Inactivated Orf-virus shows disease modifying antiviral activity in a guinea pig model of genital herpesvirus infection.

BACKGROUND: Inactivated Orf virus (iORFV) has been used as a preventative as well as a therapeutic immunomodulator in veterinary medicine in different species. iORFV elicits strong effects on cytokine secretion in mice and human immune cells leading to an auto-regulated loop of initial up-regulation of inflammatory and Th1-related cytokines followed by Th2-related cytokines that attenuate immunopathology. The therapeutic potential of iORFV has been recognized in several models for difficult-to-treat disease areas such as chronic viral diseases, liver fibrosis or various forms of cancer. METHODS: Guinea pigs were infected with Human Herpesvirus (HSV)-2 strain MS and treated with iORFV, Acyclovir (ACV) or placebo, respectively. Clinical score of herpes lesions and viral shedding was assessed over a period of 40 days. In addition, viral DNA in dorsal root ganglia was quantified at the end of the study. RESULTS: Disease symptoms were minimal or absent in iORFV-treated guinea pigs but tended to be severe in animals treated with either ACV or placebo. The cumulated disease score was significantly reduced in iORFV-treated but not in ACV- or placebo-treated guinea pigs. In addition, treatment with iORFV, but not ACV or placebo, led to significant reduction of viral DNA load in dorsal root ganglia. CONCLUSION: iORFV effectively suppressed recurrences in guinea pigs experimentally infected with HSV. iORFV did not only reduce recurrent disease episodes but was, compared with ACV, more effective in reducing latency as measured by viral DNA detected in dorsal root ganglia of infected animals.

Inactivated ORF virus shows antifibrotic activity and inhibits human hepatitis B virus (HBV) and hepatitis C virus (HCV) replication in preclinical models.

Inactivated orf virus (iORFV), strain D1701, is a potent immune modulator in various animal species. We recently demonstrated that iORFV induces strong antiviral activity in animal models of acute and chronic viral infections. In addition, we found D1701-mediated antifibrotic effects in different rat models of liver fibrosis. In the present study, we compare iORFV derived from two different strains of ORFV, D1701 and NZ2, respectively, with respect to their antifibrotic potential as well as their potential to induce an antiviral response controlling infections with the hepatotropic pathogens hepatitis C virus (HCV) and hepatitis B virus (HBV). Both strains of ORFV showed anti-viral activity against HCV in vitro and against HBV in a transgenic mouse model without signs of necro-inflammation in vivo. Our experiments suggest that the absence of liver damage is potentially mediated by iORFV-induced downregulation of antigen cross-presentation in liver sinus endothelial cells. Furthermore, both strains showed significant anti-fibrotic activity in rat models of liver fibrosis. iORFV strain NZ2 appeared more potent compared to strain D1701 with respect to both its antiviral and antifibrotic activity on the basis of dosages estimated by titration of active virus. These results show a potential therapeutic approach against two important human liver pathogens HBV and HCV that independently addresses concomitant liver fibrosis. Further studies are required to characterize the details of the mechanisms involved in this novel therapeutic principle.

Inactivated Orf virus (Parapoxvirus ovis) elicits antifibrotic activity in models of liver fibrosis.

AIM: Inactivated Orf virus (ORFV, Parapoxvirus ovis) demonstrates strong antiviral activity in animal models including a human hepatitis B virus (HBV)-transgenic mouse. In addition, expression of interferon (IFN)-γ and interleukin-10 (IL-10) was induced after administration of inactivated ORFV in these mice. IFN-γ and IL-10 are known to elicit antifibrotic activity. We therefore aimed to study antifibrotic activity of inactivated ORFV in models of liver fibrosis. METHODS: We characterized ORFV-induced hepatic cytokine expression in rats. We then studied ORFV in two models of liver fibrosis in rats, pig serum-induced liver fibrosis and carbon tetrachloride (CCL4 )-induced liver fibrosis. RESULTS: ORFV induced hepatic expression of IFN-γ and IL-10 in rats. ORFV mediated antifibrotic activity when administrated concomitantly with the fibrosis-inducing agents in both models of liver fibrosis. Importantly, when CCL4 -induced liver fibrosis was already established, ORFV application still showed significant antifibrotic activity. In addition, we were able to demonstrate a direct antifibrotic effect of ORFV on stellate cells. CONCLUSION: These results establish a potential novel antifibrotic therapeutic approach that not only prevents but also resolves established liver fibrosis. Further studies are required to unravel the details of the mechanisms involved.

Inactivated orf virus (Parapoxvirus ovis) induces antitumoral activity in transplantable tumor models.

Orf virus (ORFV, Parapoxvirus ovis) possesses strong immunomodulating activity including the induction of interferon gamma (IFN-γ) and interleukin-12 (IL-12) expression. Antiviral effects have been described which appeared to be facilitated by an ORFV-induced Type 1 helper T-cell (Th1-type) immune response. In this study, we investigated the potential antitumoral activity of inactivated ORFV in transplantable tumor models. We show that parenteral administration of inactivated ORFV mediates antitumor effects in various models including the murine syngenic B16 F10 melanoma and MDA-MB-231 human breast cancer xenograft. Inhibition of natural killer (NK) and NKT cell activity through administration of an anti-mouse NK-1.1 antibody led to a reduction of ORFV-mediated antitumoral effects. However, residual antitumoral activity was observed. This observation was confirmed in MDA-MB-231 tumor-bearing NOD/LtSz-scid/j mice which not only lack functional T and B lymphocytes but, in addition, have virtually no cells positive for the NK 1.1 cell surface marker. Thus, administration of inactivated ORFV induced inhibitory effects on the growth of transplantable tumors even under conditions of severe immunosuppression.

Characterization of immunostimulatory components of orf virus (parapoxvirus ovis).

Inactivated orf virus (ORFV, parapoxvirus ovis) induces antiviral activity in animal models of acute and chronic viral infections and exerts strong effects on human immune cells. ORFV activates antigen presenting cells (APC) via CD14 and, probably, Toll-like receptor signalling, and triggers the release of IFN-γ that has been identified as the key mediator of the antiviral activity. After delineating virus proteins as being the most likely active constituent, we aimed to characterize the ORFV proteins responsible for the therapeutic effect. By using a vaccinia virus/ORFV expression library we identified several multi-gene DNA fragments with strong immunomodulatory activity. Together these fragments contain 27 ORFs. The encoded proteins are related to virion structure and transcription but are otherwise unrelated. Two proteins were separately expressed and purified, and demonstrated immunostimulatory activity. Gene expression profiles induced by ORFV and the identified fragments were investigated by microarray analysis. Interestingly, all active fragments induced a similar gene-expression pattern, differing only in quantitative aspects. Obviously, several proteins of ORFV activate similar cellular pathways, modulating APC to generate a strong T-helper 1-dominated immune response. This was balanced by additional induction of immune dampening mechanisms, suggesting regulatory differences compared to single cytokine therapies. We conclude that ORFV may have the potential to enrich the armamentarium of antiviral therapies.

Variable sensitivity to noxious heat is mediated by differential expression of the CGRP gene.

Heat sensitivity shows considerable functional variability in humans and laboratory animals, and is fundamental to inflammatory and possibly neuropathic pain. In the mouse, at least, much of this variability is genetic because inbred strains differ robustly in their behavioral sensitivity to noxious heat. These strain differences are shown here to reflect differential responsiveness of primary afferent thermal nociceptors to heat stimuli. We further present convergent behavioral and electrophysiological evidence that the variable responses to noxious heat are due to strain-dependence of CGRP expression and sensitivity. Strain differences in behavioral response to noxious heat could be abolished by peripheral injection of CGRP, blockade of cutaneous and spinal CGRP receptors, or long-term inactivation of CGRP with a CGRP-binding Spiegelmer. Linkage mapping supports the contention that the genetic variant determining variable heat pain sensitivity across mouse strains affects the expression of the Calca gene that codes for CGRPalpha.

Expression of cytokine mRNA and protein in joints and lymphoid organs during the course of rat antigen-induced arthritis.

Cytokine expression was assessed during antigen-induced arthritis (AIA) in synovial membrane (SM), inguinal lymph node (LN), and spleen using competitive RT-PCR and sandwich ELISA. In the SM, early elevations of IL-1beta and IL-6 mRNA (by 6 hours; 450- and 200-fold, respectively) correlated with the joint swelling; a 6-fold increase in tumor necrosis factor alpha (TNFalpha) was not significant. Not only IL-2 and IFN-gamma (which increased 10,000-fold and 200-fold, respectively), but also IL-5 and IL-10, increased acutely (6 hours - day 1; 3-fold and 35-fold, respectively) in the SM. In general, the protein levels in the SM for IL-1beta, IL-6, TNFalpha, IFN-gamma, IL-4, and IL-10 (increase from 4-fold to 15-fold) matched the course of mRNA expression. In the inguinal LN, there were early mRNA elevations of IL-6 (a 2.5-fold increase by 6 hours, which correlated positively with the joint swelling) and IL-2 (4-fold by 6 hours), as well as later rises of IL-4 and IL-5 (2.5- and 4-fold, respectively, by day 3). No significant elevations of the corresponding proteins in this tissue were observed, except for IL-1beta (by day 6) and IL-10 (by day 1). In the spleen, there were significant mRNA elevations at 6 hours of IL-1beta (1.5-fold), IL-6 (4-fold; positively correlated with the joint swelling), IFN-gamma (3-fold), and IL-2 (7- to 10-fold). IL-5 and IL-10 (2- and 3-fold, respectively) peaked from 6 hours to day 3 in the spleen. Increases of the corresponding proteins were significant in comparison with day 0 only in the case of IL-2 (day 6). By day 6 (transition to the chronic phase), the mRNA for cytokines declined to or below prearthritis levels in all the tissues studied except for IL-1beta in the SM and IL-6 in the spleen. AIA is thus characterized by four phenomena: early synovial activation of macrophages, T helper (Th)1-like, and Th2-like cells; late, well-segregated Th2-like responses in the inguinal LN; late, overlapping Th1-like/Th2-like peaks in the spleen; and chronic elevation of synovial IL-1beta mRNA and spleen IL-6 mRNA.

Immunomodulatory effects of inactivated parapoxvirus ovis (ORF virus) on human peripheral immune cells: induction of cytokine secretion in monocytes and Th1-like cells.

Inactivated parapoxvirus ovis (Orf virus; PPVO) recently displayed strong immunostimulating and modulating capacities in several animal models for acute and chronic virus infections through the induction of gamma interferon (IFN-gamma) as a key mediator of antiviral activity. The data presented in this work demonstrate that inactivated PPVO has strong effects on cytokine secretion by human immune cells, including the upregulation of inflammatory and Th1-related cytokines (IFN-gamma, tumor necrosis factor alpha [TNF-alpha], interleukin 6 [IL-6], IL-8, IL-12, and IL-18) as well as anti-inflammatory and Th2-related cytokines (IL-4, IL-10, and IL-1 receptor antagonist [IL-1ra]). Studies on the mechanism of action revealed virus particles to be the effective components of the preparation. The virus particles activate monocytes or other antigen-presenting cells (APC), e.g., plasmacytoid dendritic cells, through signaling over CD14 and a Toll-like receptor and the intracellular presence of certain PPVO-specific components. The activation of monocytes or APC is followed by the release of early proinflammatory cytokines (TNF-alpha, IL-6, and IL-8) as well as the Th1-related cytokines IL-12 and IL-18. Both IL-18 and IL-12 are involved in PPVO-mediated IFN-gamma release by T cells and/or NK cells. The proinflammatory response is accompanied by the induction of anti-inflammatory and Th2-related cytokines (IL-4, IL-10, and IL-1ra), which exert a limiting efffect on the inflammatory response induced by PPVO. We conclude that the induction of a natural immune response with physiologically significant amounts of different cytokines and with antiviral potential might provide advantages over existing antiviral immunotherapies.

Inactivated parapoxvirus ovis (Orf virus) has antiviral activity against hepatitis B virus and herpes simplex virus.

It is known that some viruses are able to induce vigorous immune reactions. This study shows that inactivated parapoxvirus ovis (Orf virus), strain D1701 (PPVO), induces an autoregulatory cytokine response that involves the upregulation of IL-12, IL-18, IFN-gamma and other T helper 1-type cytokines and their subsequent downregulation, which is accompanied by induction of IL-4. An increase in IL-10 expression was also found in the livers of PPVO-treated mice. PPVO protects mice from lethal herpes simplex virus type 1 infection and guinea pigs from recurrent genital herpes disease. With dosages as low as 500 000 virus particles, PPVO is more potent than the current standard 3TC therapy in hepatitis B virus transgenic mice. No signs of inflammation or any other side effects were observed. PPVO induces IL-12, TNF-alpha and, together with a suboptimal concentration of Concanavalin A, IFN-gamma in human peripheral blood leukocytes as well. The principle of an autoregulatory cytokine induction by an inactivated virus might have advantages over existing immune therapies and it is concluded that inactivated PPVO should be investigated further for its potential use in antiviral therapy.

Pharmacological sensitivity and gene expression analysis of the tibial nerve injury model of neuropathic pain.

The tibial nerve injury model is a novel, surgically uncomplicated, rat model of neuropathic pain based on a unilateral transection (neurotomy) of the tibial branch of the sciatic nerve. The aim of the present study was to describe some behavioral and molecular features of the model, and to test its sensitivity to a number of drugs which are currently used for the treatment of neuropathic pain. The model was characterized by a pronounced mechanical allodynia which was present in all subjects and a less robust thermal hyperalgesia. Mechanical allodynia developed within 2 weeks post-surgery and was reliably present for at least 9 weeks. Neurotomized rats showed no autotomy and their body weight developed normally. Gene expression in ipsilateral L5 dorsal root ganglia, analyzed by quantitative polymerase chain reaction (PCR), showed a pronounced up-regulation of galanin and vasointestinal peptide (VIP). This up-regulation developed rapidly (within 1 to 2 days following neurotomy) and remained present for at least 12 days. On the other hand, expression of calcitonin gene-related peptide (CGRP) and substance P mRNA was down-regulated 12 days following neurotomy. Mechanical allodynia was completely reversed by morphine [minimal effective dose (MED): 8 mg/kg, i.p.] and partially reversed by carbamazepine (MED: 64 mg/kg, i.p.), baclofen (MED: 3 mg/kg, i.p.) and amitriptyline (trend for efficacy at 32 mg/kg, i.p.), but not by gabapentin (50-100 mg/kg, i.p.). The finding that the tibial nerve injury model shows a robust and persistent mechanical allodynia which is sensitive to a number of established analgesics, as well as a gene expression profile which is compatible with that obtained in other models of neuropathic pain, further supports its validity as a reliable and surgically uncomplicated model for the study of neuropathic pain.