['Human umbilical cord mesenchymal stem cells (UC-MSCs) can regulate the function of immune cells. However, whether and how UC-MSCs can modulate the function of Vγ9Vδ2 T cells has not been fully understood.', 'The PBMCs or Vγ9Vδ2 T cells were activated and expanded with pamidronate (PAM) and interleukin-2 (IL-2) with or without the presence UC-MSCs. The effects of UC-MSCs on the proliferation, cytokine expression, and cytotoxicity of Vγ9Vδ2 T cells were determined by flow cytometry. The effects of UC-MSCs on Fas-L, TRAIL-expressing Vγ9Vδ2 T cells, and Vγ9Vδ2 T cell apoptosis were determined by flow cytometry.', 'UC-MSCs inhibited Vγ9Vδ2 T cell proliferation in a dose-dependent but cell-contact independent manner. Coculture with UC-MSCs reduced the frequency of IFNγ+ but increased granzyme B+ Vγ9Vδ2 T cells. UC-MSCs inhibited the cytotoxicity of Vγ9Vδ2 T cells against influenza virus H1N1 infected A549 cells and also reduced the frequency of Fas-L+, TRAIL+ Vγ9Vδ2 T cells but failed to modulate the apoptosis of Vγ9Vδ2 T cells.'] Do human Umbilical Cord Mesenchymal Stem Cells Inhibit the Function of Allogeneic Activated Vγ9Vδ2 T Lymphocytes In Vitro?