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. 2016 Aug 31;186(2):249–265. doi: 10.1111/cei.12816

Figure 2.

Figure 2

Artificial antigen‐presenting cells (AAPCs) genetically modified to co‐express interleukin (IL)−15Rα and IL‐15 secrete IL‐15 and are potent stimulators of antigen‐specific T cell expansion. (a) Baf 3 cells not expressing IL‐15Rα (top panel) were sorted and then transduced with the IL‐15 gene alone. IL‐15 expressing Baf‐3 cells were cloned by limiting dilution, and individual clones were then analysed for intracellular expression of IL‐15 protein by fluorescence activated cell sorter (FACS) after 2, 5 and 7 passages (lower panel). The IL‐15 expression within Baf‐3 cells expressing IL‐15 alone was compared to Baf‐3 cells co‐expressing IL‐15Rα and IL‐15. (b) The cell culture supernatants from A2‐AAPCIL‐15Rα and A2‐AAPC co‐incubated with sIL‐15 (10–50 ng/ml) were analysed for IL‐15 in an enzyme‐linked immunosorbent assay (ELISA) 10–30 min after IL‐15 supplementation. Parallel analysis was performed for A2‐AAPC15Rα/15and Baf‐315Rα/15containing 106 cells/ml. (c) Parallel in‐vitro T cell cultures stimulated with A2‐AAPC and A2‐AAPCIL‐15Rα supplemented with either soluble IL‐2 or IL‐15 were established. Total yield of Tet+ T cells (analysed by FACS) at 7, 14, 21 and 28 days (left) is shown (error bars = standard error of the mean). The scattergraph (right) shows the overall yields of Tet+ T cells at 28 days after culture initiation for each of the six donors tested. The horizontal line = median. sIL‐15 supplemented T cells stimulated with A2‐AAPC or A2‐AAPCIL‐15Rα generated similar yields of Tet+ T cells (P = 0·7), while soluble IL (sIL)‐2‐supplemented cytotoxic T lymphocytes (CTLs) elicited significantly lower yields of Tet+ T cells (P < 0·01).