Felipe de Lara Janz^1,, Helen Dutra Leite², Sergio Paulo Bydlowski¹

Mesenchymal stem cells (MSCs) are described as undifferentiated cells with high capacity for self-renewal and differentiation ability in different tissues. MSCs are found in various locations in the adult organism as bone marrow, adipose tissue; and in fetal tissues as umbilical cord, placenta and amniotic fluid. They are able to produce and secrete a number of bioactive molecules with different effects: anti-fibrotic, angiogenic and mitogen. These cells also present a great immunomodulatory and anti-inflammatory potential described in experimental and human models. Several studies have demonstrated the ability of MSCs to suppress the proliferation and activation of T, B and NK cells in vitro and in vivo. Its low immunogenic action causes are not recognized by HLA mismatched receptor complex because they express low levels of MHC-I do not express MHC-II and costimulatory molecules CD40, CD80 and CD86. Because of these unique characteristics, MSCs arouse great interest in possible clinical applications in the therapy of diseases that affect the immune system. Although depending on the tissue microenvironment, the MSCs can also trigger inflammatory events. In this work, we described the main factors and another structures involved in MSCs immunoregulation.

mesenchymal stem cells, immunomodulation, soluble molecules