Release of the chemokines RANTES and IL-8 by primary human corneal epithelial cells

There is mounting evidence to suggest that chemokines play an important role in the recruitment of eosinophils during an allergic response. The objective of the present study was to investigate whether primary human corneal epithelial cells (HCEs) release the chemokines 'regulated upon activation in normal T cell expressed and secreted' (RANTES) and interleukin- 8 (IL-8) after stimulation with phorbol 12-myristate 13-acetate (PMA) or selected proinflammatory and immunomodulating cytokines. Confluent primary HCE cultures were treated with various concentrations of either PMA, or the cytokines interleukin-1α (IL-1α), tumor necrosis factor-α (TNF-α), or interferon-γ (IFN-γ) in serum-free media. Culture supernatants were then collected at timed intervals, and assayed for the production of RANTES and IL-8 protein using specific enzyme-linked immunosorbent assays. Our data showed that HCEs release the chemokines RANTES and IL-8 in a time- and dose- dependent manner in response to PMA and the cytokines IL-1α and TNF-α. IFN- γ did not significantly induce the release of either RANTES or IL-8. However, a 1:1 mixture of TNF-α and IFN-γ acted synergistically in the augmentation of RANTES release. The results of the present study suggest an important role for these cytokines in the perpetuation of ocular inflammatory reactions.