Comparative Analysis of Clinical-Scale IFN-γ-Positive T-Cell Enrichment Using Partially and Fully Integrated Platforms.

Background And Aims: The infusion of enriched CMV-specific donor T-cells appears to be a suitable alternative for the treatment of drug-resistant CMV reactivation or infection after both solid organ and hematopoietic stem cell transplantation. Antiviral lymphocytes can be selected from apheresis products using the CliniMACS Cytokine-Capture-System either with the well-established CliniMACS Plus (Plus) device or with its more versatile successor CliniMACS Prodigy (Prodigy).

Methods: Manufacturing of CMV-specific T-cells was carried out with the Prodigy and Plus in parallel starting with 0.8-1 × 10 leukocytes collected by lymphapheresis ( = 3) and using the MACS GMP PepTivator HCMVpp65 for antigenic restimulation. Target and non-target cells were quantified by a newly developed single-platform assessment and gating strategy using positive (CD3/CD4/CD8/CD45/IFN-γ), negative (CD14/CD19/CD56), and dead cell (7-AAD) discriminators.

Results: Both devices produced largely similar results for target cell viabilities: 37.2-52.2% (Prodigy) vs. 51.1-62.1% (Plus) CD45/7-AAD cells. Absolute numbers of isolated target cells were 0.1-3.8 × 10 viable IFN-γ CD3 T-cells. The corresponding proportions of IFN-γ CD3 T-cells ranged between 19.2 and 95.1% among total CD3 T-cells and represented recoveries of 41.9-87.6%. Within two parallel processes, predominantly IFN-γ CD3CD8 cytotoxic T-cells were enriched compared to one process that yielded a higher amount of IFN-γ CD3CD4 helper T lymphocytes. T-cell purity was higher for the Prodigies products that displayed a lower content of contaminating IFN-γ T-cells (3.6-20.8%) compared to the Plus products (19.9-80.0%).

Conclusion: The manufacturing process on the Prodigy saved both process and hands-on time due to its higher process integration and ability for unattended operation. Although the usage of both instruments yielded comparable results, the lower content of residual IFN-γ T-cells in the target fractions produced with the Prodigy may allow for a higher dosage of CMV-specific donor T-cells without increasing the risk for graft-versus-host disease.