By Steve Elliott
The chief psychoactive compound in marijuana appears to be able to damage and weaken the most common strain of the HIV virus, according to a recent study.
Tetrahydrocannabinol, more common known as THC, is the main psychoactive ingredient in cannabis; it's the chemical that gets you high. A synthetic form of THC was used to attack the HIV-1 virus, which represents more than 90 percent of all HIV types, reports Ian Steadman at Wired UK.
HIV interactions with the CB2 cannabinoid receptor in white blood cells, specifically in macrophages, one of the many types of white blood cells. While lymphocytes -- the main white blood cells -- do the bulk of the infection-fighting work by tracking down and destroying germs, macrophages are sort of a backup part of the immune system. Macrophages are attracted to damaged cells, which they surround and engulf.
Unfortunately, macrophages are also one of the first types of cells infected by HIV when it invades the body. HIV can live inside macrophages for months, infecting other cells.
Investigators and researching how to stop the HIV virus from infecting macrophages; doing so could dramatically reduce the speed at which infection progresses, giving time for other antiretrovirals to help keep it at bay, or even eliminate it.
The CB2 receptor in macrophages is normally stimulated when THC enters the bloodstream -- and it appears that macrophages that have their CB2 receptor stimulated are stronger at fighting and weakening the HIV-1 virus.
A team from the Temple University School of Medicine learned this when they infected macrophages with HIV-1, then exposed the cells to one of three types of synthetic THC that specifically target the CB2 receptor. A clear decrease in the rate of HIV-1 infection was revealed when, after a week, these cells were compared against a control group which hadn't received THC.
Effectively, the macrophages -- with the aid of THC -- had become better and keeping the HIV-1 virus out.
"The synthetic compounds we used in our study may show promise in helping the body fight HIV-1 infection," said pathologist Yuri Persidsky of Temple University (Persidsky is one of the study's authors). "As compounds like these are improved further and made widely available, we will continue to explore their potential to fight other viral diseases that are notoriously difficult to treat."
Here's a slightly alternative scenario, Dr. Persidsky: How about using natural, safe, plant-based THC instead of the synthetic stuff? That way, it doesn't need "improving" and it's already "widely available."
But do you know why they won't use natural THC? Because it gets you high. To avoid this supposed "side effect" (which is, of course, part of the healing), medical researchers are willing to settle for less-effective, more-dangerous synthetics.
Targeting the CB2 receptor only stimulates the macrophages; the psychoactive effects of THC are centered on the CB1 receptor. Synthetic THC can be produced to only target the CB2 receptor, producing no high.
THC has also been shown in other studies to not suppress the immune system. This seems to indicate the possibility of a future drug that, in combination with other methods, could suppress the HIV-1 virus.
The study, "Attenuation of HIV-1 replication in macrophages by cannabinoid receptor 2 agonists," was published in The Journal of Leukocyte Biology.