Potent induction of trained immunity by Saccharomyces cerevisiae β-glucans
Vuscan et al./Frontiers/2024
Why It Matters
This caught my attention because it's not just another β-glucan study — it shows that combining specific yeast β-glucans creates a synergistic effect that's stronger than either component alone. The trained immunity response lasted weeks and worked against completely different challenges than what trained the cells initially. That said, the human data here is just immune cells in a dish. The tumor results are mice only, and rodent cancer models notoriously don't translate well to humans.
Key Findings
- The β-glucan blend activated 4 different immune receptors (Dectin-1/CR3, TLR4, MMR) versus single β-glucans which typically hit 1-2 receptors, creating a broader immune training effect
- Human monocytes trained with this blend produced 2-3x more TNF-α and IL-6 when challenged with bacterial components 7 days later compared to untrained cells
- Pre-treating mice with the β-glucan blend reduced B16 melanoma tumor volume by 47% and MB49 bladder cancer volume by 38% compared to controls after 21 days
- The training effect required specific signaling molecules (Raf-1, Syk, PI3K) — blocking any of these pathways eliminated the enhanced immune response
- Epigenetic changes in immune cells persisted for at least 7 days, suggesting the reprogramming is durable rather than a temporary activation