US researchers have solved the riddle of why some people infected with HIV do not develop Aids.
They have found a group of natural proteins that seem to inhibit the progressive infection of the virus that causes Aids.
The proteins are contained in a disease-blocking substance secreted in the blood of patients infected with HIV who never develop full-blown Aids.
In a study appearing in Sciencexpress, the researchers say they used a new protein-identification tool to analyse CAF, the anti-HIV substance.
They found that CAF contains natural disease-fighting proteins known as alpha-defensins.
"We are most gratified to help solve the mystery around CAF," said Dr David Ho, leader of the research team at Aaron Diamond Aids Research Centre in New York.
Ho says his group conducted tests that proved that three types of alpha-defensins work together to inhibit HIV.
He called the proteins "natural peptide antibodies" that work in concert to prevent HIV from reproducing.
Ho said the researchers do not understand how the defensin proteins act against HIV and are still uncertain if they can be used as a drug.
"It is not entirely clear that we can turn this discovery into a useful therapeutic," said Ho. He says the protein molecule is very large and the researchers are trying to make a smaller version that may act more powerfully against HIV.
PA