In vitro expansion and activation of natural killer cells for cell therapy.

NK cells are part of the non-specific immune response and are one of the main components of antitumor immunity. They do not need antigen stimul for thein activation but recognize damaged ( transformed ) cells by characteristic decreased expression of MHC I molecules. These natural killers become subjekt of many clinical studies based on the use of anti-tumor activity of NK cells for both solid tumors and in hemato - oncological diseases. The aim of this study was to find optimal conditions for in vitro expansion and activation of NK cells. NK cells were isolated from mononuclear cell fraction by magnetic separation and cultured in two types of media SCGM and X - VIVO 10 with the addition of interleukin-2 respectively OKT3 antibody. The influence of the mononuclear cells on proliferation of NK cells was tested. After a 6- day culture , the cells were passaged and growth of NK cells was determined using hematological analyzer and flow cytometry. Expression of the activation markers CD25 and CD336 (NKp44) was observed. All experiments were conducted under conditions of good manufacturing practice. Slightly higher gain of NK cells was observed in SCGM media without a significant differences in the other additives. Much higher number of NK cells was observed in culture with supporting irradiated mononuclear cells. There were no differences in cultures with autologous or allogeneic cells. We found that NK cells with higher proliferative potential express increasingly CD25, unlike the cells with decreased proliferation which had increased expression of CD336 marker. The work led to the definition of the optimal culture conditions for NK cells and became the basis for the further development of the medicinal product from in vitro activated NK cells