Enhanced expression of IL‐8 in normal human keratinocytes and human keratinocyte cell line HaCaT in vitro after stimulation with contact sensitizers., tolerogens and irritants

Abstract To investigate the interleukin‐8 production of keratinocytes after stimulation in vitro we have used various agents: (i) contact sensi‐tizer (2,4‐dinitrofiuorobenzene, 3‐n‐penladecylcatechol); (ii) tolerogen (5‐methyl‐3‐n‐pentadecylcatechol); (iii) irritant (sodium lauryl sulfate). Interleukin‐8 gene expression was assessed by northern blot hybridization of the total cytoplasmic RNA extracted from subconfluent normal human keratinocyte cultures and the keratinocyte cell line HaCaT using a radiolabeled DNA probe specific for human interleukin‐8. Intcrleukin‐8 gene expression was markedly increased upon in vitro stimulation after 1‐6 h with contact sensitizers, tolerogen and the irritant. In contrast, in‐terlcukin‐8 production was not detectable in unstimulatcd normal human keratinocytes or the HaCaT keratinocyte cell line. These results suggest that the induction and production of interleukin‐8 is a response to nonspecific stimuli and may play a critical role in the early response to immuno‐genic or inflammatory signals in man.