Medindia

X

HIV Hideout in Humans Discovered

by Rajshri on  May 15, 2008 at 3:50 PM AIDS/HIV News   - G J E 4
HIV Hideout in Humans Discovered
HIV hides in a type of reservoir cells, called follicular dendritic cells (FDCs) when drug treatment is initiated, researchers at Brigham Young University and Johns Hopkins School of Medicine have found.
Advertisement

The researchers found that FDCs, which are located throughout the body in specialized sites known as lymphoid tissue, act as bank vaults storing material necessary to maintain the immune system's armies of antibodies.

Advertisement
If the ranks of a particular antibody dwindle, FDCs release proteins that trigger an immune response boosting levels of specific antibodies. HIV trapped on the surface of FDCs remains highly infectious and genetically diverse even during drug treatment.

This major breakthrough may aid the researchers in finding out how to attack virus hidden by the reservoir cells.

"One of the biggest obstacles in treating patients with HIV is the establishment of these reservoirs that resist treatment. The ability to understand the virus in these reservoirs, and to characterize the reservoir itself, provides information with which we can begin to try to devise strategies that target the virus in these reservoirs," said Greg Burton, a BYU biochemistry professor and principal investigator on the study.

FDC will now join two other types of cells, macrophages and the latently infected CD4+ T cell, which have previously been shown to be reservoirs of HIV.

The FDCs' vault mechanism is so efficient that trapped HIV particles stay out of reach of drugs flowing through the blood stream, leading to persistent infection. It was challenging for researchers to break inside to investigate whether FDCs harbour infectious forms of the virus.

"This is a rare cell, and its long arms tend to grab onto the tissues in which it is found. So when you try to get them to release those arms so we can separate the different cells, they don't like to do that and the cell can get destroyed in the process," said Burton.

Suzanne Gartner, an HIV virologist at Hopkins, and Burton devised a method of getting into the FDCs, which involves gently digesting tissue with enzymes, then separating FDCs with a cell sorter and specific antibodies that react with FDCs. As expected, they found infectious HIV trapped on the surface of FDCs.

The scientists wanted to know if FDCs were stocked with the virus upon infection and if they continued to acquire samples of the virus over time.

The genetic makeup of HIV changes as it multiplies inside the body. If untreated, the virus is free to roam and sees more genetic variations and when treated, the virus does not replicate as often and fewer mutations occur.

Biologist Keith Crandall used a pair of supercomputer clusters at BYU, for constructing the viruses' family tree for three patients from Johns Hopkins. Blood samples taken at different points in time gave reference points to establish a time frame for different versions of the virus recovered from FDCs.

"It turned out the data matched the hypothesis that one, the FDC is a reservoir, and two, it's actually acquiring genetic variance throughout the course of mutation. We saw the accumulation of drug-resistant mutation, and saw exceptionally high genetic variation. This makes treatment extremely difficult," said Crandall.

The study will appear in the June issue of the Journal of Virology.

Source: ANI
RAS/L
Advertisement

Post your Comments

Comments should be on the topic and should not be abusive. The editorial team reserves the right to review and moderate the comments posted on the site.
User Avatar
* Your comment can be maximum of 2500 characters
Notify me when reply is posted I agree to the terms and conditions
Private,Quick,Easy,& Confidental Blood Testing
Screening
This screening panel uses your blood and urine to allow for a convenient, confidential and trouble-free way to find out if you or your partner have been exposed to HIV or another sexually transmitted disease (STD). Just being exposed may not mean you have an active infection, but if you are infected you may not have any symptoms. So without symptoms you still are at risk of transmitting this disease to a sexual partner. Early detection can also prevent the development of serious medical problems. STD's are one of the most common causes of infertility in women.
• Chlamydia and Gonorrhea Test
• Hepatitis C Antibody
• HIV 1 Antibody
• Hep B, HSVI & II Igm, RPR
Special Notes:
In 2006, over one million Americans were living with HIV/AIDS, and it is estimated that about 40,000 new cases are diagnosed each year in the United States alone.

guest Thursday, May 15, 2008

You May Also Like

Advertisement
View All