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Updated: Aug 11, 2026
Isolation and Flow Cytometric Characterization of Murine Small Intestinal Lymphocytes
Published on: May 8, 2016
CD4+ CD8+ and CD8alpha+ beta- T lymphocytes in human small intestinal lamina propria
M Abuzakouk1, J Carton, C Feighery
1Department of Immunology, St. James's Hospital, Dublin, Ireland.
Insights
Disease-free human intestinal lamina propria contains a significant population of CD4+ CD8alpha+ T lymphocytes. These cells, which lack the CD8beta chain, are more abundant in the lamina propria than the epithelial layer, suggesting a unique role in immune regulation.
Area of Science:
- Immunology
- Gastroenterology
- Cell Biology
Background:
- The intestinal lamina propria harbors a complex T-lymphocyte population crucial for mucosal immunity.
- Understanding T-lymphocyte subsets, particularly CD8+ T cells, is vital for comprehending intestinal immune responses.
Purpose of the Study:
- To investigate the expression of CD8 on T-lymphocyte subpopulations within the healthy human intestinal lamina propria.
- To characterize the phenotype and distribution of CD8+ T cells in the lamina propria compared to the epithelial layer.
Main Methods:
- Small intestinal biopsies from disease-free individuals were processed into single-cell suspensions.
- Dual and three-color flow cytometry was employed using monoclonal antibodies against T-cell markers (CD3, CD4, CD8, CD56, CD8αβ, CD8α, TCRαβ, TCRγδ).
Main Results:
- A notable population of CD4+ CD8+ (double positive) T lymphocytes was identified in the lamina propria (14%), significantly higher than in the epithelial layer (7%).
- Within the lamina propria, double-positive T cells predominantly expressed the CD8α chain, with CD8α-only T cells being more numerous than in the epithelial layer.
- Few gamma-delta T-cell receptor (γδTCR+) T lymphocytes were found in the lamina propria (2%) compared to the epithelial layer (8%).
Conclusions:
- A distinct subset of CD4+ CD8α+ T lymphocytes, negative for the CD8β chain, exists in the human intestinal lamina propria.
- This CD4+ CD8α+ T-cell population is more prevalent in the lamina propria than in the epithelial layer.
- These findings suggest a specialized function for these unique T cells in intestinal immunoregulation.
Objective:
To examine CD8 expression by T-lymphocyte subpopulations from disease-free human lamina propria.
Methods:
Single-cell suspensions were prepared from the epithelial layer and the lamina propria of small intestinal biopsies obtained endoscopically from disease-free patients. Monoclonal antibodies against CD3, CD4, CD8, CD56, CD8alphabeta, CD8alpha, TCR alphabeta and TCR gammadelta were used for dual and three-colour flow cytometric analysis.
Results:
In addition to classical CD4+ and CD8+ T lymphocytes a substantial proportion of lamina propria T lymphocytes were CD4+ CD8+ or 'double positive' (mean 14%, range 4-26%). This population was significantly lower in the epithelial layer of the same patients (mean 7%, range 3-21%, P < 0.007). Three-colour flow cytometric analysis revealed that expression of the CD8 molecule on double positive T cells in the lamina propria was limited to the CD8alpha chain. Furthermore, of the CD8+ population, CD8+ T cells which only expressed the alpha chain were present in greater numbers in the lamina propria (mean 35%, range 14-54%) than in the epithelial layer (mean 18%, range 5-37%, P < 0.02). NK (CD56+) cells were not detected and few gammadeltaTCR+ T lymphocytes were detected in the lamina propria (mean 2%, range 0.5-6.6%) when compared with the epithelial layer (mean 8%, range 0.2-14%, P < 0.008).
Conclusion:
A significant population of CD4+ CD8alpha+ T lymphocytes which are CD8beta chain negative have been detected in the intestinal lamina propria. These cells form a more significant component of the lamina propria than the epithelial layer T-cell repertoire and may have a unique function in intestinal immunoregulation.
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