title: Murine granulocyte-macrophage colony-stimulating factor expressed from a bicistronic simian immunodeficiency virus-based integrase-defective lentiviral vector does not enhance T-cell responses in mice.
abstract: As a prelude to immunization studies in nonhuman primates, we compared in mice the immunogenicity of a simian immunodeficiency virus (SIV)-based integrase (IN)-defective lentiviral vector (IDLV) encoding the model antigen-enhanced green fluorescence protein (eGFP) in the presence or absence of the murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) expressed from an internal ribosomal entry site (IRES) sequence. BALB/c mice were immunized once intramuscularly with IDLV expressing eGFP alone or eGFP and mGM-CSF and immune responses were evaluated up to 90 days from the single intramuscular immunization. Results indicated that the mGM-CSF was unable to improve the magnitude and quality of the immune response against the eGFP transgene in the context of the SIV-based IDLV, as evaluated by enzyme-linked immunosorbent spot (ELISPOT) assays for interferon-γ (IFN-γ) and by intracellular cytokine staining for IFN-γ, interleukin-2 (IL-2), and tumor necrosis factor-alpha (TNF-α). These findings suggest that for vaccination purposes, the presence of mGM-CSF expressed after the IRES in a SIV-based IDLV system does not favor the improvement of the immunological response against the transgene of interest. Further studies should investigate whether the selection of a different cytokine gene might improve the immune response against the transgene.
authors.affiliation: 1 Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità , Rome, Italy .
authors.forename: Zuleika
authors.initials: Z
authors.lastname: Michelini
authors.forename: Donatella
authors.initials: D
authors.lastname: Negri
authors.forename: Mirella
authors.initials: M
authors.lastname: Biava
authors.forename: Silvia
authors.initials: S
authors.lastname: Baroncelli
authors.forename: Massimo
authors.initials: M
authors.lastname: Spada
authors.forename: Pasqualina
authors.initials: P
authors.lastname: Leone
authors.forename: Roberta
authors.initials: R
authors.lastname: Bona
authors.forename: Maria
authors.initials: M
authors.lastname: Blasi
authors.forename: Didier
authors.initials: D
authors.lastname: Nègre
authors.forename: Mary E
authors.initials: ME
authors.lastname: Klotman
authors.forename: Andrea
authors.initials: A
authors.lastname: Cara
mesh_terms: D000818:Animals; D004337:Drug Carriers; D058501:Enzyme-Linked Immunospot Assay; D005260:Female; D015870:Gene Expression; D005822:Genetic Vectors; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000276:immunology; D007273:Injections, Intramuscular; D019426:Integrases / Q000172:deficiency; D007371:Interferon-gamma / Q000032:analysis; D007376:Interleukin-2 / Q000032:analysis; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015302:Simian Immunodeficiency Virus / Q000201:enzymology / Q000235:genetics*; D013194:Staining and Labeling; D013601:T-Lymphocytes / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D004337:Drug Carriers; D007376:Interleukin-2; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D019426:Integrases