Arnt-Ove Hovden

University of Bergen, Bergen, Hordaland, Norway

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Publications (11)18.91 Total impact

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    Florian Sprater, Arnt-Ove Hovden, Silke Appel
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    ABSTRACT: Dendritic cells (DC) are the only hematopoietic cells expressing the epithelial specific Ets transcription factor ESE-3. Here we analyzed presence and quantity of isoforms ESE-3a, ESE-3b and ESE-3j in various immunogenic and tolerogenic human monocyte-derived DC (moDC) and blood DC populations using quantitative real time PCR and immunoblot analyses. ESE-3a and ESE-3b were detectable in all moDC populations with ESE-3b being the main transcript. ESE-3b expression was upregulated in immunogenic moDC and downregulated in tolerogenic moDC compared to immature moDC. ESE-3a had similar transcript levels in immature and immunogenic moDC and had very low levels in tolerogenic moDC. In blood DC populations only splice variant ESE-3b was detectable. ESE-3j was not detectable in any of the DC populations. These findings suggest that ESE-3b is the functionally most important ESE-3 isoform in DC.
    PLoS ONE 01/2012; 7(11):e49577. · 3.53 Impact Factor
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    ABSTRACT: Dendritic cells (DC) used in therapeutic cancer immunotherapy have to be able to stimulate T cells resulting in an immune response that can efficiently target the cancer cells. One of the critical hurdles has been the lack of IL-12p70 production when maturating the DC, which is rectified by using the bacterial preparation OK432 (trade name Picibanil) to mature the cells. In order to identify the mechanism behind OK432 stimulation of DC, we investigated the contribution of different TLR to examine their involvement in IL-12p70 production. By combining different inhibitors of TLR signaling, we demonstrate here that TLR3 is responsible for the IL-12p70 production of DC induced by OK432. Moreover, our data suggest that the ligand triggering IL-12p70 secretion upon TLR3 stimulation is sensitive to proteinase and partly also RNAse treatment. The fact that a bacterial compound like OK432 can activate the TLR3 pathway in human DC is a novel finding. OK432 demonstrates a critical ability to induce IL-12p70 production, which is of great relevance in DC based cancer immunotherapy.
    PLoS ONE 01/2012; 7(2):e31217. · 3.53 Impact Factor
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    ABSTRACT: Design of tumour specific immunotherapies using the patients' own dendritic cells (DC) is a fast advancing scientific field. The functional qualities of the DC generated in vitro are critical, and today's gold standard for maturation is a cytokine cocktail consisting of IL-1β, IL-6, TNF-α and PGE2 generating cells lacking IL-12p70 production. OK432 is an immunotherapeutic agent derived from killed Streptococcus pyogenes that has been used clinically to treat malignant and benign neoplasms for decades. In this study, we analysed the effects of OK432 on DC maturation, DC migration, cytokine and chemokine secretion as well as T-cell stimulatory capacity, and compared it to the cytokine cocktail alone and combinations of OK432 with the cytokine cocktail. OK432 induced a marked up-regulation of CD40 on the cell surface as well as a strong inflammatory response from the DC with significantly more secretion of 19 different cytokines and chemokines compared to the cytokine cocktail. Interestingly, secretion of IL-15 and IL-12p70 was detected at high concentrations after maturation of DC with OK432. However, the OK432 treated DC did not migrate as well as DC treated with cytokine cocktail in a transwell migration assay. During allogeneic T-cell stimulation OK432 treated DC induced proliferation of over 50 percent of CD4 and 30 percent of CD8 T-cells for more than two cell divisions, whereas cytokine cocktail treated DC induced proliferation of 12 and 11 percent of CD4 and CD8 T-cells, respectively. The clinically approved compound OK432 has interesting properties that warrants its use in DC immunotherapy and should be considered as a potential immunomodulating agent in cancer immunotherapy.
    BMC Immunology 01/2011; 12:2. · 2.61 Impact Factor
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    ABSTRACT: Dendritic cells (DC) are a heterogeneous group of professional antigen-presenting cells (APC) involved in both initiating immune responses and maintaining tolerance. Roughly, DC can be divided into plasmacytoid DC (pDC) and conventional DC (cDC). By controlling regulatory T cells (Treg), DC can influence the outcome of both immunity and autoimmunity. Since the use of mice as in vivo models became a practical tool for researchers studying pathological events in all kind of human diseases, we decided to compare levels of cDC, pDC and Treg in both spleen and blood between two inbred mouse strains. Here we show that two commonly used mouse strains, BALB/c and C57BL/10J mice, have significantly different levels of distinct CD11c(+)/CD4(-)/CD8a(+), CD11c(+)/CD4(+)/CD8a(-) and CD11c(+)/CD4(-)/CD8a(-) cDC populations, pDC and Treg. Therefore, we emphasize the importance of considering the proper model when comparing data sets from different mouse strains.
    Scandinavian Journal of Immunology 12/2009; 70(6):541-6. · 2.20 Impact Factor
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    ABSTRACT: Highly pathogenic avian influenza (HPAI) outbreaks in domestic poultry bring humans into close contact with new influenza subtypes and represent a threat to human health. In 1999, an HPAI outbreak of H7N1 virus occurred in domestic poultry in Italy, and a wild-type virus isolate from this outbreak was chosen as a pandemic vaccine candidate. We conducted a pilot study to investigate the kinetics of the humoral immune response induced after immunisation with an egg grown whole inactivated H7N1 virus vaccine in BALB/c mice. Mice were vaccinated with one or two doses of H7N1 vaccine (15 microg total protein) to investigate the influenza specific antibody secreting cell (IS-ASC) and serum antibody responses. After the first dose of vaccine, only IgM IS-ASC were detected in the spleen and bone marrow, whereas IgG, IgA and IgM IS-ASC were found after the second dose. Low antibody titres were detected after the first immunisation, whilst the second dose of vaccine significantly boosted the HI (range 128-512), neutralising and IgG antibody titres. The IgG subclass response was dominated by IgG2a indicating a dominant Th1 response after the first vaccination, whereas a more mixed Th1/Th2 profile was observed after the second dose. This pilot study shows the value of using a number of immunological methods to evaluate the quality of the immune response to potential pandemic candidate vaccines.
    Influenza and Other Respiratory Viruses 02/2009; 3(1):21-8. · 1.47 Impact Factor
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    ABSTRACT: Influenza is a major respiratory pathogen, which exerts a huge human and economic toll on society. Influenza is a vaccine preventable disease, however, the vaccine strains must be annually updated due to the continuous antigenic changes in the virus. Inactivated influenza vaccines have been used for over 50 years and have an excellent safety record. Annual vaccination is therefore recommended for all individuals with serious medical conditions, like COPD, and protects the vaccinee against influenza illness and also against hospitalization and death. In COPD patients, influenza infection can lead to exacerbations resulting in reduced quality of life, hospitalization and death in the most severe cases. Although there is only limited literature on the use of influenza vaccination solely in COPD patients, there is clearly enough evidence to recommend annual vaccination in this group. This review will focus on influenza virus and prophylaxis with inactivated influenza vaccines in COPD patients and other "at risk" groups to reduce morbidity, save lives, and reduce health care costs.
    International Journal of COPD 02/2007; 2(3):229-40.
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    ABSTRACT: Recently the urgency of developing a pandemic influenza vaccine has lead to the re-evaluation of the use of whole virus vaccine. We have compared the humoral immune response and the protective efficacy of whole and split influenza virus vaccines in mice. Whole virus vaccine was more immunogenic particularly after the first dose of vaccine, generally eliciting higher numbers of systemic antibody secreting cells and an earlier and higher neutralising antibody response. Immunisation with one dose of whole virus vaccine more effectively reduced viral shedding upon non-lethal homologous viral challenge, but two doses of split virus vaccine was most effective at limiting viral replication and this was correlated with high influenza specific serum IgG concentrations. The two vaccine formulations induced different T helper profiles particularly after one dose of vaccine; split virus vaccine induced a type 2 bias response, whereas whole virus vaccine elicited a dominant type 1 response.
    Vaccine 12/2006; 24(44-46):6585-7. · 3.49 Impact Factor
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    ABSTRACT: Evaluation of new influenza vaccines, particularly when formulating a pandemic vaccine, requires extensive information on the humoral response to conventional vaccines. In this study, important information on the kinetics and magnitude of the immune response to monovalent vaccines are provided. BALB/c mice were immunised intramuscularly with one or two doses (7.5, 15 or 30 μg HA) of A/Panama/2007/99 (H3N2) split or whole virus vaccine at 3-week intervals. Mice were then sacrificed, and the class and IgG subclass of antibody-secreting cell (ASC) response was examined systemically in the spleen using the Enzyme-Linked ImmunoSpot Assay (ELISPOT). Sera were collected at the time of sacrifice and analysed by ELISA and haemagglutination inhibition (HI). A similar time course of response was observed to both types of vaccines with the peak in numbers of ASC observed in the spleen at 5–7 days after the first dose of vaccine and 3–5 days after the second dose of vaccine. Influenza-specific antibodies were detected at days 5–7 and increased up to 21 days and further increased 7–9 days after the second dose of vaccine. Interestingly, split virus vaccine induced both IgG1 and IgG2a, whereas whole virus vaccine induced mainly IgG2a antibody response. Further work will examine if this signals a Th1 profile.
    International Congress Series 01/2004; 1263:632-635.
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    ABSTRACT: Influenza vaccination is the main method of prophylaxis, but in a pandemic scenario vaccination will occur in an unprimed population. In this study we provide preliminary data on the kinetics of the immune response to a highly pathogenic avian H7N1 virus vaccine in mice. BALB/c mice were immunised intramuscularly with 1 or 2 doses (15 μg HA) of whole egg grown inactivated A/Chick/Italy/13474/99 H7N1 vaccine. Mice were sacrificed at 0, 3–7 and 21 days after each dose of vaccine. The Enzyme-Linked ImmunoSpot Assay (ELISPOT assay) was used to examine the class and IgG subclass of antibody secreting cell (ASC) response in the spleen and bone marrow. Sera were collected at the time of sacrifice and analysed by haemagglutination inhibition. In the spleen only IgM ASC were detected after first dose of vaccine whereas IgG, IgA and IgM were found after the second dose of vaccine. In our experience, this avian strain appears to be less immunogenic than whole H3N2 virus vaccine. Our data for this murine model confirm studies by others suggesting that a pandemic vaccine virus of avian origin may be considerably less immunogenic in man than the H1, H2 and H3 human subtypes.
    International Congress Series 01/2004; 1263:636-639.
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    Arnt-Ove Hovden, Maja A Sommerfelt
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    ABSTRACT: CD4 is the principal binding site for human and simian immunodeficiency virus (HIV/SIV) receptor interactions and the a chemokine receptor CXCR4 has been implicated as a primordial lentivirus receptor. This study sought to determine the relevance of CD4 and CXCR4 in virus-receptor interactions for the prototype lentivirus, maedi-visna virus (MVV) of sheep. Neither CD4 nor alpha/beta chemokine receptors represent principal receptors for MVV since human osteosarcoma cells devoid of these molecules were susceptible to productive infection. Interestingly, the presence of either CD4 and/or CXCR4 on indicator cells dramatically enhanced MVV-induced cell fusion (syncytium formation) for three independent virus strains. Syncytium formation results from virus-receptor interactions and can be inhibited by receptor ligands. However, neither SDF-la that binds CXCR4 nor recombinant gp120 (rgp120) that binds CD4 could specifically inhibit the observed enhancement of MVV-induced cell fusion under conditions that significantly reduced HIV-1-induced cell fusion. Our observations suggest that CD4 and CXCR4 may represent optional auxiliary components of an MVV receptor (or receptor complex) that facilitate MVV-mediated membrane fusion events, a feature important for virus entry. This potential accessory role for CXCR4 in MW receptor interactions may reflect the distant relationship between the ovine (MVV) and the human/feline lentiviruses (HIV/FIV).
    Apmis 11/2002; 110(10):697-708. · 2.07 Impact Factor
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    Arnt-Ove Hovden