Featured Research

from universities, journals, and other organizations

Progress in understanding immune response in severe schistosomiasis

Date:
April 16, 2014
Source:
Tufts University
Summary:
A mechanism that may help explain the severe forms of schistosomiasis, or snail fever, has been discovered by researchers. Schistosomiasis is one of the most prevalent parasitic diseases in the world. The study in mice may also offer targets for intervention and amelioration of the disease. Although schistosomiasis is not contracted in the United States or Europe, the World Health Organization reports that this neglected tropical disease is endemic primarily in Africa, but is also found in South America, the Middle East, and Asia.

Schistosoma in its larval stage of life.
Credit: Centers for Disease Control and Prevention (CDC) (Dr. Sulzer)

Researchers at the Sackler School of Graduate Biomedical Sciences at Tufts and Tufts University School of Medicine (TUSM) have uncovered a mechanism that may help explain the severe forms of schistosomiasis, or snail fever, which is caused by schistosome worms and is one of the most prevalent parasitic diseases in the world. The study in mice, published online in The Journal of Immunology, may also offer targets for intervention and amelioration of the disease.

Related Articles


Schistosomiasis makes some people very sick whereas others tolerate it relatively well, and no one knows precisely why. To answer this question, Miguel Stadecker, M.D., Ph.D., professor in the Department of Integrative Physiology & Pathobiology at Tufts University School of Medicine, uses mouse strains that similarly develop severe or mild disease. He and Holly E. Ponichtera, graduate student in immunology at the Sackler School, discovered that an innate cell receptor called CD209a is linked to the development of T helper (Th) 17 cells, which can cause marked inflammation.

Th17 cells are part of the adaptive immune response, fighting certain disease-causing bacteria and fungi, but they are also implicated in the pathogenesis of autoimmune diseases. The Stadecker lab had previously reported that blocking Th17 cell function limits severe schistosomiasis.

"This is important," says Ponichtera, "because CD209a is a mouse equivalent of a molecule that in humans is called DC-SIGN, a lectin receptor on dendritic cells that senses a variety of pathogens, including the virus that causes AIDS. Regulating this molecule may prevent excessive unwanted inflammation, such as that seen in severe schistosomiasis."

Stadecker has been studying this disease since the 1980s, analyzing the host's immune response to the parasite eggs. His earlier work showed the importance of Th17 cells in understanding schistosomiasis. This type of T cell was present in larger quantities in mice with severe disease. He surmised that the Th17 cells also caused the severe inflammatory response seen in some patients.

In 2013, the laboratory's discovery of the role of Th17 cells was confirmed in the field when an international team of researchers tested blood samples from children in Senegal who were infected with schistosomiasis. The samples confirmed that Th17 cells were increased in patients with measurable pathology whereas, in infected individuals with no overt symptoms, the Th17 cells were offset by T regulatory cells that inhibit inflammation.

"We don't yet understand why mice that develop severe inflammation express about 20 times higher levels of CD209a than mice that do not develop severe disease, and we don't yet know about the role of DC-SIGN in human schistosomiasis. However, these cumulative results move us a bit closer to understanding why the disease manifestations can range from very few symptoms to death. Our studies might also have implications for diseases caused by other pathogenic helminths," said Stadecker, also a member of the also a member of the immunology program faculty at the Sackler School.

For more than 249 million people in the world, water is both a precious resource and a vehicle of disease. Fresh-water snails living in certain tropical regions of the world release the larval forms of the schistosome parasite, which penetrate the skin, migrate through the body, and develop into adults that lay eggs that cause the disease. While some people experience chronic infection with mild symptoms, about 10%, will develop severe inflammatory disease that can affect the gastrointestinal, urinary, and nervous systems, in some cases causing cancer or leading to death.

Although schistosomiasis is not contracted in the United States or Europe, the World Health Organization reports that this neglected tropical disease is endemic primarily in Africa, but is also found in South America, the Middle East, and Asia. Population migration has introduced schistosomiasis to new areas. Although effective drug treatment is available, re-infection is pervasive, and a vaccine is not available.


Story Source:

The above story is based on materials provided by Tufts University. The original article was written by Siobhan Gallagher. Note: Materials may be edited for content and length.


Journal Reference:

  1. H. E. Ponichtera, M. G. Shainheit, B. C. Liu, R. Raychowdhury, B. M. Larkin, J. M. Russo, D. B. Salantes, C.-Q. Lai, L. D. Parnell, T. J. Yun, C. Cheong, S. C. Bunnell, N. Hacohen, M. J. Stadecker. CD209a Expression on Dendritic Cells Is Critical for the Development of Pathogenic Th17 Cell Responses in Murine Schistosomiasis. The Journal of Immunology, 2014; DOI: 10.4049/jimmunol.1400121

Cite This Page:

Tufts University. "Progress in understanding immune response in severe schistosomiasis." ScienceDaily. ScienceDaily, 16 April 2014. <www.sciencedaily.com/releases/2014/04/140416101341.htm>.
Tufts University. (2014, April 16). Progress in understanding immune response in severe schistosomiasis. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2014/04/140416101341.htm
Tufts University. "Progress in understanding immune response in severe schistosomiasis." ScienceDaily. www.sciencedaily.com/releases/2014/04/140416101341.htm (accessed October 23, 2014).

Share This



More Health & Medicine News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com
Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Despite Rising Death Toll, Many Survive Ebola

Despite Rising Death Toll, Many Survive Ebola

AP (Oct. 23, 2014) The family of a Dallas nurse infected with Ebola in the US says doctors can no longer detect the virus in her. Despite the mounting death toll in West Africa, there are survivors there too. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins