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Updated: Jul 26, 2026

Methods to Study Epithelial Transport Protein Function and Expression in Native Intestine and Caco-2 Cells Grown in 3D
Published on: March 16, 2017
Antigen uptake and trafficking in human intestinal epithelial cells
A Laiping So1, K Pelton-Henrion, G Small
1Department of Microbiology, Mount Sinai Medical Center, New York, New York 10029, USA.
Intestinal epithelial cells (IEC) internalize tetanus toxoid via endocytosis, but at a slower rate than monocytes. This antigen uptake occurs through both apical and basolateral surfaces in polarized cells.
Area of Science:
- Immunology
- Cell Biology
- Gastroenterology
Background:
- Intestinal epithelial cells (IEC) play a crucial role in mucosal immunity.
- Understanding antigen uptake mechanisms in IEC is vital for developing effective immunotherapies and vaccines.
- Conventional antigen-presenting cells (APCs) like monocytes are well-characterized for their antigen processing capabilities.
Purpose of the Study:
- To investigate the kinetics and pathways of antigen uptake in intestinal epithelial cells.
- To compare antigen uptake in IEC with that of human monocytes.
- To elucidate the intracellular trafficking of antigens within IEC.
Main Methods:
- Utilized primary intestinal epithelial cells and human colonic adenocarcinoma cell lines (DLD-1, Caco-2, HT-29).
- Employed fluoresceinated tetanus toxoid for kinetic studies and gold-labeled tetanus toxoid for electron microscopy.
- Analyzed antigen internalization via intracellular staining and electron microscopy, focusing on endosomal and lysosomal compartments.
Main Results:
- Intestinal epithelial cells showed minimal tetanus toxoid uptake within the first 30 minutes, contrasting with monocytes' rapid uptake within 5 minutes.
- Polarized Caco-2 cells demonstrated antigen internalization at both apical and basolateral surfaces.
- Electron microscopy revealed tetanus toxoid within endosomes and multivesicular bodies by 60 minutes, and in secondary lysosomes by 2 hours.
Conclusions:
- Tetanus toxoid follows an endocytic pathway in intestinal epithelial cells.
- The kinetics of antigen uptake in IEC are significantly slower compared to conventional antigen-presenting cells.
- IEC possess distinct antigen processing mechanisms that differ from professional APCs.
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