Coral reefs provide potent new anti-HIV proteins

April 29, 2014

Researchers have discovered a new class of proteins capable of blocking the HIV virus from penetrating T-cells, raising hope that the proteins could be adapted for use in gels or sexual lubricants to provide a potent barrier against HIV infection.

The proteins, called cnidarins, were found in a feathery coral collected in waters off Australia's northern coast. Researchers zeroed in on the proteins after screening thousands of natural product extracts in a biorepository maintained by the National Cancer Institute. "It's always thrilling when you find a brand-new that nobody else has ever seen before," said senior investigator Barry O'Keefe, Ph.D., deputy chief of the Molecular Targets Laboratory at the National Cancer Institute's Center for Cancer Research. "And the fact that this protein appears to block HIV infection—and to do it in a completely new way—makes this truly exciting."

In the global fight against AIDS, there is a pressing need for anti-HIV microbicides that women can apply to block HIV infection without relying on a man's willingness to use a condom. Koreen Ramessar, Ph.D., a postdoctoral research fellow at the National Cancer Institute and a member of the research team, said cnidarins could be ideally suited for use in such a product because the proteins block HIV transmission without encouraging the virus to become resistant to other HIV drugs.

"When developing new drugs, we're always concerned about the possibility of undermining existing successful treatments by encouraging drug resistance in the virus," said O'Keefe. "But even if the virus became resistant to these proteins, it would likely still be sensitive to all of the therapeutic options that are currently available."

The research team identified and purified the cnidarin proteins, then tested their activity against laboratory strains of HIV. The proteins proved astonishingly potent, capable of blocking HIV at concentrations of a billionth of a gram by preventing the first step in HIV transmission, in which the virus must enter a type of immune cell known as the T-cell.

"We found that cnidarins bind to the virus and prevent it from fusing with the T-cell membrane," said Ramessar. "This is completely different from what we've seen with other proteins, so we think the cnidarin proteins have a unique mechanism of action."

The next step is to refine methods for generating cnidarins in larger quantities so the proteins can be tested further to identify potential side effects or activity against other viruses. "Making more of it is a big key," said O'Keefe. "You can't strip the Earth of this coral trying to harvest this protein, so our focus now is on finding ways to produce more of it so we can proceed with preclinical testing."

The scientists discovered cnidarins while screening for proteins, a largely understudied component of natural product extracts found in the National Cancer Institute's extract repository. The institute maintains a large collection of natural specimens gathered from around the world under agreements with their countries of origin. The specimens are available to researchers across the United States.

"The natural products extract repository is a national treasure," said O'Keefe. "You never know what you might find. Hopefully, discoveries like this will encourage more investigators to use this resource to identify extracts with activity against infectious disease."

Explore further: Geranium extracts inhibit HIV-1

More information: Koreen Ramessar will present the team's findings during the Experimental Biology 2014 meeting on Tuesday, April 29 from 12:15 – 1:45 p.m. at the Mode of Action Natural Products poster session in Exhibit Halls A-D (Poster #D208), San Diego Convention Center.

Related Stories

Geranium extracts inhibit HIV-1

January 30, 2014
(Medical Xpress)—Extracts of the geranium plant Pelargonium sidoides inactivate human immunodeficiency virus type 1 (HIV-1) and prevent the virus from invading human cells. In the current issue of PLOS ONE, scientists from ...

Scientists find mechanism that helps HIV evade antibodies, stabilize key proteins

February 3, 2014
NIH scientists have discovered a mechanism involved in stabilizing key HIV proteins and thereby concealing sites where some of the most powerful HIV neutralizing antibodies bind, findings with potential implications for HIV ...

Seeing through HIV's disguises: Researchers identify 25 human proteins that may be crucial for HIV-1 infection

February 27, 2013
Studying HIV-1, the most common and infectious HIV subtype, Johns Hopkins scientists have identified 25 human proteins "stolen" by the virus that may be critical to its ability to infect new cells. HIV-1 viruses capture many ...

Scientists find the invisibility cloak that shields HIV-1 from the immune system

November 21, 2013
Of the two major types of HIV, only one, HIV-1, typically causes AIDS in infected people who don't receive treatment. A study published by Cell Press November 21st in the journal Immunity reveals how HIV-1 escapes detection ...

New target to fight HIV infection identified

October 1, 2013
A mutant of an immune cell protein called ADAP (adhesion and degranulation-promoting adaptor protein) is able to block infection by HIV-1 (human immunodeficiency virus 1), new University of Cambridge research reveals. The ...

New proteins inhibit HIV infection in cell cultures

July 24, 2012
(Medical Xpress) -- Yale Cancer Center scientists have developed a new class of proteins that inhibit HIV infection in cell cultures and may open the way to new strategies for treating and preventing infection by the virus ...

Recommended for you

Paris spotlight on latest in AIDS science

July 21, 2017
Some 6,000 HIV experts gather in Paris from Sunday to report advances in AIDS science as fading hopes of finding a cure push research into new fields.

Scientists elicit broadly neutralizing antibodies to HIV in calves

July 20, 2017
Scientists supported by the National Institutes of Health have achieved a significant step forward, eliciting broadly neutralizing antibodies (bNAbs) to HIV by immunizing calves. The findings offer insights for HIV vaccine ...

Heart toxin reveals new insights into HIV-1 integration in T cell genome

July 20, 2017
Human immunodeficiency virus (HIV)-1 may have evolved to integrate its genetic material into certain immune-cell-activating genes in humans, according to new research published in PLOS Pathogens.

Scientists capture first high-resolution image of key HIV protein transitional state

July 13, 2017
A new, three-dimensional snapshot of HIV demonstrates the radical structural transformations that enable the virus to recognize and infect host cells, according to a new study led by scientists at The Scripps Research Institute ...

Barrier to autoimmune disease may open door to HIV, study suggests

July 11, 2017
Researchers from the University of Colorado School of Medicine have discovered that a process that protects the body from autoimmune disease also prevents the immune system from generating antibodies that can neutralize the ...

Team tests best delivery mode for potential HIV vaccine

June 20, 2017
For decades, HIV has successfully evaded all efforts to create an effective vaccine but researchers at The Scripps Research Institute (TSRI) and the La Jolla Institute for Allergy and Immunology (LJI) are steadily inching ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.