National Cancer Institute researchers have discovered a new class of protein found in sea coral that appears able to prevent HIV from entering T cells. If the proteins can be adapted for use in sexual lubricants and gels, they could offer a new form of barrier against HIV infection.
The study findings featured at the Experimental Biology 2014 meeting in San Diego on 29 April.
Senior investigator Dr. Barry O'Keefe, deputy chief of the Molecular Targets Laboratory at the Center for Cancer Research at the National Cancer Institute (NCI), said It's always thrilling when you find a brand-new protein that nobody else has ever seen before. And the fact that this protein appears to block HIV infection - and to do it in a completely new way - makes this truly exciting.
The team discovered the proteins while screening thousands of natural products extracts in an NCI biological repository. Belonging to a class called cnidarians, the proteins were found in feathery corals collected from the sea off the north coast of Australia.
Co-investigator Dr. Koreen Ramessar, an NCI research fellow, said cnidarians can block HIV without making the virus resistant to other HIV drugs, making them ideal for inclusion in anti-HIV microbicides, for which there is a pressing need. Women can use anti-HIV gels and lubricants without having to rely on a man being willing to use a condom.
Dr. O'Keefe says, 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.
After purifying the proteins, the team tested them on lab strains of HIV. They found them to be remarkably potent. Even at concentrations as low as a billionth of a gram, the proteins could block HIV and prevent the first step in the virus' transmission where it penetrates T cells in the immune system.
The cnidarians appear to bind to the virus and stop it fusing with the membrane of the T cell. Dr. Ramessar says this is completely different from what we've seen with other proteins, so we think the cnidarians proteins have a unique mechanism of action.