Feeder Cell-Based γδ T Cell Expansion

Feeder cell-Based γδ T cell expansion will help strive to constantly improve the quality of the expanded Vγ9Vδ2 T cells while reducing the cost of therapy, thereby allowing the therapy to reach the masses efficiently. Creative Biolabs is driven to provide comprehensive feeder cell-based γδ T cell expansion services. Our scientific support helps global customers deal with any puzzles of feeder cell-based γδ T cell expansion.

Significance of γδ-T Cells Expansion

In the peripheral blood, γδ-T cells only compose 0.5 to 5% of peripheral blood mononuclear cells (PBMCs) whereas αβ-T cells make up approximately 50%. Among these circulating γδ-T cells, Vγ9Vδ2 T cells are the majority subset that has been well-studied for their anti-tumor activity but only account for less than 10% of all T cells. The infrequent nature of γδ-T cells had therefore impeded their clinical application. However, the fortuitous finding in the 1990s that bisphosphonates could activate the in vivo proliferation of Vγ9Vδ2 T cells during the treatment of bone resorption pioneered the search for more expansion methods. On this basis, derivative methods such as cytokine-based and K562 feeder cell-based protocols have been developed to achieve clinically relevant numbers for cancer immunotherapy.

Fiig.1 γδ T cells modulation using different substances. (Yazdanifar, 2020)

Introduction to Feeder Cell-Based γδ-T Cells Expansion

The various reports reviewed thus far have highlighted a need to conserve the non-γδ T cell fraction during activation by zoledronic acid (ZOL) and IL-2, and a need to consider the duration of culture such that a clinically-sufficient number of Vγ9Vδ2 T cell could be obtained for adoptive cell therapy. To generate even larger numbers of effector cells, artificial antigen-presenting cells (aAPCs) have been explored as a feeder cell-based method to provide a more sustained source of activation and costimulation. K562 is an MHC-negative human chronic erythroleukemic cell line that has been genetically modified and adapted for cell-based expansion of polyclonal CTLs and natural killer cells. K562 was initially chosen as a cellular scaffold for genetic modification because of the lack of MHC class I and class II expression prevents allogeneic responses from donor T lymphocytes.

Example of Feeder Cell-Based γδ-T Cells Expansion

Recent research used a different K562 cell line that was modified to express CD32, CD83, and CD137L instead to expand Vγ9Vδ2 T cells purified from PBMCs by FACS sorting. In this way, the expansion figures achieved an approximately 12-fold expansion by day 14 and a 10⁶ fold by day 100. Concerns with the use of K562 feeder cells for immune cell expansion lie primarily with the potential presence of residual K562 cells after co-culture and post-infusion into patients. To address this, K562 cells are gamma-irradiated to arrest their cell growth and to prevent unintended in vivo proliferation after ACT. Various studies have reported very low or undetectable levels of gamma-irradiated K562 feeder cells after 7 days of coculture. FDA regulations require that there should be less than 0.1% of detectable gamma-irradiated feeder cells in the final product. As such, immune effector cells expanded by K562 feeder cells have been approved for clinical trials by the FDA.

Services at Creative Biolabs

In the background of the increasing application of γδT cells for immunotherapy, feeder cell-based γδ-T cells expansion plays an important role in clinical research. As an industry-leading CRO company, Creative Biolabs offers high-quality customized services covering the entire program of feeder cell-based γδ-T cell expansion. Please feel free to contact us for your exclusive solution.

Reference

1. Yazdanifar, M.; et al. Gammadelta t cells: The ideal tool for cancer immunotherapy. Cells. 2020, 9(5).