title: Bromelain activates murine macrophages and natural killer cells in vitro.
abstract: The innate immune response is critical for effective immunity against most pathogens. In this study, we show that bromelain, a mixture of cysteine proteases, can enhance IFN-gamma-mediated nitric oxide and TNFalpha production by macrophages. Bromelain's effect was independent of endotoxin receptor activation and was not caused by direct modulation of IFN-gamma receptors. Instead, bromelain either enhanced or acted synergistically with IFN-gamma receptor-mediated signals. These effects were seen in both RAW 264.7, a macrophage cell line, and primary macrophage populations. Bromelain also increased IL-2- and IL-12-mediated IFN-gamma production by NK cells. These results indicate a potential role for bromelain in the activation of inflammatory responses in situations where they may be deficient, such as may occur in immunocompromised individuals.
authors.affiliation: Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom.
authors.forename: C R
authors.initials: CR
authors.lastname: Engwerda
authors.forename: D
authors.initials: D
authors.lastname: Andrew
authors.forename: M
authors.initials: M
authors.lastname: Murphy
authors.forename: T L
authors.initials: TL
authors.lastname: Mynott
mesh_terms: D000818:Animals; D001963:Bromelains / Q000494:pharmacology*; D002460:Cell Line; D002478:Cells, Cultured; D004357:Drug Synergism; D005260:Female; D007371:Interferon-gamma / Q000378:metabolism / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000096:biosynthesis; D017471:Receptors, Interferon / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D000096743:Interferon gamma Receptor
chemical_list: D001963:Bromelains; D007371:Interferon-gamma; D009569:Nitric Oxide; D017471:Receptors, Interferon; D014409:Tumor Necrosis Factor-alpha; D000096743:Interferon gamma Receptor