Evaluation of NKp46+CD57+NKcells derived from cord blood stem cells

Abstract

Introduction: Natural killer cells are one of the main particles of innate immune system and have an important role in host defense against cancers. These cells are capable of destroying tumor cells without damage to normal tissue; hence, the antitumor effect of NKcell would be performed without leading to graft versus host disease. In addition, immunotherapy by NKcell could decrease resistance of tumor cells to chemotherapy, and also it can be useful in destroying cancerous stem cells and mircometastasis. The morphological analysis of NKcell has shown that most of these cells, express specific surface antigens. One of these important antigens is CD57. It has been demonstrated that, the amount of CD57 expression on NKcell surface, is associated with their activity against virus infected and tumor cells. Therefore, it is important to conduct a survey about the amount of antigen expression on NKCell derived from umbilical cord blood and its association with their cytotoxicity. Material and methods: The blood, derived from umbilical cord, was collected in special heparinized flasks. CD34+NKcells separation performed using Ficoll-Paque based on density difference. CD34+ cells were magnetically labeled and placed in MACS column and separated from non CD34+ cells. CD34+cells were cultured in presence of cytokines (IL_2, IL_7, IL_15, IL_21, Flt_3 and SCF) and evaluated by flow cytometer on days 14 and 21. Results: There was a slight increase in NKp46 expression, in presence of cytokines. Unlike NKp46, a noticeable increase in CD57 and CD107 expression after induction with cytokines was seen. The production of IFN_γ increased in cytokine included specimen.