Researchers at MIT have identified that the lectin intelectin-2 possesses broad-spectrum antimicrobial activity against bacteria in the gastrointestinal (GI) tract and contributes to strengthening the mucus barrier.
Intelectin-2's Dual Mechanism
Intelectin-2 operates in two main ways: by stabilizing the mucus layer and by directly neutralizing or restraining bacteria.
- Mucus Stabilization: Intelectin-2 binds to galactose, a sugar found in mucins (molecules that form mucus). This binding helps reinforce the mucus barrier lining the GI tract.
- Antimicrobial Activity: It also binds to galactose present on the surfaces of various bacterial cells, including pathogens that cause GI infections. This binding traps the bacteria, hinders their growth, and can lead to their disintegration by disrupting cell membranes. This activity has been observed against bacteria, including some antibiotic-resistant strains like Staphylococcus aureus and Klebsiella pneumoniae.
Research Background and Findings
Human mucosal surfaces contain defensive molecules, including lectins, which are proteins that recognize microbes by binding to cell surface sugars. Intelectin-2 is one such lectin.
The study, published in Nature Communications, involved researchers Laura Kiessling, Amanda Dugan, and Deepsing Syangtan. While intelectin-1, another human intelectin, binds exclusively to carbohydrates in bacteria, intelectin-2's functions were less understood. The team found that both human and mouse intelectin-2 bind to galactose.
In humans, intelectin-2 is produced by Paneth cells in the small intestine. In mice, its expression by Goblet cells can be triggered by inflammation and parasitic infections.
Therapeutic Potential
This broad-spectrum antimicrobial activity suggests intelectin-2 could be developed as a therapeutic agent. It may also be used to strengthen the mucus barrier in patients with conditions like inflammatory bowel disease (IBD), where intelectin-2 levels can be imbalanced.
The researchers suggest that restoring correct intelectin-2 levels could benefit IBD patients and that harnessing human lectins offers a new strategy to combat antimicrobial resistance.