AUTOLOGOUS MONOCYTE-MEDIATED HUMAN CD4+TREG EXPANSION

Abstract

CD4+Foxp3+regulatory T cells (Tregs) implies huge importance in regulating immune activation and autologous self-tolerance. In transplantation, the concern of immunosuppressants could be reduced by using adoptive autologous Tregs. However, the limitation of current Tregs expansion protocols are the small number of expanded cells. In this study, our lab managed to expand human Tregs ex-vivo using autologous monocytes cells which could dramatically improve the expansion rate. Here we evaluated the possible therapeutic application of consistently ex-vivo expanded human CD4+CD25+FoxP3+T cells from gated CD4+CD25hiCD127- population. Ex-vivo enriched CD4+CD25+CD127-T cells were successfully and consistently expanded to 5,000-8,800 times from the initial culture for 10 days with optimized culture conditions. A high concentration of IL-2(>500units) and TGF-beta together with anti-CD3 and anti-CD28 stimulation were essential to the massive ex-vivo expansion. Expanded Tregs showed 99% of FoxP3 expression and expressed high level of CD25, CD95, CD47 as well as maintain the suppressive capacity. Thus, we proved that ex-vivo expanded CD4+Treg retain regulatory activity and could match the requirement for cells therapy.