Quantitative activation suppression assay to evaluate human bone marrow-derived mesenchymal stromal cell potency.

Bahey Salem, Samantha Miner, Nancy F Hensel, Minoo Battiwalla, Keyvan Keyvanfar, David F Stroncek, Adrian P Gee, Patrick J Hanley, Catherine M Bollard, Sawa Ito, A John Barrett

Index: Cytotherapy 17 , 1675-86, (2015)

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Abstract

With the increasing use of cell therapies involving immune modulatory cells, there is a need for a simple standardized method to evaluate and compare the suppressive potency of different cell products. We used the Karpas 299 (K299) cell line as the reference suppressor cell to develop a standardized suppression assay to quantify the immune-modulatory capacity of bone marrow-derived mesenchymal stromal cells (BM-MSCs).Healthy donor CD4 T cells were co-cultured with the K299 cell line or with third-party BM-MSCs. After stimulation with anti-CD3/CD28 beads, CD154 activation and proliferation of CD4 T cells were measured to calculate suppression.The K299 cell line reproducibly suppressed both the activation and proliferation of healthy donor CD4 T cells in a dose-dependent manner. A rapid (16-h) assay that was based on activation-suppression was selected for development. In replicate testing, there was an inherent variability of suppression of 11% coefficient of variation between different responder T cells. Suppression by BM-MSCs on different responders correlated with suppression by K299. We therefore used K299 suppression as the reference to define suppression potency of BM-MSCs in K299 Suppression Units. We found that inter-donor variability, passage number, method of manufacture and exposure of BM-MSCs to steroids or interferon-γ all affected BM-MSC potency of suppression.This method provides a platform for standardizing suppressor function to facilitate comparisons between laboratories and for use as a cell product release assay.Published by Elsevier Inc.