Figure 3. Long-term rhIL-2 release by encapsulated genetically engineered CHO cells. Cells microencapsulated with alginate (Δ) or APA/citrate () as described in Figure 2, were cultured in T25 flasks containing 2 ml of compacted beads in 10 ml of medium that was renewed every 48 h. Medium culture samples were taken and assayed for rhIL-2 as described in Materials and Methods. The rhIL-2 production was expressed as means ± standard error of the mean of 4 independent experiments measured in duplicate. Results were expressed as mean ± (s.e.m.). Differences between groups were determined by analysis of variance (ANOVA).