congresos y reuniones científicas
The analysis of highly purified human liver cells reveals that in comparison with CD4+FOXP3+ cells, CD8+DR+ are the predominant Treg within the liver microenvironment
MACHICOTE, ANDRÉS; PODHORZER, A; MONTAL, S; BILLORDO, A; BAZ, P; ARRUVITO, L; PODESTA, G.; FAINBOIM, L
Congreso; 4th European Congress of Immunology; 2015
Introduction: We have shown that CD8+ T cells from both adult peripheral blood and umbilical cord blood mononuclear cells constitutively expressing HLA-DR represent a natural human CD8+ regulatory T cell subset (Tregs). All studies on liver Tregs were previously performed analyzing the role of CD4+CD25+FOXP3+ T cells. We aim to compared their presence in the liver with CD8+HLA-DR+ Treg cells.Material and Methods: T cells markers were analyzed on MNCs from PB healthy controls (N=32) or from liver perfusion collection from donor livers (N=10), and detected by flow cytometry. Depletion of CD8+DR+ from liver MNCs was achieved by cell sorting with a FACSAria II flow cytometer. Detection of FOXP3 with anti-FOXP3 antibody was performed using fixed and permeabilized cells following the manufacturer?s instructions. Results: Liver CD8+ T cells represent 60% of CD3+ cells, CD4 T cells constitute around 20% of liver T cells, and CD4+CD25+FOXP3+ were only detected in 1.7%±1.4 of these CD4+ T cells. Liver CD8+HLA-DR+ T cells account for 49,2%±15 of total CD8+ cells (n=10) Vs 14.4%±3.5 in PB (n=32). The suppressive capacity of CD8+HLA-DR+ T cells in response to PHA or CD3/CD28 was determined after its depletion from liver MNCs. The experiments showed an enhanced response of 45%. When CD8+HLA-DR+ were added back to liver CD8+HLA-DR+-depleted MNCs at a 1:10 dilution, a strong proliferative suppressor effect was detected (>50%). Conclusions: We demonstrated for the first time the high frequency and strong suppressor effect of this naturally occurring liver CD8+HLA-DR+ T cells.