title: Production of nitrite by dengue virus-induced cytotoxic factor.
abstract: Dengue type 2 virus (DV) infection induces production of a cytokine, the cytotoxic factor (CF) in the spleen of mice. The present study was undertaken to investigate the production of nitrite (NO2-) by the spleen cells of mice in vitro and in vivo following inoculation of DV or CF. Maximum NO2- production occurred at 45 min after inoculation of 5 microg CF, both in vitro and in vivo. The NO2- was produced by macrophages and T cells and not by B cells. Pretreatment of CF with anti-CF antisera inhibited production of NO2-. DV-stimulated spleen cell culture supernatants showed peak production of CF and NO2- at 72h. In DV-infected mouse spleen, maximum NO2- production occurred at 8-11 days post-infection, which correlated with peak cytotoxic activity in the spleen. Pretreatment of spleen cells with N(G)-monomethyl L-arginine (NMMA) inhibited NO2- production. NO2- production was abrogated in a dose-dependent manner by treatment of spleen cells with Ca2+ channel blocking drug, Nifedipine. The findings demonstrate that DV-induced CF induces production of NO2- in spleen cells, probably in a Ca2+-dependent manner, and may be a mechanism of target cell killing.
authors.affiliation: Postgraduate Department of Microbiology, K.G. Medical College, Lucknow, India.
authors.forename: A
authors.initials: A
authors.lastname: Misra
authors.forename: R
authors.initials: R
authors.lastname: Mukerjee
authors.forename: U C
authors.initials: UC
authors.lastname: Chaturvedi
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000276:immunology; D001402:B-Lymphocytes / Q000378:metabolism; D001681:Biological Assay; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003470:Culture Media / Q000032:analysis; D016207:Cytokines / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D003715:Dengue / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D009543:Nifedipine / Q000494:pharmacology; D009573:Nitrites / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000821:virology*; D013601:T-Lymphocytes / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D019138:Antibodies, Blocking; D003470:Culture Media; D016207:Cytokines; D009573:Nitrites; C087354:dengue-2 virus-induced cytotoxic factor; D019323:omega-N-Methylarginine; D009543:Nifedipine; D002118:Calcium