Navigation Links
Humanized mice may provide clues to better prevent and treat typhoid fever
Date:9/22/2010

Better treatments and prevention for typhoid fever may emerge from a laboratory model that has just been developed for the disease. The model is based on transplanting human immune stem cells from umbilical cord blood into mice that are susceptible to infections.

The transplanted cells live alongside the mouse's own immune system. Although mice are normally resistant to the dangerous strain of Salmonella that causes typhoid fever, the bacteria are able to reproduce in the mice that have received transplanted human cells.

Because typhoid fever affects only humans, progress in creating more effective vaccines and medications has been limited, notes Dr. Ferric C. Fang, professor of laboratory medicine and microbiology at the University of Washington (UW) in Seattle and the senior scientist on the project. The new model enables scientists to study innovative approaches against the disease in a living system, before testing them on people.

The "humanized" mouse model for studying Salmonella typhi infections was reported recently in the Proceedings of the National Academy of Sciences. The lead author of the paper is Stephen J. Libby, research associate professor of laboratory medicine.

The World Health Organization estimates that more than 16,000,000 new cases of typhoid fever occur annually. More than 600,000 people die each year from the disease, which is transmitted through contaminated food or water. Making the situation worse, multi-drug resistant strains have emerged. Researchers are looking for new drugs to replace those that are no longer effective.

The current typhoid fever vaccines have protection rates ranging from 60 to 80 percent. The protection conferred by the present inoculation is short-lived, and doesn't have a booster effect, the researchers explained. The oral vaccine spoils easily if storage conditions aren't optimal as is the case in many tropical countries where typhoid fever is common. It also requires multiple doses. Studies in travelers suggest that many fail to take the vaccine properly.

Most of what scientists know about how Salmonella causes disease comes from studying a strain called Salmonella typhimurium, which can infect both mice and humans.

However, Fang noted that Salmonella infections in mice have not been found to correlate well with human typhoid infections.

"The mouse Salmonella infection differs from human typhoid in a number of important respects," he said. Immunity to one strain is fundamentally distinct from immunity to the other. This complicates attempts to construct vaccines based on observations of mice infected with Salmonella typhimurium."

Fang added that Salmonella typhi, the cause of human typhoid fever, is highly adapted to people. It has evolved many ways to evade infection-fighting defenses inside humans. It can also enter and destroy disease-fighting cells. The bacteria induce inflammation where it is in their own self-interest, and suppress it when and where it might be a disadvantage, such as in the intestine. Salmonella has changed over time by acquiring new DNA, such as plasmids and bacteriophages, from other organisms. This borrowed DNA makes it more virulent to humans and other animal hosts.

The host-pathogen interactions in mouse typhoid and human typhoid fever are drastically removed from each other, Fang said.

The researchers demonstrated that human blood-forming cells engrafted into immune-deficient mice allowed the mice to be infected with the organism that causes human typhoid fever, and that the typhoid bacteria appeared to reproduce inside the human cells. The researchers were also able to use this model to look for genetic factors that the typhoid bacteria need to cause severe illness.

Based on their studies, the researchers believe that the new lab mouse model can provide an unprecedented opportunity to gain insights into how the human typhoid fever bacterium, Salmonella typhi, causes serious disease and to devise better strategies for the prevention of typhoid fever. Their research also demonstrates how mice engrafted with human stem cells can allow scientists to better understand human infections.


'/>"/>

Contact: Leila Gray
leilag@u.washington.edu
206-685-0381
University of Washington
Source:Eurekalert  

Related biology news :

1. Rotating high-pressure sodium lamps provide flowering plants for spring markets
2. New insights provide promise for development of tools to protect damaged tissues
3. Hair provides proof of the link between chronic stress and heart attack
4. LSUHSC pediatric weight expert provides obesity trinity answers
5. Special edition journal provides new perspectives and guidance for managing white pine blister rust
6. Huntingtons disease discovery provides new hope for treatment
7. Mother Nature to provide an environmentally friendly method for reducing mosquitoes
8. Aware Biometrics Software Provided for Large Federal Agencys PIV Credentialing System
9. Flemish researchers provide the first experimental evidence of dynamic allostery in protein regulation
10. World-renowned authorities provide current perspectives on Darwins theory of evolution
11. De La Rue Provides Second-Generation ePassport for Malta
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Humanized mice may provide clues to better prevent and treat typhoid fever
(Date:3/11/2016)... , March 11, 2016 ... new market research report "Image Recognition Market by Technology ... (Marketing and Advertising), by Deployment Type (On-Premises and Cloud), ... To 2022", published by MarketsandMarkets, the global market is ... to USD 29.98 Billion by 2020, at a CAGR ...
(Date:3/10/2016)... 2016   Unisys Corporation (NYSE: UIS ) ... (CBP) is testing its biometric identity solution at the Otay ... to help identify certain non-U.S. citizens leaving the country. ... to help determine the efficiency and accuracy of using biometric ... will run until May 2016. --> the ...
(Date:3/9/2016)... HAMBURG, Germany , March 9, 2016 ... African country,s government identified that more than 23,000 public ... name or had been receiving their salary unlawfully.    ... West African country,s government identified that more than 23,000 ... recorded name or had been receiving their salary unlawfully. ...
Breaking Biology News(10 mins):
(Date:5/27/2016)... At present, the Biotech sphere is in a ... volatility is what makes this industry interesting to consider. Here ... (NASDAQ: SNTA ), CTI BioPharma Corp. (NASDAQ: ... and Heat Biologics Inc. (NASDAQ: HTBX ). Sign ... these stocks at: http://www.activewallst.com/register/ ...
(Date:5/26/2016)... , May 26, 2016 Despite ... see value in this space. Today,s pre-market research on ActiveWallSt.com ... Radius Health Inc. (NASDAQ: RDUS ), Cerus Corp. ... ARWR ), and Five Prime Therapeutics Inc. (NASDAQ: ... technical briefings at: http://www.activewallst.com/ ...
(Date:5/25/2016)... ... May 25, 2016 , ... Lajollacooks4u has become a rising hotspot for ... one of its top attractions. Fortune 500 companies, such as Illumina, Hewlett-Packard, Qualcomm ... and intimate team-building experience. , Each event kicks off with an olive oil and ...
(Date:5/25/2016)... (PRWEB) , ... May 25, 2016 , ... ... for information (RFI) issued by the Office of the National Coordinator for Health ... experience, and determines if clinically relevant data were available when and where it ...
Breaking Biology Technology: