na？ve rat nk cells control the onset of t cell response天真鼠nk细胞控制t细胞反应的发生.pdfVIP

¨ Naıve Rat NK Cells Control the Onset of T Cell Response 1. 1. 1 2 Lilli Kraus , Britta Trautewig , Juergen Klempnauer , Thorsten Lieke * 1Transplant Laboratory, Department of General-, Visceral- and Transplantation Surgery, Hannover Medical School, Hannover, Germany, 2 ReMediES, Department of General-, Visceral- and Transplantation Surgery, Hannover Medical School, Hannover, Germany Abstract NK cell function in the rat is only defined in a rudimentary way due to missing tools for clear NK cell identification. The present study introduces the congenic LEW.BH-NKC rat strain which allows distinct detection of rat NK cells using commercial antibodies. LEW.BH-NKC rats were exposed in vivo to the porcine B cell line L23 by subcutaneous transfer of L23 cell suspension. We used Luciferase transgeneic L23 cells to follow the course of rejection by living imaging. L23 cells were rejected within five days after placement under the skin thus the rejection is mediated by innate immune responses in the first place. Indeed we found increased percentages of NK cells in the blood, spleen and in draining lymph nodes using flow cytometry methods. Surprisingly, we found as a consequence a decrease in proliferative T cell response in the draining lymph nodes. We identified NK cells as mediators of this regulation by in vitro performed mixed lymphocyte reactions. The remarkable feature was the naive state of NK cells exhibiting the regulative capacity. Furthermore, the regulation was not exclusively mediated by IL-10 as it has been reported before for influence of T cell response by activated NK cells but predominantly by TGF-b. Interestingly, after initiation of the adaptive immune res