Pectin blocks TLR2-TLR1 and prevents ileitis in mice
What it found
In lab tests and in mice, pectin blocked a specific immune receptor called TLR2-TLR1 and reduced inflammation.
The effect was strongest with pectins that have a low degree of methyl esterification.
What they found
Animal and lab studies
Pectin blocks TLR2
In lab tests, pectin did not activate TLR2, TLR4, or TLR5. Instead, it strongly inhibited TLR2 activation, especially pectins with low DM. DM7 pectin suppressed TLR2 activation by 91.1% at the lowest concentration tested.
Specific to TLR2-TLR1
Pectin inhibited the TLR2-TLR1 pathway but did not affect the TLR2-TLR6 pathway. This means it blocks one type of immune signal while leaving another tolerogenic pathway intact.
Direct binding to TLR2
Pectin binds directly to TLR2 through electrostatic forces. Low-DM pectin binds more strongly than high-DM pectin. Mutating certain positively charged amino acids on TLR2 reduced binding of low-DM pectin.
Reduces cytokines in cells
In human dendritic cells and mouse macrophages, low-DM pectin reduced production of IL-6 and IL-10 after TLR2-TLR1 stimulation. The effect was similar to a TLR2 blocking antibody.
Prevents ileitis in mice
In mice with doxorubicin-induced ileitis, low-DM pectin reduced neutrophil influx and cell death in the crypts, and lowered proinflammatory cytokines TNF-α, MCP-1, GRO-α, and IL-6. The effect was similar to TLR2 blocking antibodies.
Not through SCFAs
Pectin treatment did not increase short-chain fatty acid levels in the cecum of mice. This shows the anti-inflammatory effect is not due to SCFA production by gut bacteria.
What the authors conclude
“These data suggest that low-DM pectins as a source of dietary fiber can reduce inflammation through direct interaction with TLR2-TLR1 receptors.”
Also in their conclusions
- They conclude that low-DM pectins can reduce inflammation by directly blocking TLR2-TLR1 receptors.
- They say this mechanism is independent of short-chain fatty acids produced by gut bacteria.
- They suggest that low-DM pectins could be used in dietary fiber formulations to prevent or treat inflammation.
How it was done
The authors wanted to understand how dietary fibers like pectin reduce inflammation, since the usual explanation involving short-chain fatty acids does not explain all their effects. They also wanted to know which types of pectin are most effective.
They tested different citrus pectins with varying degrees of methyl esterification on human and mouse immune cells in the lab, and then gave low-DM pectin to mice with doxorubicin-induced ileitis for 10 days.
What it can’t tell you
- The mouse model uses a specific chemical to cause ileitis, so it may not reflect other types of intestinal inflammation in people.
- The study does not show whether eating pectin in food would have the same effect as the purified pectin given to mice.
- It is not known if these findings apply to humans with inflammatory conditions.
Who paid
- Authors work at
- University Medical Center Groningen, Netherlands; Wageningen University, Netherlands; Groningen Institute for Evolutionary Life Sciences, Netherlands
The paper
- Title
- Dietary Fiber Pectin Directly Blocks Toll-Like Receptor 2-1 and Prevents Doxorubicin-Induced Ileitis
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Sahasrabudhe NM, Beukema M, Tian L, et al (2018). Dietary Fiber Pectin Directly Blocks Toll-Like Receptor 2-1 and Prevents Doxorubicin-Induced Ileitis. Frontiers in immunology. doi:10.3389/fimmu.2018.00383Free full textPubMed 29545800DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error