Thanks to the use of radiolabelled antibodies, it is possible to detect HIV hidden in the tissues, suggest the results of studies carried out on monkeys, as reported in the Nature Methods journal.
The currently used pharmacotherapy allows the removal of HIV from the blood, but after discontinuation of medication, it reappears, as it can hide in the corners of the body, where it remains dormant or multiplies very slowly. Biopsies revealed his presence, among others in the lymphoid tissue of the intestine.
Francois Vilinger and his colleagues at Emory University in Atlanta decided to check whether HIV can be detected using the PET (positron emission tomography) method used to detect tumor metastasis. The patient is administered a substance labeled with an appropriate isotope, which accumulates in pathologically changed tissues.
The researchers used an antibody that binds to SIV, the monkey version of HIV. Radiolabelled antibodies were injected into three monkeys infected with SIV and receiving antiretroviral therapy.
PET examination, which reveals the location of radiation sources in the body, revealed the presence of the SIV protein gp120 in many places – the nose, lungs, intestines, genitals, and lymph nodes in the armpit and groin of monkeys. However, the antibodies did not make their way to the brain, in which the virus probably lurks as well.
The images obtained were not detailed enough to show which specific cells the virus was hiding in, but post-mortem examinations of the monkeys later confirmed its presence in the immune cells of the areas identified on the scan. While it is not possible to depict a dormant virus in this way, revealing a slowly replicating SIV is also a big progress.
The next step could be to develop antibodies capable of binding to the human virus (HIV) version of the gp120 protein.
According to specialists, thanks to the technique that can detect the presence of HIV, it will be easier to research drugs that completely eliminate the virus. For example, one might somehow wake up a hiding virus and then destroy it.
In addition, PET could help to better understand the rare cases of HIV infection that has been fully eradicated – for example, through bone marrow transplantation from people naturally immune to the infection. (PAP)