title: Expression of vFLIP in a lentiviral vaccine vector activates NF-{kappa}B, matures dendritic cells, and increases CD8+ T-cell responses.
abstract: Lentiviral vectors deliver antigens to dendritic cells (DCs) in vivo, but they do not trigger DC maturation. We therefore expressed a viral protein that constitutively activates NF-kappaB, vFLIP from Kaposi's sarcoma-associated herpesvirus (KSHV), in a lentivector to mature DCs. vFLIP activated NF-kappaB in mouse bone marrow-derived DCs in vitro and matured these DCs to a similar extent as lipopolysaccharide; costimulatory markers CD80, CD86, CD40, and ICAM-1 were upregulated and tumor necrosis factor alpha and interleukin-12 secreted. The vFLIP-expressing lentivector also matured DCs in vivo. When we coexpressed vFLIP in a lentivector with ovalbumin (Ova), we found an increased immune response to Ova; up to 10 times more Ova-specific CD8(+) T cells secreting gamma interferon were detected in the spleens of vFLIP_Ova-immunized mice than in the spleens of mice immunized with GFP_Ova. Furthermore, this increased CD8(+) T-cell response correlated with improved tumor-free survival in a tumor therapy model. A single immunization with vFLIP_Ova also reduced the parasite load when mice were challenged with OVA-Leishmania donovani. In conclusion, vFLIP from KSHV is a DC activator, maturing DCs in vitro and in vivo. This demonstrates that NF-kappaB activation is sufficient to induce many aspects of DC maturation and that expression of a constitutive NF-kappaB activator can improve the efficacy of a vaccine vector.
authors.affiliation: MRC Centre for Medical Molecular Virology, University College London, United Kingdom.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Rowe
authors.forename: Luciene
authors.initials: L
authors.lastname: Lopes
authors.forename: Najmeeyah
authors.initials: N
authors.lastname: Brown
authors.forename: Sofia
authors.initials: S
authors.lastname: Efklidou
authors.forename: Timothy
authors.initials: T
authors.lastname: Smallie
authors.forename: Sarah
authors.initials: S
authors.lastname: Karrar
authors.forename: Paul M
authors.initials: PM
authors.lastname: Kaye
authors.forename: Mary K
authors.initials: MK
authors.lastname: Collins
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000821:virology*; D007893:Leishmania donovani / Q000276:immunology; D007896:Leishmaniasis / Q000517:prevention & control; D016086:Lentivirus / Q000235:genetics* / Q000276:immunology; D051379:Mice; D016328:NF-kappa B / Q000096:biosynthesis*; D009369:Neoplasms / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D011971:Receptors, Immunologic / Q000096:biosynthesis; D013154:Spleen / Q000276:immunology; D016019:Survival Analysis; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000235:genetics* / Q000276:immunology
chemical_list: D019496:Cancer Vaccines; D016207:Cytokines; D016328:NF-kappa B; D011971:Receptors, Immunologic; D014764:Viral Proteins; D014765:Viral Vaccines; C481275:viral FLIP protein, Human herpesvirus 8; D010047:Ovalbumin