Acoustic Affinity Cell Selection: a non-paramagnetic scalable technology for T cell selection from unprocessed apheresis products

Abstract

Background & Aim Acoustic Cell Processing is a unique acousto-fluidics platform technology for minimal shear manipulation of cells using ultrasonic standing waves. The platform has broad applications in the field of cell and gene therapy, e.g., cell concentration and washing, cell culturing, microcarrier/cell separation, acoustic affinity cell selection and label-free cell selection. The acoustic radiation force exerted by the ultrasonic standing wave on the suspended cells in combination with fluid drag forces and gravitational forces is used to manipulate the cells and achieve a certain cell processing unit operation, e.g., separate, concentrate, or wash. The technology is single-use, continuous, and can be scaled up, down or out. It therefore allows for a flexible and modular approach that can be customized to process a desired cell count, cell culture volume or cell concentration within a given required process time. Utilizing its proprietary multi-dimensional standing wave platform, MilliporeSigma has been developing the Acoustic Affinity Cell Selection (AACS) system for closed and automated Cell and Gene Therapy manufacturing, e.g., CAR-T immunocellular therapies. The AACS technology is a scalable acoustic affinity cell selection method using acoustic (non-paramagnetic) affinity beads for positive or negative cell selection. A multi-dimensional acoustic standing wave is then used to separate the affinity bead-cell complexes from the unbound cells, thereby completing the process of a negative or positive cell selection. Methods, Results & Conclusion In this work the AACS system has been used to capture CD4+ and CD8+ cells from unprocessed apheresis products. The AACS column and acoustic section (Fig. 1A) allow for a continuous flow of the initial cell population (pre-labeled with biotinylated antibodies) while acoustically retaining the acoustic affinity particles in the column. The affinity particles are functionalized with Neutravidin and thus capture the target cells that are kept inside the column, while the non-target cells are washed out of the column. The small scale 5mL column has a total target cell capture capacity of 1.8B cells (60mL Leukopak volume), of which 83% are retained in the column at a 92% purity (Fig. 1B). The AACS scale up system can process a full apheresis product (300-450mL) in less than 2h.