High cell density cultivation of human leukemia T cells (Jurkat cells) in semipermeable polyelectrolyte microcapsulesThe ex vivo expansion of human T cells is of considerable scientific and medical interest. Currently, this requires the addition of massive amounts of stimuli. Here, human leukemia T cells (Jurkat cells) were used as model cells to demonstrate the in vitro expansion of T cells in the absence of added stimuli after encapsulation in semipermeable sodium cellulose sulfate/poly(diallyldimethyl) ammonium chloride polyelectrolyte membrane capsules (molecular weight cutoff <10 kDa, average diameter ca. 800 μm). For comparison, free and encapsulated cells were cultivated in standard T-flasks and spinner bottles (both 50 mL culture medium) as well as in hanging drops (35 μL, only nonencapsulated cells). Encapsulation led to a significantly higher specific growth rate, a prolonged exponential growth phase together with a reduced tendency for apoptosis, as evidenced by shifts in the cell cycle distribution toward the S and G2/M phases together with a reduced percentage of cells in the sub-G0/G1 phase. As a consequence, very high cell densities (>140×10 6 cells/mL capsule ) were obtained in the capsules, particularly for the spinner cultivations. No evidence for nonspecific activation/stimulation, that is IL-2 and CD25 expression, was found, while specific stimulation by phorbol-12-myristate-13-acetate/ionomycin was still possible. Since Jurkat cells commonly serve as model cells for primary T lymphocytes, the proposed method may present a strategy for high-density proliferation of primary human T lymphocytes.

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