 We have recently published a new method of culturing human bone marrow-derived mesenchymal stem cells with increased immunosuppressive properties. Stem cells, which I would refer to as MSC, are important and promising immunomodulatory cell therapy that have progressed to clinical trials to prevent and treat inflammatory conditions, including transplantation reduction. MSC have natural suppressive properties, but we and others have always been looking for ways to increase MSC immunosuppression. One strategy that has been extensively studied is the pre-treatment of MSC with the pro-inflammatory cytokine interferon gamma. However, the problem with interferon gamma treatment is that the MSCs become immunogenic as they express a series of immune stimulatory molecules, including CD40 and MSC molecules that stimulate the immune system. These causes accelerated rejection of MSC before they can exert their suppressive effects. We have been trying to find alternative ways of improving the suppressive properties of MSC while retaining them in a non-immunogenic state. In this study, we describe in detail the enhanced suppressive properties of human MSC generated under the influence of interleukin 17A and compare them to interferon gamma pretreated MSC and untreated MSC. We show that human MSC pretreated with R17, termed as MSC17 in this paper, increased MSC growth potential and were able to show superior suppression on T cell responses. MSC17 fortunately suppressed PHA-induced T cell proliferation as measured in a treated thymidine assay, and the extent of T cell suppression was greater in MSC17 than in untreated MSC and interferon gamma treated MSC. Not only that, we show that MSC17 can inhibit T cell activation evident by the reduced surface CD25 expression on T cells. MSC17 also inhibits the secretion of pro-inflammatory cytokines interferon gamma, TNF alpha, and interleukin 2 expressed by activated T cells. But in addition to this, the most interesting property we discovered in this study is that the MSC also increased the number of human T-rex. Similar to MSC, regulatory T cells offer a potential cell therapy-based approach for yellow transplantation rejection and allow transplantation tolerance. MSC17 fortunately induced the generation of human T-rex from naive T-cells. Generation of sufficient number of T-rex represents a major limitation for using T-rex in therapy, and this finding represents a novel strategy to generate T-rex. Specifically, human MSC17 has translation potential and transplantation because unlike the interferon gamma treated MSC, they do not express MSC class 2 and CD40, thereby reducing their immunogenicity in addition to evidently promote the generation of human T-rex. In the future, we aim to investigate the mechanisms by which human MSC17 mediate the suppression on T cells, their mechanisms of T-rex induction, as well as the efficacy of MSC17 to prevent transplantation rejection.