Stimulation of neutrophil respiratory burst and degranulation by Japanese encephalitis virus-induced macrophage derived factor.

The effects of Japanese encephalitis virus (JEV) and JEV-induced macrophage derived neutrophil chemotactic factor (MDF) on respiratory burst and granule exocytosis in neutrophils were studied and were compared with N-formyl-methionyl-leucyl-phenylalanine (FMLP). JEV-stimulated neutrophils released reactive oxygen metabolites with maximum activity between days 7 and 9. The response in mice was sensitive to anti-JEV-antisera treatment. Stimulation by MDF resulted in quick release of superoxide and granule enzymes from neutrophils upon both in-vivo and in-vitro stimulation in a dose dependent manner. The effect was abrogated by the MDF-specific antisera treatment. These responses were similar in kinetics and magnitude to those produced in response to FMLP. The respiratory burst elicited by MDF was abrogated by staurosporine, indicating that neutrophil activation and signal transduction by MDF and FMLP are dependent on protein kinase C.