Long associated with the relief of certain symptoms, cannabidiol (CBD), which has no psychoactive effect, is generating growing interest in medicine. In a study published in
Mucosal Immunology, scientists reveal that it is capable of preventing infection by HIV-1 (human immunodeficiency virus type 1) in genital epithelia, by acting on all the cells of the immune system involved in its transmission.
These results pave the way for an innovative prevention strategy, yet to be confirmed in humans.
CBD, a compound with complex effects on immunity
CBD, derived from the Cannabis sativa plant, is known for its anti-inflammatory and immunomodulatory properties. Unlike other cannabinoids, it has no psychoactive effect, making it an attractive candidate for therapeutic use.
Illustration image from Unsplash
Its particularity lies in its mode of action: it notably activates the TRPV1 ion channel (transient receptor potential vanilloid 1), expressed on the surface of peripheral sensory neurons involved in pain transmission. This activation triggers the release of a neuropeptide, CGRP (
calcitonin gene-related peptide), now recognized as a key player in interactions between the nervous system and the immune system.
CGRP has an antiviral function
Previous work conducted at the Cochin Institute had already highlighted an unexpected role of CGRP: it limits HIV-1 infection by acting on Langerhans cells, located in the genital mucosa. These cells play a crucial role in the initial stages of infection, by transmitting the virus to CD4 T lymphocytes.
The scientists also showed that these cells express TRPV1, suggesting that a signal of neuronal origin could modulate their antiviral activity.
CBD blocks infection in several cell types
In this new study published in the journal
Mucosal Immunology, scientists explored the effect of CBD on several target cells of HIV-1: Langerhans cells, dendritic cells, macrophages, and CD4 T lymphocytes.
Result: CBD inhibits infection in all these cell types by activating TRPV1 and inducing the release of CGRP, but via distinct mechanisms:
- In Langerhans cells and macrophages, the antiviral effect depends on CGRP.
- In dendritic cells and CD4 T lymphocytes, other mechanisms independent of CGRP are involved.
Experiments on human tissues
ex vivo confirm these observations: CBD almost completely prevents virus transmission and blocks the formation of cellular contacts necessary for its spread.
Towards a new prevention strategy?
What could be the impact of this study? Despite the existence of preventive strategies like pre-exposure prophylaxis (PrEP), recently illustrated by the extraordinary effectiveness of long-acting injectable antiretroviral drugs, HIV-1 remains a global public health problem.
Current treatments can be expensive, difficult to access, or associated with adverse effects.
Scientists thus propose an original approach: a "CBD PrEP," based on the use of CBD-based products, particularly in the form of locally applied antimicrobials during sexual intercourse.
Such a strategy, even if it only offers partial protection, could offer several potential advantages: it would be simple to use and could be more easily accessible, particularly in resource-limited countries.