# Intelectin-2 is a broad-spectrum antimicrobial lectin

## TL;DR

Intelectin-2 is a protein that helps defend mucosal surfaces by binding to mucus and killing bacteria, playing a key role in controlling microbial communities.

## Contribution

This study reveals intelectin-2 as a broad-spectrum antimicrobial lectin with dual roles in mucus crosslinking and microbial killing.

## Key findings

- Mouse and human intelectin-2 bind mucins and microbial glycans via calcium-coordinated carbohydrate recognition.
- Intelectin-2 selectively kills microbes but not human cells, reducing microbial viability.
- The lectin targets gram-positive and gram-negative bacteria from respiratory and gastrointestinal tracts.

## Abstract

Mammals regulate the localization, composition, and activity of their native microbiota at colonization sites. Lectins residing at these sites influence microbial populations, but their functional roles are often unclear. Intelectins are found in chordates at mucosal barriers, but their functions are not well characterized. In this study, we find that mouse intelectin-2 (mItln2) and human intelectin-2 (hItln2) engage and crosslink mucins via carbohydrate recognition. Moreover, both lectins recognize microbes within native microbial communities, including gram-positive and gram-negative isolates from the respiratory and gastrointestinal tracts. This ability to engage mammalian and microbial glycans arises from calcium-coordinated binding of carbohydrate residues within mucus and microbial surfaces. Microbes, but not human cells, bound by mItln2 or hItln2, suffer a loss of viability. These findings underscore the crucial antimicrobial role of mammalian intelectin-2 in mucosal defense, where it plays offensive (microbial killing) and defensive (mucus crosslinking) roles in regulating microbial colonization.

Intelectin-2 defends mucosal interfaces by crosslinking mucus and blocking microbial growth. This study reveals that mouse and human intelectin-2 recognizes galactose-rich glycans to bind and target diverse bacteria—uncovering a potent, dual-action lectin that shapes host–microbe balance.