VIRAL-INFECTION OF BOVINE BRONCHIAL EPITHELIAL-CELLS INDUCES INCREASED NEUTROPHIL CHEMOTACTIC ACTIVITY AND NEUTROPHIL ADHESION

1. Acute bronchitis secondary to viral infection is associated with an influx of neutrophils. We hypothesized that bronchial epithelial cell s are capable of releasing neutrophil chemotactic activity in response to viral infection. 2. To test this hypothesis, primary cultures of b ovine bronchial epithelial cells were inoculated with a bovine respira tory pathogen, bovine herpes virus-1.3. Supernatants collected from in oculated cells, before signs of toxicity, demonstrated significant neu trophil chemotactic activity using a blind well chamber neutrophil che motaxis assay. Lipoxygenase inhibitors markedly reduced the amount of neutrophil chemotactic activity released after bovine herpes virus-1 i noculation. Analysis of arachidonic acid metabolites in cell supernata nts by reverse-phase h.p.l.c. confirmed that leukotriene B4, a potent neutrophil chemoattractant, was released. 4. We also confirmed that ad hesion of neutrophils to bovine herpes virus-1-inoculated bronchial ep ithelial cells was increased and mediated in part by the neutrophil in tegrin, LFA-1. 5. Thus, virally infected airway epithelial cells relea se leucocyte chemoattractants and hence adhesive interactions, functio ns that are likely to be important in the inflammatory acute response to viral infection.