Ascorbic acid promotes proliferation of natural killer cell populations in culture systems applicable for natural killer cell therapy

Cytotherapy. 2015 May;17(5):613-20. doi: 10.1016/j.jcyt.2015.01.004. Epub 2015 Mar 5.


Background aims: Natural killer (NK) cell-based immunotherapy is a promising treatment for a variety of malignancies. However, generating sufficient cell numbers for therapy remains a challenge. To achieve this, optimization of protocols is required.

Methods: Mature NK cells were expanded from peripheral blood mononuclear cells PBMCs in the presence of anti-CD3 monoclonal antibody and interleukin-2. Additionally, NK-cell progenitors were generated from CD34(+) hematopoietic stem cells or different T/NK-cell progenitor populations. Generated NK cells were extensively phenotyped, and functionality was determined by means of cytotoxicity assay.

Results: Addition of ascorbic acid (AA) resulted in more proliferation of NK cells without influencing NK-cell functionality. In more detail, PBMC-derived NK cells expanded 2362-fold (median, range: 90-31,351) in the presence of AA and were capable of killing tumor cells under normoxia and hypoxia. Moreover, hematopoietic stem cell-derived progenitors appeared to mature faster in the presence of AA, which was also observed in the NK-cell differentiation from early T/NK-cell progenitors.

Conclusions: Mature NK cells proliferate faster in the presence of phospho-L-AA, resulting in higher cell numbers with accurate functional capacity, which is required for adoptive immunotherapy.

Keywords: NK cell; ascorbic acid; cancer; cellular immunotherapy; hematopoietic stem cell.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ascorbic Acid / pharmacology*
  • Cell Culture Techniques / methods*
  • Cell Differentiation / drug effects
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / drug effects
  • Hematopoietic Stem Cells / metabolism
  • Humans
  • K562 Cells
  • Killer Cells, Natural / cytology*
  • Killer Cells, Natural / drug effects
  • Killer Cells, Natural / transplantation*
  • Stem Cells / cytology
  • Stem Cells / drug effects


  • Ascorbic Acid