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Updated: Aug 13, 2026
Isolation and Flow Cytometric Characterization of Murine Small Intestinal Lymphocytes
Published on: May 8, 2016
Phenotypic complexity of intraepithelial lymphocytes of the small intestine
1Department of Cell Biology, Upjohn Company, Kalamazoo, MI 49001.
Insights
Intraepithelial lymphocytes (IEL) in the small intestine exhibit complex phenotypes, similar to thymus cells. These findings suggest some IEL may develop outside the thymus.
Area of Science:
- Immunology
- Cell Biology
Background:
- Intraepithelial lymphocytes (IEL) are crucial immune cells in the small intestine.
- Their developmental origins and phenotypic diversity are not fully understood.
Purpose of the Study:
- To conduct a detailed phenotypic analysis of small intestine IEL.
- To compare IEL phenotypes with thymocytes and investigate potential extrathymic origins.
Main Methods:
- Multicolor fluorescence flow cytometry was used for detailed phenotypic analysis.
- Expression levels of T cell receptor (Tcr), Thy1, Ly1 (CD5), and Ly3 (CD8 beta) were examined.
Main Results:
- Significant populations of CD4+8+ (double positive; DP) IEL were identified, expressing mature T cell receptor (Tcr) levels.
- DP IEL were generally Ly3- (CD8 beta), unlike Ly3+ thymocytes. Ly3 was absent on Tcr gamma, delta IEL.
- Four distinct CD4-8+ Tcr alpha, beta IEL subsets were identified based on Thy1, Ly3, and Ly1 expression.
Conclusions:
- The IEL compartment displays cellular complexity comparable to the thymus.
- Findings support recent data suggesting some IEL may originate extrathymically.
Abstract:
A detailed phenotypic analysis of intraepithelial lymphocytes (IEL) of the small intestine was performed using multicolor fluorescence flow cytometry. CD4+8+ IEL (double positives; DP) could be detected in significant numbers in preparations from several mouse strains. DP IEL expressed Tcr alpha, beta and Thy1. Comparison of Tcr alpha, beta levels of thymocytes and IEL revealed that whereas the majority of DP thymocytes expressed low Tcr levels, DP IEL expressed high, mature T cell levels of Tcr. In addition, DP IEL were generally Ly3- (CD8 beta), unlike their thymic counterparts, which are Ly3+. Ly3 was not present on Tcr gamma, delta IEL, whereas CD4-8+ Tcr alpha, beta IEL contained Ly3- and Ly3+ subsets. The Ly3- population in either Tcr-bearing subset could be further subdivided by Thy1 expression. Ly1 (CD5) expression was also examined, and none of the Tcr gamma, delta IEL were Ly1+. Based on Thy1, Ly3, and Ly1 expression, four CD4-8+ Tcr alpha, beta IEL subsets were detected. The results indicate the cellular complexity of the IEL compartment rivals that found in the thymus. These findings are discussed in light of recent data suggesting an extrathymic origin of some IEL.
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