AMES - A special set of sugars found on some disease-causing pathogens helps those pathogens fight the body's natural defenses as well as vaccines, say two Iowa State University researchers.
This discovery may be a first step in understanding a disease family that includes tuberculosis for which there are currently no good vaccines or cures.
Nicola Pohl, professor of chemistry, and Christine Petersen, assistant professor of veterinary pathology, discovered that a natural coating of sugar interacts with the body's defense cells to dampen its own immune response.
The findings are published in the current online issue of the Journal of the American Chemical Society.
Pohl and Petersen began studying persistent pathogens such as tuberculosis and the parasite Leishmania five years ago when they noticed that some types of the parasite can make people sick, while others do not.
"One of the things I was curious about was that pathogenic strains of Leishmania have a different sugar coating on them than nonpathogenic strains," Pohl said.
"We asked the question 'Is it possible that just the sugar coating is enough to make something pathogenic or nonpathogenic?'" she said.
Leishmania-associated diseases are not usually found in the United States, but have been observed in soldiers returning from the Middle East. The diseases can cause unsightly sores, and can last a period of months, according to Pohl.
The diseases are often fatal to dogs in the United States.
"The problem is, in places like Bangladesh, where people are in a nutritionally compromised state, peoples' immune systems aren't strong enough, and the disease can be fatal," said Pohl.
Normally, when a disease-causing agent enters the body, cells called macrophages engulf and start to destroy the agent.
Leishmania-type diseases are resistant to this process.
To test the theory on the resistance effect
|Contact: Nicola Pohl|
Iowa State University