CD25+CD127+Foxp3- Cells Represent a Major Subpopulation of CD8+ T Cells in the Eye Chambers of Normal Mice.

Tomasz Maślanka,Hubert Ziółkowski,Joanna Małaczewska,Natalia Ziółkowska,Susmit Suvas

doi:10.1371/journal.pone.0170021

Tomasz Maślanka, Hubert Ziółkowski + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0170021

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Journal: PloS one	Publication Date: Jan 12, 2017
Citations: 3	License type: CC BY 4.0

Affiliation: University of Warmia and Mazury in Olsztyn

Abstract

The aim of this study has been to determine whether eye chambers constitute part of the normal migratory pathway of naive CD4+ and CD8+ T cells in mouse and if natural CD4+CD25+Foxp3+ and CD8+CD25+Foxp3+ regulatory T cells are present within these eye compartments. To this aim, the cells obtained from aqueous humor (AH) of normal mice were phenotyped in terms of the expression CD4, CD8, CD25, CD127 and transcription factor Foxp3. The mean percentage of CD8+ T cells in the total AH lymphocyte population was as high as 28.69%; the mean percentage of CD8high and CD8low cells in this population was 34.09% and 65.91%, respectively. The presence of cells with the regulatory phenotype, i.e. CD25+Foxp3+ cells, constituted only 0.32% of CD8+ T cell subset. Regarding the expression of CD25, AH CD8+ T cells were an exceptional population in that nearly 85% of these cells expressed this molecule without concomitant Foxp3 expression. Despite having this phenotype, they should not be viewed as activated cells because most of them co-expressed CD127, which indicates that they are naive lymphocytes. With regard to the markers applied in the present research, CD8+CD25+CD127+Foxp3- T cells represent the most numerous subset of AH CD8+ cells. The results suggest that eye chambers in mice are an element in the normal migratory pathway of naive CD8+ T cells. The study presented herein demonstrated only trace presence of CD4+ cells in the eye chambers, as the mean percentage of these cells was just 0.56. Such selective and specific homing of CD8+ and CD4+ cells to the eye chambers is most clearly engaged in the induction and maintenance of ocular immune privilege.

Highlights

The eye is an immune privileged site where some immune responses are down-regulated or completely abolished to protect the delicate internal structures of the eye from the damage and permanent injury that could be consequences of strong inflammatory responses
The number of events within the CD4+ and DP T cell gates was too low to perform an analysis of the expression of CD25, Foxp3 and CD127 within these cells, as it was done for CD8+ T cells
The experiments reported in this paper showed that the mean percentage of CD4-CD8+ T cells within the total population of lymphocytes isolated from aqueous humor (AH) of mice was as high as 28.69% (± 9.41), while the value of this parameter for Peripheral blood (PB) was 12.76 (± 3.44) (Fig 1A and 1C)

Summary

Introduction

The eye is an immune privileged site where some immune responses are down-regulated or completely abolished to protect the delicate internal structures of the eye from the damage and permanent injury that could be consequences of strong inflammatory responses. The experiments revealed only trace presence of CD4+CD8- T cells (further referred to as CD4+ T cells) within the eye chambers, as the mean percentage of these cells in the total lymphocyte population was just 0.56% (± 0.28), while the value of this parameter for PB CD4+ T cells was 40.12 (± 8.19) (Fig 1A and 1C).

Results

Conclusion