Anti-Interferon-α monoclonal antibody, clone NU5

In this work we have tested the in vivo antiviral activity of type I interferons (IFNs) in Atlantic salmon by injecting presmolts intramuscularly (i.m.) with plasmids encoding IFNa1, IFNb or IFNc under the control of a CMV promoter, and measured expression of antiviral genes in organs and protection against infection with infectious salmon anemia virus (ISAV) infection. All three IFN plasmids induced expression of antiviral genes (Mx, Viperin, ISG15 and IFIT5) at the muscle injection site while the control plasmid had little effect. Only IFNb and IFNc plasmids induced expression of antiviral genes in head kidney, liver and heart. This suggests that IFNb and IFNc are distributed systemically while IFNa1 is active only at the injection site. Injection of IFNc plasmid was found to induce expression of antiviral genes and receptors for virus RNA (RIG-I, TLR3 and TLR7) in head kidney from 1 to at least 8 weeks. Immunoblotting showed increased expression of ISG15 and Mx protein in liver with time during this time period. Challenge of presmolts with ISAV 8 weeks after injection of IFN plasmids, showed strong protection of the IFNc plasmid injected fish, low protection of the IFNb plasmid injected fish and no protection of the IFNa1 plasmid injected fish. Clues to the difference in protection obtained with IFNb and IFNc plasmids were found by immunohistochemical and immunoblot studies of Mx protein, which indicated that IFNc plasmid stimulated stronger Mx protein expression in heart tissues and liver endothelial cells than IFNb plasmid. Taken together, these data suggest that i.m. injection of the IFNc expression plasmid may be a new method for protecting Atlantic salmon against virus infection. (C) 2014 The Authors. Published by Elsevier Ltd.

Introduction: IFNA1 (interferon alpha) is a key cytokine regulating the activity of numerous immune cells. Plasmacytoid dendritic cells (pDCs) as natural interferon-producing cells play critical roles as sensors of pathogens and link innate to adaptive immunity. CpG motifs within DNA sequences activating toll-like receptor 9 (TLR9) are the main stimuli eliciting IFNA1 secretion from pDCs. Adrenergic substances are capable of differentially modulating the response from various immune cells. Hence, the aim of this study was to examine how adrenoceptor stimulation influences TLR9-induced IFNA1 secretion from human pDCs. Methods: PBMCs generated from human whole blood and pDCs enriched from buffy coats were stimulated with LPS and CpG-ODN 2336 in the presence or absence of epinephrine and different adrenoceptor antagonists. Secretion of TNF and IFNA1 was measured by ELISA. Flow cytometry was used to determine efficacy of pDC enrichment and adrenoceptor expression of PBMC subsets. The influence of modified IFNA1 secretion on NK cell activity was evaluated using a colorimetric tumor cell lysis assay. Results: TLR9-induced IFNA1 secretion as well as TLR4-induced TNF secretion from PBMCs was dose-dependently attenuated by coincubation with epinephrine. Combination with different specific adrenoceptor antagonists revealed that this effect was mediated by the adrenoceptor b2 (ADRB2). Since flow cytometric analysis could exclude the presence of ADRB2 on pDCs, highly enriched pDCs lacked any visible impact of adrenoceptor stimulation on TLR9-induced IFNA1 release. Combination of pDCs with PBMCs restored the effect, even when they were separated by a permeable membrane. Suppression of TLR9-mediated IFNA1 secretion from PBMCs by adrenoceptor stimulation reduced the lytic activity of NK cells on K562 tumor cells. Conclusion: We provide insights into the underlying mechanisms of the interrelation between immune responses and pharmacological agents widely used in clinical practice. Our results have implications for the future treatment of human patients, in which the endogenous immune response plays a pivotal role, such as during viral infections, inflammatory diseases and cancers.