Why retroviruses such as HIV love their neighbors

July 27, 2009

Retroviruses such as HIV that are already within cells are much more easily transmitted when they are next to uninfected cells than if they are floating free in the bloodstream.

"Cell-to-cell transmission is a thousand times more efficient, which is why diseases such as AIDS are so successful and so deadly," said Walther Mothes, associate professor of microbial pathogenesis at the Yale School of Medicine. "And because the retroviruses are already in cells, they are out of reach of the immune system."

Now, Yale University researchers led by Mothes and Jing Jin, a postdoctoral associate in Mothes' lab, have made movies of viral activity within cells that help explain why cell-to-cell transmission is so efficient and provide potential targets for a new generation of AIDS drugs.

Using imaging technology that can track individual particles of virus in real time, the Yale team discovered that infected cells can specifically produce viruses at the point of contact between cells, they report in the July 27 edition of the open access journal PLoS Biology. Ten times more of these particles are found at these cellular poles than elsewhere at the surface of cells, the researchers report. The ability of infected cells to specifically produce viruses only at cell-cell interfaces explains how viruses spread so efficiently, they note.

The researchers also identified a possible weakness in the transmission chain. The team found that viruses express a sticky protein that docks with uninfected cells and then attracts viral assembly to these sites. If this adhesion molecule lacked a "cytoplasmic tail," then the viral particles did not assemble at the jumping off point between cells.

Mothes expects many more such targets will be identified as scientists work out the mechanics of cell-to-cell transmission.

"We are just opening the door to this whole process," Mothes said. "It is a black box, and many, many cellular factors have to be involved in making this happen. Our hope is that somewhere down the road we will have a completely new anti-viral strategy based on targeting cell-to-cell transmission."
-end-
Nathan M. Sherer was another Yale-affiliated author of the paper.

The work was funded by the National Cancer Institute and amfAR, The Foundation for AIDS Research.

Yale University

Related HIV Articles from Brightsurf:

BEAT-HIV Delaney collaboratory issues recommendations measuring persistent HIV reservoirs
Spearheaded by Wistar scientists, top worldwide HIV researchers from the BEAT-HIV Martin Delaney Collaboratory to Cure HIV-1 Infection by Combination Immunotherapy (BEAT-HIV Collaboratory) compiled the first comprehensive set of recommendations on how to best measure the size of persistent HIV reservoirs during cure-directed clinical studies.

The Lancet HIV: Study suggests a second patient has been cured of HIV
A study of the second HIV patient to undergo successful stem cell transplantation from donors with a HIV-resistant gene, finds that there was no active viral infection in the patient's blood 30 months after they stopped anti-retroviral therapy, according to a case report published in The Lancet HIV journal and presented at CROI (Conference on Retroviruses and Opportunistic Infections).

Children with HIV score below HIV-negative peers in cognitive, motor function tests
Children who acquired HIV in utero or during birth or breastfeeding did not perform as well as their peers who do not have HIV on tests measuring cognitive ability, motor function and attention, according to a report published online today in Clinical Infectious Diseases.

Efforts to end the HIV epidemic must not ignore people already living with HIV
Efforts to prevent new HIV transmissions in the US must be accompanied by addressing HIV-associated comorbidities to improve the health of people already living with HIV, NIH experts assert in the third of a series of JAMA commentaries.

The Lancet HIV: Severe anti-LGBT legislations associated with lower testing and awareness of HIV in African countries
This first systematic review to investigate HIV testing, treatment and viral suppression in men who have sex with men in Africa finds that among the most recent studies (conducted after 2011) only half of men have been tested for HIV in the past 12 months.

The Lancet HIV: Tenfold increase in number of adolescents on HIV treatment in South Africa since 2010, but many still untreated
A new study of more than 700,000 one to 19-year olds being treated for HIV infection suggests a ten-fold increase in the number of adolescents aged 15 to 19 receiving HIV treatment in South Africa, according to results published in The Lancet HIV journal.

Starting HIV treatment in ERs may be key to ending HIV spread worldwide
In a follow-up study conducted in South Africa, Johns Hopkins Medicine researchers say they have evidence that hospital emergency departments (EDs) worldwide may be key strategic settings for curbing the spread of HIV infections in hard-to-reach populations if the EDs jump-start treatment and case management as well as diagnosis of the disease.

NIH HIV experts prioritize research to achieve sustained ART-free HIV remission
Achieving sustained remission of HIV without life-long antiretroviral therapy (ART) is a top HIV research priority, according to a new commentary in JAMA by experts at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

The Lancet HIV: PrEP implementation is associated with a rapid decline in new HIV infections
Study from Australia is the first to evaluate a population-level roll-out of pre-exposure prophylaxis (PrEP) in men who have sex with men.

Researchers date 'hibernating' HIV strains, advancing BC's leadership in HIV cure research
Researchers have developed a novel way for dating 'hibernating' HIV strains, in an advancement for HIV cure research.

Read More: HIV News and HIV Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.