What makes treating HIV particularly difficult is its ability to hide, allowing it to escape drugs and avoid detection by the immune system. Once a patient stops with their medication, the virus can get back into action and spread quickly throughout the body.
Knowing where the virus favorably lurks in the body is challenging, but a group of researchers has made a great leap in this field, and this could possibly lead to a cure for HIV infection and AIDS.
For the new study published in the journal Nature Methods on March 9, Francois Villinger from the Emory University in Atlanta and colleagues wanted to find out if PET scanning, which is used to reveal the spread of cancer, could also show the location of HIV in the body. They injected monkeys infected with SIV, the monkey's version of HIV, with radioactive material that would only bind to SIV cells.
The researchers then took a PET scan, which detects the location of the sources of radiation within the body, and found that the viral protein known as gp120 can be found in a range of sites including the gut, genitals, lungs, nose and lymph nodes in the armpits and groins, albeit the antibody did not manage to get into the brain, which is believed to be a sanctuary site.
Although the scans did not reveal which specific cells the gp120 was in, tests conducted by the researchers after the monkeys were killed showed that the virus was found in the immune cells of the areas that the scan had identified.
The researchers said that while the technique does not show up the virus that is fully dormant, being able to see areas where there is low viral replication is crucial. The method used also allowed the researchers to visualize viral reservoirs.
"We developed a method to capture total-body simian immunodeficiency virus (SIV) replication using immunoPET (antibody-targeted positron emission tomography)," the researchers wrote in their study. "The administration of a poly(ethylene glycol)-modified, 64Cu-labeled SIV Gp120-specific antibody led to readily detectable signals in the gastrointestinal and respiratory tract, lymphoid tissues and reproductive organs of viremic monkeys."
The researchers said that next step would be the development of antibodies that can recognize the protein associated with the human strain of the virus. Scans made using these antibodies could help researchers who work on kick-and-kill strategies. These could also help with the investigation of rare cases where individuals with HIV seemed to have been cured.
Photo: Neil McIntosh | Flickr