Featured Research

from universities, journals, and other organizations

Friendly Bacteria Block HIV Infection

Date:
May 27, 2004
Source:
American Society For Microbiology
Summary:
Certain strains of bacteria that occur naturally in the human mouth can snare the HIV virus and even cells it has infected, according to researchers at the University of Illinois at Chicago College of Dentistry.

NEW ORLEANS – May 25, 2004 -- Certain strains of bacteria that occur naturally in the human mouth can snare the HIV virus and even cells it has infected, according to researchers at the University of Illinois at Chicago College of Dentistry. They report their findings today at the 104th General Meeting of the American Society for Microbiology.

In laboratory tests, the researchers found that the bacteria latched onto the sugar coating on the envelope that encases the virus particle and blocked infection. The bacteria also bound the sugar coating on immune cells, causing them to clump – a feature that could render those harboring HIV incapable of infecting other cells.

"This discovery opens up a possible means of preventing the transmission of HIV from mother to infant through breast feeding," says Lin Tao, associate professor of oral biology at the UIC College of Dentistry, who directed the study in collaboration with colleagues at UIC and Rush University Medical School. Worldwide, mother-child transmission of HIV results in 800,000 new infections each year.

Tao and his colleagues screened hundreds of oral bacteria taken from the saliva of healthy volunteers before identifying six Lactobacillus strains that produced proteins capable of binding the particular type of sugar found on the HIV envelope, called mannose. The binding of the sugar normally enables the bacteria to stick to the mucosal lining of the mouth and digestive tract, forming colonization.

Further screening identified two strains capable of trapping live HIV viruses by binding with glycoprotein receptors, called gp120, in their viral envelope composed of protein spikes and a sugar "dome" rich in the mannose sugar. The sugar "dome" prevents HIV from being recognized by the human immune response, but it is the target of these lactobacilli. Each HIV virus has about 72 such glycoprotein receptors.

"The two strains were found to bind with several varieties of HIV, the related simian immunodeficiency virus, and immune cells that HIV targets for infection, which are also covered with mannose. Further analysis showed that the bacteria inhibited HIV infection of immune cells in the laboratory," says Tao.

One strain secreted abundant mannose-binding protein particles into its surroundings, neutralizing HIV by binding to its sugar coating. The other Lactobacillus strain also neutralized HIV particles but required direct contact with the virus because its mannose-binding proteins reside on its surface. That requirement made this strain less effective in tackling HIV particles, but it proved remarkably efficient at binding with immune cells, whose surfaces, like HIV, also contain glycoprotein receptors. The researchers observed that immune cells trapped by lactobacilli formed a clump. That configuration would be expected to immobilize any immune cells harboring HIV and prevent them from infecting other cells.

While HIV exist as many subtypes because of frequent mutations, posing a challenge for vaccines, the sugar coating of the virus remains largely the same, presenting a ready target for lactobacilli to attack no matter whether the virus particle itself is genetically altered.

"While studies have been done so far only in the laboratory, we believe this work opens up new possibilities for preventing the transmission of HIV through mothers' milk," says Tao. "Unlike standard retroviral drugs, which are too toxic for newborns, lactobacilli are 'friendly' bacteria already inhabiting the human digestive tract and milk products, and so should pose no danger to infants."


Story Source:

The above story is based on materials provided by American Society For Microbiology. Note: Materials may be edited for content and length.


Cite This Page:

American Society For Microbiology. "Friendly Bacteria Block HIV Infection." ScienceDaily. ScienceDaily, 27 May 2004. <www.sciencedaily.com/releases/2004/05/040526071039.htm>.
American Society For Microbiology. (2004, May 27). Friendly Bacteria Block HIV Infection. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2004/05/040526071039.htm
American Society For Microbiology. "Friendly Bacteria Block HIV Infection." ScienceDaily. www.sciencedaily.com/releases/2004/05/040526071039.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
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:
from the past week

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