Depression of chemiluminescence during dengue virus infection of mice: role of cytokines.

The effect of dengue type 2 virus (DV) and the cytokines induced by it, on the chemiluminescence (CL) response of mouse spleen cells was studied by luminol-dependent CL. Following intracerebral (i.c.) inoculation of DV, an initial increase in CL response was observed which was followed by a sharp decline from the 4th day post-infection with lowest values on days 5 and 6. DV-induced depression of CL was inhibited by pretreatment of mice with antisera against the two DV-induced cytokines, the cytotoxic factor (CF) and the cytotoxin (CF2), but antisera against the other two helper (HF) or suppressor (SF) cytokines had minimal effect. Inoculation of CF or CF2 into mice depressed the CL in dose-dependent manner at 2 hours but increased it at the 3rd day. Inoculation of HF or SF had no significant effect. Treatment of mice with the cytokines in presence of the specific antisera had an enhancing effect on the CL response. The antisera alone had no effect on CL. Thus, these findings indicate that DV infection impaired the generation of respiratory burst, and the impairment appeared to be mediated by two DV-induced cytokines (CF/CF2). Targetting of the cytokines to M phi was significantly enhanced in the presence of specific anti-cytokine antibodies.