The Time is Crucial for Ex Vivo Expansion of T Regulatory Cells for Therapy

• Main Authors: Natalia Marek, Maria Bieniaszewska, Adam Krzystyniak, Jolanta Juścińska, Jolanta Myśliwska, Piotr Witkowski, Andrzej Hellmann, Piotr Trzonkowski M.D., Ph.D
• Format: Article
• Language: English
• Published: SAGE Publishing 2011-12-01
• Series: Cell Transplantation
• Online Access: https://doi.org/10.3727/096368911X566217
• ISSN: 0963-6897; 1555-3892

Ex vivo expanded CD4 + CD25 high CD127 - T regulatory cells (Tregs) are recognized as a promising candidate for immunosuppressive therapy in humans. However, due to the plasticity of Tregs lineage and artificial environment present during ex vivo expansion, Tregs easily lose suppressive activity. Here, we followed expanding CD4 + CD25 high CD127 - Tregs and their naive (CD45RA + ) and memory-like (CD45RA - ) subsets in order to establish the best conditions of the expansion. We found that, regardless of the phenotype sorted, expanding Tregs were undergoing changes resembling homeostatic proliferation and transformed into effector memory-like cells which produced not only suppressive interleukin-10 (IL-10) but also IL-6, IL-17, and interferon-γ (IFN-γ). With the time ex vivo, Tregs were losing the expression of FoxP3 and suppressive activity both when stimulated and when at rest. The only variable that helped preserve suppressive abilities of Tregs was the limitation of the time of ex vivo cultures to 2 weeks only. According to our study, the highest number of highly suppressive Tregs could be yielded with CD4 + CD25 high CD127 - Tregs cultured no longer than 2 weeks. Thorough quality check, preferentially with the assessment of FoxP3 expression and IFN-γ suppression assay, should be applied to assess suppressive activity of the cells.