immune system response of humans and other vertebrates.
The Stanford work raises the possibility that humans could make use of this rudimentary immune response if their higher-level system is crippled. "It's a springboard to looking at the immune system in a whole new way," said David Schneider, PhD, assistant professor of microbiology and immunology and senior author of the study, which will be published in the March 9 issue of Public Library of Science-Pathogens.
One of the two arms of the immune response in higher organisms is similar to that of flies. This arm is known as innate immunity, and it is thought to be a primitive first-line, nonspecific response to a pathogen "invader." The other arm found in higher organisms is adaptive immunity, which has a memory that retains an internal record of contact with an invader and - employing T and B cells - springs into action once it encounters the same invader again. This adaptive immunity explains why a vaccine provides protection.
"AIDS patients are like fruit flies in the sense that they don't have properly functioning T cells," said Schneider. "If there is anything we could do to make their remaining innate immunity better through adaptat
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Contact: Mitzi Baker
mabaker@stanford.edu
650-725-2106
Stanford University Medical Center
8-Mar-2007