An antibody is able to suppress actions of HIV, promising a potential new treatment for the infection which can lead to acquired immunodeficiency syndrome (AIDS). Human studies show the new antibody is able to reduce populations of the virus in patients for up to 28 days.
Immune systems of people infected with the microorganism constantly adopt new antibodies to fight the virus. However, HIV mutates quickly, thwarting most efforts of the body and doctors at fighting off infection.
Rockefeller University researchers supplied patients with an antibody known as 3BNC117, a type of broadly neutralizing antibody which investigators believe may be able to fight a wide range of HIV strains.
"What's special about these antibodies is that they have activity against over 80 percent of HIV strains and they are extremely potent," said Marina Caskey of Rockefeller University.
This newly developed antibody binds to the CD4 receptor on the surfaces of immune cells, such as T helper cells, which alert the immune system to microbial invaders. This is the same receptor to which HIV attaches itself in its attack on the human immune system.
Broadly neutralizing antibodies are naturally produced by between 10 percent and 30 percent of patients infected by HIV. However, these usually take years to develop, during which time the virus usually mutates into new forms that are immune to the actions of the antibodies. Researchers are now cloning these antibodies and injecting them intravenously into patients who have not been infected long enough to develop a resistance. A single dose was found to suppress the virus for up to four weeks. Of 237 known strains of HIV, the 3BNC117 antibody was shown to be effective against 195.
The study examined 29 patients, 17 of whom were infected with HIV, while the other 12 served as a control group. Researchers tested the antibody at four doses - 1, 3, 10, and 30 milligrams.
"Among HIV-infected participants, 3BNC117 had the greatest effect on the eight participants who received the highest dose, resulting in significant and rapid decreases in viral load. HIV resistance to 3BNC117 was variable, but some individuals remained sensitive to the antibody for 28 days," the National Institute of Allergy and Infectious Diseases reports.
Subjects in the study were all able to tolerate the treatment without severe side effects. This suggests the antibody could prove useful for treatment of people infected with the potentially fatal virus.
The clinical study of the effectiveness of 3BNC117 on reducing HIV infection was profiled in the journal Nature.
Photo: NIAID | Flickr
