CBD suppressed T cell function by deregulating NFAT and AP-1 transcription factors, and this immune suppression occurred even in mice completely lacking both CB1 and CB2 cannabinoid receptors.
Read this if you take CBD regularly and want to understand its effects on the immune system at a molecular level.
CBD suppressed T cells through NFAT, independent of both CB1 and CB2 receptors
What the researchers found
Building on previous findings that CBD suppresses IL-2 production, researchers investigated the mechanism and found CBD has broad immunosuppressive effects on T cells.
CBD suppressed production of IL-2 and IFN-gamma (key immune signaling molecules), inhibited T cell proliferation, reduced surface expression of the activation marker CD25, and suppressed antibody production in response to a standard immune challenge.
The mechanism involved suppression of two critical transcription factors: AP-1 and NFAT, which are essential regulators of T cell activation and cytokine production.
Critically, these immunosuppressive effects persisted in splenocytes from mice completely lacking both CB1 and CB2 receptors, proving CBD's immune effects operate through an entirely different pathway than traditional cannabinoid signaling. However, the CB1/CB2 knockout mice had a generally weaker immune response, showing these receptors do play a role in baseline immune function.
Why it matters
This study identified a specific molecular mechanism for CBD's immune suppression (NFAT/AP-1 deregulation) and proved it doesn't require either known cannabinoid receptor. This has implications for autoimmune disease treatment but also raises questions about whether regular CBD use could compromise immune function.
The numbers in context
CBD suppressed IL-2 and IFN-gamma production, CD25 expression, T cell proliferation, and anti-sRBC IgM antibody responses. Effects persisted in CB1/CB2 double-knockout mice. AP-1 and NFAT transcriptional activity were suppressed.
How the study worked
Murine splenocytes and purified T cells were treated with CBD and assessed for cytokine production, proliferation, surface marker expression, and antibody responses. Transcription factor activity was measured. CB1/CB2 double-knockout mice were used to determine receptor involvement.
What this study cannot tell us
In vitro mouse immune cell studies may not predict human immune responses. The CBD concentrations used may not reflect achievable human tissue levels. Only acute exposure was examined.
How to read the evidence
This is a well-designed mechanistic study using knockout mice to confirm receptor independence, providing moderate evidence for a specific CBD immune mechanism.
When this study was published
Published in 2008. CBD's non-cannabinoid receptor targets have been further investigated, with several additional molecular targets identified since.
The bigger picture
This study provided one of the clearest molecular mechanisms for CBD's immunosuppressive effects and definitively showed these effects don't work through cannabinoid receptors. The NFAT pathway is also targeted by cyclosporine, a powerful immunosuppressant used in organ transplantation, placing CBD's immune effects in a clinically relevant context.
Questions still open
- Could CBD's NFAT suppression be therapeutically exploited for autoimmune conditions? Does regular oral CBD use in humans measurably suppress immune function? What is CBD's non-cannabinoid receptor target for these immune effects?
Common questions
What is NFAT?
Could CBD weaken my immune system?
Read the original research
The profile of immune modulation by cannabidiol (CBD) involves deregulation of nuclear factor of activated T cells (NFAT).
Biochemical pharmacology, 76(6), 726-37
Citation
Kaplan, Barbara L F; Springs, Alison E B; Kaminski, Norbert E. (2008). The profile of immune modulation by cannabidiol (CBD) involves deregulation of nuclear factor of activated T cells (NFAT).. Biochemical pharmacology, 76(6), 726-37. https://doi.org/10.1016/j.bcp.2008.06.022
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