Viral infection of bovine bronchial epithelial cells induces increased neutrophil chemotactic activity and neutrophil adhesion

Acute bronchitis secondary to viral infection is associated with an influx of neutrophils. We hypothesized that bronchial epithelial cells are capable of releasing neutrophil chemotactic activity in response to viral infection. To test this hypothesis, primary cultures of bovine bronchial epithelial cells were inoculated with a bovine respiratory pathogen, bovine herpes virus-1. Supernatants collected from inoculated cells, before signs of toxicity, demonstrated significant neutrophil chemotactic activity using a blind well chamber neutrophil chemotaxis assay. Lipoxygenase inhibitors markedly reduced the amount of neutrophil chemotactic activity released after bovine herpes virus-1 inoculation. Analysis of arachidonic acid metabolites in cell supernatants by reverse-phase h.p.l.c. confirmed that leukotriene B₄, a potent neutrophil chemoattractant, was released. We also confirmed that adhesion of neutrophils to bovine herpes virus-1-inoculated bronchial epithelial cells was increased and mediated in part by the neutrophil integrin, LFA-1. Thus, virally infected airway epithelial cells release leucocyte chemoattractants and hence adhesive interactions, functions that are likely to be important in the inflammatory acute response to viral infection.