In a blinded screen of cannabinoids and terpenes, CBD and THC suppressed activation of both regulatory T cells and inflammatory Th17 cells, reducing key cytokine secretion from human immune cells.
Immunology researchers and those studying cannabinoid effects on the immune system
CBD suppressed both pro- and anti-inflammatory T cell types
What the researchers found
In an initial blinded screen at 20uM, cannabigerol, caryophyllene oxide, and gamma-terpinene reduced cytotoxicity and expression of multiple inflammatory genes. THC suppressed T cell activation and reduced IL-6 and IL-10 secretion. In dose-response experiments, CBD significantly suppressed both Treg and Th17 cell activation at 50uM, with reduced IL-6 and IL-10 secretion.
Why it matters
This is the first evidence that CBD and THC suppress both pro-inflammatory (Th17) and anti-inflammatory (Treg) immune cell responses, suggesting cannabinoids have broad immunomodulatory effects rather than simply being "anti-inflammatory."
The numbers in context
Initial screen: 20uM of each compound. 6 healthy donors. CBG, caryophyllene oxide, gamma-terpinene: reduced IL6, IL10, TNF, TRPV1, CNR1, HTR1A, FOXP3, RORC, NFKB1 expression. CBD dose-response: suppressed Treg (p<0.05) and Th17 (p<0.05) activation. CBD 50uM: reduced IL-6 (p<0.01) and IL-10 (p<0.01).
How the study worked
In vitro study using human PBMCs from 6 healthy donors, activated with CD3/CD28 and LPS. Cannabinoids and terpenes were coded to blind investigators. Flow cytometry measured Treg and Th17 responses. qRT-PCR measured gene expression. ELISA quantified cytokine secretion.
What this study cannot tell us
In vitro study using isolated immune cells, which may not reflect immune responses in a whole organism. Concentrations tested (20-50uM) may not be achievable in vivo. Small number of donors (n=6). Only acute exposure tested.
How to read the evidence
Well-designed blinded in vitro study, but isolated cell culture findings have limited clinical applicability.
When this study was published
2024 study
The bigger picture
The dual suppression of both pro- and anti-inflammatory T cells may explain why cannabinoids show complex effects in autoimmune and inflammatory conditions. It also raises questions about long-term immune function in regular cannabis users.
Questions still open
- Does the dual Treg/Th17 suppression translate to in vivo immunosuppression? Could long-term cannabis use impair immune regulation? Would lower, more physiological concentrations show the same pattern?
Common questions
Are cannabinoids anti-inflammatory?
Which cannabinoids affected the immune system most?
Read the original research
Anti-inflammatory effects of phytocannabinoids and terpenes on inflamed Tregs and Th17 cells in vitro.
Experimental and molecular pathology, 139, 104924
Citation
Tan, Kyle B C; Alexander, H Denis; Linden, James; Murray, Elaine K; Gibson, David S. (2024). Anti-inflammatory effects of phytocannabinoids and terpenes on inflamed Tregs and Th17 cells in vitro.. Experimental and molecular pathology, 139, 104924. https://doi.org/10.1016/j.yexmp.2024.104924
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