VISNA-MAEDI VIRUS-INDUCED EXPRESSION OF INTERLEUKIN-8 GENE IN SHEEP ALVEOLAR CELLS FOLLOWING EXPERIMENTAL IN-VITRO AND IN-VIVO INFECTION

Visna-maedi virus is a lentivirus which causes inflammatory disorders in sheep, including a chronic interstitial lung disease resembling tha t observed in human immunodeficiency virus type 1 (HIV1) infection. In view of our previous demonstration of the production of neutrophil ch emotactic activity by alveolar macrophages, and given the lymphocytic and neutrophilic nature of the alveolar cell infiltrate in both natura lly and experimentally infected animals, we hypothesized that interleu kin-8 (IL8) could be a candidate for at least part of the chemotactic activity we described. In this study, we investigated IL8 mRNA express ion following visna-maedi virus infection. Northern analysis of total RNA using an ovine IL8-specific probe demonstrated that the IL8 gene i s upregulated in alveolar macrophages as a consequence of in vitro inf ection and in alveolar cells from experimentally infected animals. Usi ng a semi-quantitative RT-PCR method, we showed that various levels of IL8 mRNA are expressed by alveolar cells from infected animals and th at they correlate with the intensity of the lesions. In conclusion, vi sna-maedi virus is able to induce IL8 mRNA expression in sheep alveola r cells. Results from in vivo infected animals suggest that IL8 could play a role in the early build-up of visna-maedi virus-induced lesions .