Figure 1 –

A, sPLA₂ are secreted primarily from ciliated cells. Secreted total sPLA₂ activity from apical supernatant and basolateral culture media in human bronchial epithelial (HBE) cells with basal exposure to IL-13 (0, 2, 5, or 10 ng/mL). B, HBE cells were cultured for 14 d with PBS to produce a ciliated-enriched phenotype (I, II) or with IL-13 to produce goblet-enriched cells (III, IV). After washing the cells and withdrawing IL-13 for 24 h on d 15 (I-IV), the cell cultures were then exposed to IL-13 at 0 (PBS; I, III) or 5 ng/mL (II, IV) for 24 h to evaluate the direct effects of IL-13 on d 16. We measured sPLA₂ activity in apical supernatant and basolateral culture media from these cells. C, IL-13 did not inhibit sPLA₂ secretion from either cell type. Secreted sPLA₂ activity was measured in apical supernatant and basolateral culture media from ciliated cell- or goblet cell-enriched culture after basal exposure to IL-13 at 0 or 5 ng/mL for 24 h. Data are presented as the mean ± SEM from four samples. Significant differences are indicated by **P < .001 and *P < .01. PBS = phosphate-buffered saline; sPLA₂ = secretory phospholipases A₂.