THC administration in mice caused marked suppression of antibody-producing spleen cells along with a general loss of spleen cellularity.
Read this if you are following the laboratory evidence on THC and immune system suppression in animal models.
Marked suppressionof antibody-producing spleen cells in mice given THC
What the researchers found
Mice immunized with sheep red blood cells and given THC showed a marked reduction in plaque-forming cells, which are the spleen cells responsible for producing antibodies. This suppression occurred alongside a general loss of spleen cellularity, meaning the overall number of cells in the spleen decreased.
The results pointed to THC having substantial effects on antibody synthesis, the process by which the immune system produces the proteins that target specific pathogens.
Why it matters
While the previous studies in this era focused on T-cells and macrophages, this study showed THC also affects the antibody-producing arm of the immune system. Together, these early animal studies painted a picture of THC broadly suppressing multiple components of immunity.
The numbers in context
- Marked suppression of plaque-forming cells (exact numbers not provided in abstract)
- General loss of spleen cellularity
- Model: mice immunized with sheep erythrocytes
How the study worked
Mice were immunized with sheep erythrocytes and administered delta-9-THC. Plaque-forming cell response (a measure of antibody production) and overall spleen cellularity were measured.
What this study cannot tell us
Animal study with injected THC at doses that may not reflect human exposure. Abstract does not report specific doses, timing, or magnitude of suppression. Mouse immune systems differ from human immune systems. No clinical outcomes were measured.
How to read the evidence
Animal study measuring one immune parameter. No human data. Preliminary mechanistic evidence.
When this study was published
Published in 1975. Part of the first wave of THC immunology research. The immune-suppressive effects of cannabinoids are now understood through receptor-level mechanisms.
The bigger picture
This study contributed to the growing body of 1970s evidence that THC suppresses immune function across multiple cell types and pathways. Modern research has since identified cannabinoid receptors on immune cells as the mechanism, and the clinical significance of these laboratory findings in humans remains debated.
Questions still open
- Does cannabis use in humans reduce antibody production to vaccines or infections?
- Is the spleen cellularity loss reversible after stopping THC?
Read the original research
Effects of delta-9-tetrahydrocannabinol on mouse spleens.
Research communications in chemical pathology and pharmacology, 11(4), 659-62
Citation
Lefkowitz, S S; Chiang, C Y. (1975). Effects of delta-9-tetrahydrocannabinol on mouse spleens.. Research communications in chemical pathology and pharmacology, 11(4), 659-62.
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