Bovine herpesvirus-1 infection in mouse neuroblastoma (Neuro-2A) cells.

Bovine herpesvirus 1 (BoHV-1) is an important cattle pathogen, that may cause rhinotracheitis, abortions and shipping fever. Virus establishes latency in sensory neurons, but periodically could reactivate. Recent studies identified mouse neuroblastoma (Neuro-2A) cells as a novel cell culture model to study factors that regulate BoHV-1 productive infection in neuronal cells. Herein, following BoHV-1 infection in Neuro-2A, a reduced cell viability occurred. Membrane damage and death morphological alterations, features of apoptosis and necrosis, were distinguished in infected cells. In addition, biochemical signs of apoptosis (caspase 3 activation and PARP cleavage) were observed. These results were accompanied by incomplete autophagy due to enhanced amounts of autophagic markers (LC3-II, ATG5 and Beclin 1), in the presence of increased levels of p62. Interestingly, protein expression of viral infected cell protein 0 (bICP0) was detected in Neuro-2A cells, although BoHV-1 inefficiently replicates in these cells, because just low levels of viral yield were found. Taken together, our results suggest that BoHV-1 may exert its potential neurotoxicity through a combined mechanism of necrosis and apoptosis. Moreover, incomplete autophagy occurred during BoHV-1 replication in Neuro-2A cells, which were favourable for viral persistence.

MG-132 reduces virus release in Bovine herpesvirus-1 infection.

Bovine herpesvirus 1 (BoHV-1) can provoke conjunctivitis, abortions and shipping fever. BoHV-1 infection can also cause immunosuppression and increased susceptibility to secondary bacterial infections, leading to pneumonia and occasionally to death. Herein, we investigated the influence of MG-132, a proteasome inhibitor, on BoHV-1 infection in bovine kidney (MDBK) cells. Infection of MDBK cells with BoHV-1 induces apoptotic cell death that enhances virus release. Whereas, MG-132 inhibited virus-induced apoptosis and stimulated autophagy. Protein expression of viral infected cell protein 0 (bICP0), which is constitutively expressed during infection and is able to stimulate Nuclear factor kappa B (NF-κB), was completely inhibited by MG-132. These results were accompanied by a significant delay in the NF-κB activation. Interestingly, the efficient virus release provoked by BoHV-1-induced apoptosis was significantly reduced by MG-132. Overall, this study suggests that MG-132, through the activation of autophagy, may limit BoHV-1 replication during productive infection, by providing an antiviral defense mechanism.

Clinical improvement in feline herpesvirus 1 infected cats by oral low dose of interleukin-12 plus interferon-gamma.

Feline herpesvirus 1 (FHV-1) is a widespread cat pathogen inducing rhinitis, conjunctivitis and corneal ulcers. To alleviate acute FHV-1-induced disease, antiviral agents are used often with antibiotics. But sometimes, these treatments, as well as conventional doses of cytokines have moderate efficacy and/or collateral effects. Herein we have investigated the effects of low dose interleukin (IL)-12 plus interferon (IFN)-gamma, prepared by Sequential Kinetic Activated (SKA), on the treatment of FHV-1 infection. Twenty-five, unvaccinated FHV-1-positive cats were recruited into a prospective, randomized, placebo-controlled, double-blinded clinical trial. Fifteen cats were treated for 6 months with oral low doses of SKA IL-12 plus IFN-gamma and 10 cats were treated with placebo. At 1, 6 and 12 months (follow-up) after the beginning of treatment, clinical assessment, PCR assay and blood count were carried out. At follow-up, in treated group, we observed significant (p<0.05) improvements in clinical signs and PCR became negative in 12/15 cats (80%). In placebo, 10/10 cats were PCR-positive, with improvements (30%) or worsening (70%) in clinical signs. Blood values were normal in both groups. Our results show that the low dose therapy, based on activated solutions of IL-12 plus IFN-gamma, represents a novel approach to treat FHV-1 infection in cats.

Modulation of telomerase activity, bTERT and c-Myc induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin during Bovine Herpesvirus 1 infection in MDBK cells.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) influences infection of kidney cells (MDBK) with Bovine Herpesvirus 1 (BHV-1) through an increase in virus replication and an acceleration of BHV-1-induced apoptosis. Previously our group demonstrated that BHV-1, in the early stages of infection, significantly up-regulates telomerase activity in MDBK cells, while, in the late phases of infection, when BHV-1-induced apoptosis occurred, a down-regulation of telomerase activity was detected. Hence, herein, for the first time, we described the influences of TCDD on telomerase activity during virus infection. In kidney cells (MDBK) infected with BHV-1 and exposed to different doses of TCDD we explored telomerase activity by TRAP assay. Concomitantly, we examined protein levels of both bTERT and c-Myc by Western blot analysis. In all groups, TCDD induced an acceleration in down-regulation of telomerase activity. Particularly, TCDD drastically and significantly decreased telomerase activity when virus-induced apoptosis took place. This result was accompanied from an accelerated down-regulation of bTERT and c-Myc. Finally, in the presence of TCDD, we evidenced a dose-dependent overexpression of aryl hydrocarbon receptor. Hence, our data suggest that TCDD, through a significant acceleration in down-regulation of telomerase activity, bTERT and c-Myc, may contribute to accelerated BHV-1-induced apoptosis.