title: Interleukin-7 enhances cell-mediated immune responses in vivo in an interleukin-2-dependent manner.
abstract: We have engineered recombinant vaccinia virus vectors expressing murine interleukin-7 (IL-7) in order to study the activity of this factor during virus infection. Virus-encoded IL-7 dramatically increased splenic cellularity in infected mice and enhanced the proliferative activity of T cells and their capacity to secrete IL-2 and IL-6, but not IFN-gamma, TNF-alpha or IL-4. Numbers of splenic CD4+ and CD8+ T lymphocytes were elevated two- to threefold. IL-7 also mediated a marked enhancement of both antigen-specific and nonspecific cellular immune activity. Total splenic antiviral cytotoxic T cells (CTL), natural killer (NK), and lymphokine-activated killer cells (LAK) responses were augmented significantly in mice given VV-HA-IL-7 compared with those given control virus, with accelerated clearance of the former. The enhanced antiviral cellular immune activity mediated by IL-7 was critically dependent on IL-2 produced by the host, but occurred independently of IFN-gamma. The ability of IL-7 to induce cellular immune responses in vivo may have applications in antiviral immunotherapy, particularly in cases of immunodeficiency.
authors.affiliation: Division of Immunology and Cell Biology, John Curtin School of Medical Research, Australian National University, Canberra, Australia.
authors.forename: K H
authors.initials: KH
authors.lastname: Leong
authors.forename: I A
authors.initials: IA
authors.lastname: Ramshaw
authors.forename: A J
authors.initials: AJ
authors.lastname: Ramsay
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002455:Cell Division; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D005822:Genetic Vectors; D007111:Immunity, Cellular / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology*; D015851:Interleukin-7 / Q000235:genetics / Q000276:immunology*; D007739:L Cells; D051379:Mice; D008808:Mice, Inbred CBA; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D014616:Vaccinia virus / Q000254:growth & development / Q000276:immunology
chemical_list: D016207:Cytokines; D007376:Interleukin-2; D015851:Interleukin-7; D011993:Recombinant Fusion Proteins