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 A; ARIEL PODHORZER; MONTAL, S; BILLORDO ARIEL; BAZ, P; ARRUVITO,L; PODESTÁ , G; FAINBOIM LEONARDO

Vienna

Congreso; 4to Congreso Europeo de Inmunología; 2015

European Federation of Immunological Societies,Austrian Society for Allergology and Immunology

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), acting through cell-contact and the participation of CTLA-4. All studies on liver Tregs were previously performed analyzing the role of CD4+CD25+FOXP3+ T cells. Aim. Characterization of the recently described CD8+HLA-DR+ Treg within a peripheral tissue, like the liver which is known to posses tolerogenic features.Conclusions- We demonstrated that our recently described CD8+HLA-DR+ Tregs cells, represent almost 46% of the CD8+ liver cells. In healthy controls, this frequency is in clear contrast with the frequency detected of the classical CD4+FOXP3+ cells. 2- Liver CD8+HLA-DR+ and CD8+HLA-DR? have a similar differentiation phenotype. However, functional studies endorse CD8+HLA-DR+ cells with a strong secretion of IFN-γ and a higher cytotoxic effect measured by its high expression of CD107a.3- Although the liver low proliferation capacity, removal of CD8+HLA-DR+ cells seems to enhance the liver MNCs proliferative response.4- It remains to be elucidated how and by which mechanism IFN-γ and/or the cytotoxic capacity of CD8+HLA-DR+ T cells can mediate the liver suppressor effect.