The Effects of Anti-CD3/CD28 Coated Beads and IL-2 on Expanded T Cell for Immunotherapy.

BACKGROUND

The activation of peripheral blood mononucleated cells (PBMCs) with anti-CD3/CD28-coated magnetic beads promotes intrinsic resistance to HIV as well as cell expansion.

OBJECTIVES

The aim of this study was to define an optimal cell isolation protocol for the expansion of PBMCs using anti-CD3/CD28-coated bead stimulation, with the ultimate goal of using these cells for adoptive therapy.

MATERIAL AND METHODS

PBMCs were isolated from healthy donor blood samples. To determine the effect of varying the bead-to-cell ratios on the expansion rate and phenotypic characterization of the expanded cells, one million PBMCs were stimulated by anti-CD3/CD28-coated beads at bead-to-cell ratios of 0.1 : 1, 0.5 : 1 and 1.0 : 1 in the presence of 100 U/mL exogenous IL-2; also, one million PBMCs were stimulated by anti-CD3/CD28-coated beads at a bead-to-cell ratio of 0.5 : 1 in the presence of varying concentrations of IL-2 (20, 100 and 1000 U/mL). Cell expansion was carried out for three weeks. The cell numbers, cell viability and phenotypic characterization were determined by trypan blue exclusion and flow cytometry.

RESULTS

The initial experiments showed no difference in the expansion rate from cells grown with the three different bead-to-cell ratios. PBMCs can be expanded up to 1000-fold at a 0.5 : 1 bead-to-cell ratio after three weeks of cell expansion with a high viability (90%). Furthermore, in the presence of 100 U/mL IL-2, the percentages of CD3-CD16+CD56+ cells showed marked increases.

CONCLUSIONS

The results demonstrate that PBMCs were stimulated with anti-CD3/CD28-coated beads. This method may provide an alternative for driving T cell expansion, which may be very useful in adoptive immunotherapy.