title: Host's innate immune response to fungal and bacterial agents in vitro: up-regulation of interleukin-15 gene expression resulting in enhanced natural killer cell activity.
abstract: Natural killer (NK) cells play an important role in the first line of defence against viral infections. We have shown earlier that exposure of human peripheral blood mononuclear cells (PBMC) to viruses results in rapid up-regulation of NK cell activity via interleukin-15 (IL-15) induction, and that this mechanism curtails viral infection in vitro. By using Candida albicans, Escherichia coli and Staphylococcus aureus, we now show here that exposure of PBMC to fungi and bacteria also results in an immediate increase of NK cytotoxicity. Reverse transcriptase-polymerase chain reaction and Western blot analyses as well as the use of antibodies against different cytokines revealed that IL-15 induction played a predominant role in this NK activation. These results indicate that IL-15 is also involved in the innate immune response against fungal and bacterial agents.
authors.affiliation: Department of Microbiology & Immunology, and Pediatric Research Center, University of Montreal and Sainte-Justine Hospital, Montreal, Canada.
authors.forename: Phay
authors.initials: P
authors.lastname: Tran
authors.forename: Rasheed
authors.initials: R
authors.lastname: Ahmad
authors.forename: Jingwu
authors.initials: J
authors.lastname: Xu
authors.forename: Ali
authors.initials: A
authors.lastname: Ahmad
authors.forename: José
authors.initials: J
authors.lastname: Menezes
mesh_terms: D001419:Bacteria / Q000276:immunology*; D002176:Candida albicans / Q000276:immunology*; D002460:Cell Line; D016207:Cytokines / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology; D015654:Herpesvirus 6, Human / Q000276:immunology; D006801:Humans; D019409:Interleukin-15 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013211:Staphylococcus aureus / Q000276:immunology; D015854:Up-Regulation / Q000276:immunology
chemical_list: D016207:Cytokines; D019409:Interleukin-15; D012333:RNA, Messenger