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Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway is activated by myriad cytokines, which are involved in regulation of cell growth, proliferation, differentiation, apoptosis, angiogenesis, immunity and inflammatory response. Because of its significance in immune response, JAK-STAT pathway is often targeted by pathogens, including porcine reproductive and respiratory syndrome virus (PRRSV). PRRSV causes reproductive failure in sows and respiratory disease in pigs of all ages. A typical feature of the immune response to PRRSV infection in pigs is delayed production and low titer of virus neutralizing antibodies, and weak cell-mediated immune response. One of the possible reasons for the weak protective immune response is that PRRSV interferes with cytokine-mediated JAK-STAT signaling. PRRSV inhibits interferon-activated JAK-STAT signaling by blocking nuclear translocation of STAT1 and STAT2. The mechanism is that PRRSV non-structural protein 1β (nsp1β) induces degradation of karyopherin α1 (KPNA1), a critical adaptor in nucleo-cytoplasmic transport. PRRSV also antagonizes IL6-activated JAK-STAT3 signaling via inducing degradation of STAT3. In this review, we briefly introduce JAK-STAT signaling, summarize the PRRSV interference with it, and provide perspective on the perturbation in the context of PRRSV-elicited immune response. [ABSTRACT FROM AUTHOR]

A mixed ligand-nickel complex of formula [Ni(DBMA)(en)(H2O)3]·3H2O, where DBMA = 2,2-dibenzyl malonic acid, en = ethylenediamine, has been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The unit cell parameters for the complex area = 16.0214(16) Å,b = 10.0801(10) Å,c = 15.4024(15) Å,β = 108.488(2)°,V = 2359.074(40) Å3,Z = 4, space groupP2(1)/c. The crystal system of the complex is monoclinic. Thermal stability of the water cluster by thermogravimetric analysis has been studied. Gel electrophoresis assay demonstrated the ability of the complex to cleave pBR322 plasmid DNA. The binding of the complex with HeLa cell DNA (HC-DNA) has been investigated by fluorescence spectra. Value of IC50calculated for the complex shows that the complex exhibits good cytotoxicity against HeLa and KB cell lines. [ABSTRACT FROM AUTHOR]

Abstract: Kaposi''s sarcoma-associated herpesvirus (KSHV) is associated with Kaposi''s sarcoma and primary effusion lymphoma (PEL). The KSHV replication and transcription activator (RTA) and latency-associated nuclear antigen (LANA) play key roles in activating KSHV lytic replication and maintaining KSHV latency, respectively. Phosphorodiamidate morpholino oligomers (PMO) are similar to short single-stranded DNA oligomers, but possess a modified backbone that confers highly specific binding and resistance to nucleases. In this study, RTA and LANA mRNA in PEL cells were targeted by antisense peptide-conjugated PMO (P-PMO) in an effort to suppress KSHV replication. Highly efficient P-PMO uptake by PEL cells was observed. Treatment of PEL cells with a RTA P-PMO (RP1) reduced RTA expression in a dose-dependent and sequence-specific manner, and also caused a significant decrease in several KSHV early and late gene products, including vIL-6, vIRF-1, and ORF-K8.1A. KSHV viral DNA levels were reduced both in cells and culture supernatants of RP1 P-PMO-treated cells, indicating that KSHV lytic replication was suppressed. Treatment of BCBL-1 cells with P-PMO against LANA resulted in a reduction of LANA expression. Cell viability assays detected no cytotoxicity from P-PMO alone, within the concentration range used for the experiments in this study. These results suggest that RP1 P-PMO can specifically block KSHV replication, and further study is warranted. [Copyright &y& Elsevier]

Abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of a contagious disease characterized by reproductive failure in sows and respiratory disease in piglets. This infectious disease results in significant losses in the swine industry and specific anti-PRRSV drugs are needed. In this study, we evaluated a novel class of antisense compounds, peptide-conjugated phosphorodiamidate morpholino oligomers (P-PMOs), for their ability to suppress PRRSV replication in cell culture. P-PMOs are analogs of single-stranded DNA and contain a modified backbone that confers highly specific binding to RNA and resistance to nucleases. Of six P-PMOs tested, one (‘5UP1’), with sequence complementary to the 5′-terminal 21 nucleotides of the PRRSV genome, was found to be highly effective at reducing PRRSV replication in a specific and dose-dependent manner in CRL11171 cells in culture. 5UP1 treatment generated up to a 4.5log reduction in infectious PRRSV yield, while a control P-PMO had no effect on viral titer. Immunofluorescence assay with an anti-PRRSV monoclonal antibody confirmed the titer observations. The sequence-specificity of 5UP1 effect was confirmed in part by a cell-free luciferase reporter assay system, which showed that 5UP1-mediated inhibition of translation decreased if the target-RNA contained mispairings in relation to the 5UP1 P-PMO. Real-time RT-PCR showed that the production of PRRSV negative-sense RNA was reduced if 5UP1 was added to cells at up to 6h post-virus inoculation. Cell viability assays detected no cytotoxicity of 5UP1 within the concentration-range of this study. These results indicate that P-PMO 5UP1 has potential as an anti-PRRSV agent. [Copyright &y& Elsevier]

Kaposi's sarcoma–associated herpesvirus/human herpesvirus 8 (KSHV/HHV8) has been etiologically associated with several malignancies including Kaposi's sarcoma and primary effusion lymphoma. Oncogenic viral interferon regulatory factor (vIRF) encoded by KSHV ORF-K9 is a homologue of cellular interferon regulatory factor (IRF), and has been demonstrated to inhibit type I/II interferon signal transduction and transform NIH3T3 cells through the interactions with IRF-1, IRF-3, and CBP/p300 proteins. To counteract vIRF's pathogenic role, we have developed five ribozymes targeting ORF-K9 mRNA to suppress vIRF expression. The vIRF RNA substrates were cleaved up to 80% in a substrate-specific manner in transcript cleavage assays in vitro. In a transient transfection assay, two of the ribozymes efficiently suppressed the expression of vIRF protein measured by dual-color immunofluorescence assay that simultaneously detects the expression of both vIRF protein and ribozyme. Flow cytometry analysis showed that these ribozymes reduced vIRF expression up to 76%. A mutant ribozyme had no cleavage activity in vitro, but exhibited antisense effect in vivo. These results suggest that the ribozymes may provide a new approach for functional knockout of vIRF gene, and are potential candidates of antiviral therapy for KSHV-related malignancies. Cancer Gene Therapy (2001) 8, 285–293 [ABSTRACT FROM AUTHOR]

Viral interferon regulatory factor (vIRF) encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) inhibits the expression of interferon-responsive genes, causes cellular transformation and transactivates KSHV genes. In the present study, we characterized the mRNA expression pattern of the vIRF gene and its promoter. A vIRF transcript of 1.7 kb in size was detected in low level in uninduced KSHV-infected cells and its expression was inducible by 12-O-tetradecanoylphorbol-13-acetate (TPA), sensitive to cycloheximide and resistant to phosphonoacetic acid. The transcription start site was mapped to 79 nt upstream of the ATG initiation site by 5′-RACE. Mutagenesis analysis identified a region between -56 and the transcription start site (+1) as the minimal promoter region that contains a functional TATA box at -27. A region between -337 and -125 contains a repressor domain negated by sequence from -991 to -499 in BCBL-1 cells, a region which was also identified to be responsive to TPA induction. These results demonstrate vIRF as a KSHV early gene, identify its promoter and define the promoter regions that contain regulatory elements controlling vIRF transcription. Oncogene (2001) 20, 523–530. [ABSTRACT FROM AUTHOR]

Presents a study which examined genotypes of Kaposi's sarcoma (KS)-associated herpesvirus from patients with KS in Texas. Materials and methods; Results; Discussion.

Hepatitis E virus (HEV) is one of the causative agents for liver inflammation across the world. HEV is a positive-sense single-stranded RNA virus. Human HEV strains mainly belong to four major genotypes in the genus Orthohepevirus A, family Hepeviridae. Among the four genotypes, genotype 1 and 2 are obligate human pathogens, and genotype 3 and 4 cause zoonotic infections. HEV infection with genotype 1 and 2 mainly presents as acute and self-limiting hepatitis in young adults. However, HEV infection of pregnant women with genotype 1 strains can be exacerbated to fulminant hepatitis, resulting in a high rate of case fatality. As pregnant women maintain the balance of maternal-fetal tolerance and effective immunity against invading pathogens, HEV infection with genotype 1 might dysregulate the balance and cause the adverse outcome. Furthermore, HEV infection with genotype 3 can be chronic in immunocompromised patients, with rapid progression, which has been a challenge since it was reported years ago. The virus has a complex interaction with the host cells in downregulating antiviral factors and recruiting elements to generate a conducive environment of replication. The virus-cell interactions at an early stage might determine the consequence of the infection. In this review, advances in HEV virology, viral life cycle, viral interference with the immune response, and the pathogenesis in pregnant women are discussed, and perspectives on these aspects are presented. [ABSTRACT FROM AUTHOR]

Abstract Zika virus (ZIKV) is a mosquito-borne positive-sense single-stranded RNA virus in the family of Flaviviridae. Unlike other flaviviruses, ZIKV infection of pregnant women may result in birth defects in their newborns, such as microcephaly or vision problem. ZIKV is known to antagonize the interferon (IFN) production in infected cells. However, the exact mechanism of this interference is not fully understood. Here, we demonstrate that NS5 protein of ZIKV MR766 strain antagonizes IFN production through inhibiting the activation of TANK-binding kinase 1 (TBK1), which phosphorylates the transcription activator IFN regulatory factor 3 (IRF3). Mechanistically, NS5 interacts with the ubiquitin-like domain of TBK1 and results in less complex of TBK1 and TNF (tumor necrosis factor) receptor-associated factor 6 (TRAF6), leading to dampened TBK1 activation and IRF3 phosphorylation. Our study provides insights into the mechanism of ZIKV evasion of IFN-mediated innate immunity. Highlights • ZIKV NS5 antagonizes IFN production through inhibiting the activation of TBK1. • NS5 interacts with the ubiquitin-like domain of TBK1. • Both MT and RdRp domains of NS5 are needed for NS5 to interact with TBK1. • NS5 interaction with TBK1 leads to less TBK1 in complex with TRAF6. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome virus (PRRSV) causes inflammatory injuries in infected pigs. PRRSV induces secretion of high mobility group box 1 (HMGB1) that enhances inflammatory response. However, the mechanism of PRRSV-induced HMGB1 secretion is unknown. Here, we discovered PRRSV induced HMGB1 secretion via activating protein kinase C-delta (PKCδ). HMGB1 secretion was positively correlated with PKCδ activation in PRRSV-infected cells in a dose and time-dependent manner. Suppression of PKCδ with inhibitor and siRNA significantly blocked PRRSV-induced HMGB1 translocation and secretion, which indicates PKCδ activation is essential for the PRRSV-mediated HMGB1 secretion. In addition, PKCδ knockdown in PRRSV-infected cells led to downregulation of inflammatory cytokines, including IL-1beta and IL-6. Moreover, PRRSV E and pORF5a proteins were found to activate PKCδ and consequent HMGB1 secretion. These results demonstrate PRRSV activates PKCδ to induce HMGB1 secretion via E and pORF5a. This finding provides insights on the inflammatory response and pathogenesis of PRRSV infection. [ABSTRACT FROM AUTHOR]

Interferons (IFNs) are a group of secreted proteins that play critical roles in antiviral immunity, antitumor activity, activation of cytotoxic T cells, and modulation of host immune responses. IFNs are cytokines, and bind receptors on cell surfaces to trigger signal transduction. The major signaling pathway activated by IFNs is the JAK/STAT (Janus kinase/signal transducer and activator of transcription) pathway, a complex pathway involved in both viral and host survival strategies. On the one hand, viruses have evolved strategies to escape from antiviral host defenses evoked by IFN-activated JAK/STAT signaling. On the other hand, viruses have also evolved to exploit the JAK/STAT pathway to evoke activation of certain STATs that somehow promote viral pathogenesis. In this review, recent progress in our understanding of the virus-induced IFN-independent STAT signaling and its potential roles in viral induced inflammation and pathogenesis are summarized in detail, and perspectives are provided. [ABSTRACT FROM AUTHOR]

The interferon-induced double-strand RNA activated protein kinase (PKR) plays an important role in antiviral response. The objective of this study was to assess the effect of porcine reproductive and respiratory syndrome virus (PRRSV) on PKR activation. Here we report that PRRSV inhibited PKR activation during its early stage infection of primary pulmonary alveolar macrophages (PAMs). PRRSV infection led to lower level of phosphorylated PKR in comparison with mock-infected cells. The PKR inhibition was sustained until 10 h post infection in the presence of polyI:C, a synthetic analog of double-stranded RNA activating PKR. PKR-mediated phosphorylation of the eukaryotic translation initiation factor eIF2α was also lower in the PRRSV-infected PAMs during the early stage infection. Interestingly, inactivated PRRSV was capable to inhibit the PKR activation until 6 h post infection. This suggests that structural components of PRRSV virions were responsible for the inhibition, although PRRSV replication was needed for longer inhibition. These results indicate that the downregulation of PKR activation during early infection stage should be essential for PRRSV to avoid the antiviral response to initiate replication. This finding contributes to our understanding on PRRSV interaction with host innate immune response and reveal a target for control of PRRSV infection. [ABSTRACT FROM AUTHOR]

Hepatitis E virus (HEV) infection is a cause of hepatitis in humans worldwide and has been associated with a case-fatality rate of up to 30% in pregnant women. Recently, persistent and chronic HEV infections have been recognized as a serious clinical problem, especially in immunocompromised individuals. To date, there are no FDA-approved HEV-specific antiviral drugs. In this study, we evaluated antisense peptide-conjugated morpholino oligomers (PPMO) designed against HEV genomic sequences as potential HEV-specific antiviral compounds. Two genetically-distinct strains of human HEV, genotype 1 Sar55 and genotype 3 Kernow-C1, isolated from patients with acute and chronic hepatitis, respectively, were used to evaluate inhibition of viral replication by PPMO in liver cells. The anti-HEV PPMO produced a significant reduction in the levels of HEV RNA and capsid protein, indicating effective inhibition of HEV replication. PPMO HP1, which targets a highly conserved sequence in the start site region of ORF1, was also effective against the genotype 3 Kernow-C1 strain in stably-infected HepG2/C3A liver cells. The antiviral activity observed was specific, dose-responsive and potent, suggesting that further exploration of PPMO HP1 as a potential HEV-specific antiviral agent is warranted. [ABSTRACT FROM AUTHOR]

Highlights: [•] The interferon-inducing PRRSV strain A2MC2 elicited higher neutralizing antibodies. [•] A2MC2 induced earlier onset and higher levels of the antibodies than the MLV. [•] The A2MC2-induced antibodies were able to neutralize heterologous VR-2385. [•] A2MC2 induced higher expression of IFN-γ in PAMs than the MLV. [ABSTRACT FROM AUTHOR]

Abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-sense single-strand RNA virus that has contributed to substantial losses to the swine industry. The objective of this study was to examine the interference of interferon (IFN)-activated signaling by PRRSV viral proteins and compare the effects of several PRRSV strains on the IFN signaling. Three non-structural proteins (nsp 1β, 7 and 12) and two structural proteins (GP3 and N) of VR-2385 were found to significantly inhibit the expression of IFN-stimulated response element (ISRE) luciferase reporter. Nsp1β and N showed robust inhibition and their-encoding sequences from the six PRRSV strains (VR-2385, Ingelvac PRRS MLV, VR-2332, NVSL97-7895, MN184, and Lelystad) were cloned for further characterization. The nsp1βs of all the strains except MLV inhibited expression of IFN-induced ISRE reporter, interferon-stimulated gene 56 (ISG56) and signal transducer and activator of transcription 2 (STAT2). The N proteins inhibited the IFN-induced ISRE reporter expression and STAT2 elevation and blocked nuclear translocation of STAT1. In MARC-145 cells, all the six PRRSV strains with the exception of MN184 blocked the activity of exogenous IFN-α. In primary porcine pulmonary alveolar macrophages (PAMs), only MLV and NVSL failed to inhibit the activity of IFN-α. These results indicate that some PRRSV strains, such as NVSL and MN184, have variable effects on IFN-activated signaling in the two types of cells. [Copyright &y& Elsevier]

Abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) is known to interfere with the signaling of type I interferons (IFNs). Here we found PRRSV A2MC2 induced type I IFNs in cultured cells. A2MC2 replication in MARC-145 cells resulted in the synthesis of IFN-α2 protein, transcript elevation of the IFN-stimulated genes ISG15 and ISG56, and the proteins of the signal transducer and activator of transcription 2 (STAT2) and ISG56. A2MC2 infection of primary porcine pulmonary alveolar macrophages (PAMs) also led to the elevation of the two proteins, but had little cytopathic effect. Furthermore, A2MC2 infection of MARC-145 or PAM cells had no detectable inhibitory effect on the ability of IFN-α to induce an antiviral response. Sequencing analysis indicated that A2MC2 was closely related to VR-2332 and Ingelvac PRRS MLV with an identity of 99.8% at the nucleotide level. The identification of this IFN-inducing PRRSV isolate may be beneficial for vaccine development against PRRS. [Copyright &y& Elsevier]

Two manganese complexes, [Mn(L1)2(dibe)2](L1) (1) and [Mn(L2)2(dibe)2] (2) (where L1 = 2,2′-bipyridine (bipy), L2 = 1,10-phenanthroline (phen)), were synthesized by using a carboxylic acid ligand (dibe = 2,2-dibenzylmalonate acid). The two complexes were characterized using IR, elemental analysis, and X-ray crystallography. Fluorescence analysis indicates that the two complexes can bind to HeLa cell DNA (HC-DNA), and gel electrophoresis assay demonstrates the ability of the complexes to cleave the HC-DNA. The two complexes exhibit cytotoxic specificity and significant cancer cell inhibitory rate. Furthermore, apoptotic tests demonstrate that these two complexes have apoptotic effects on HeLa cells. [ABSTRACT FROM AUTHOR]

Abstract: Porcine reproductive and respiratory syndrome (PRRS) causes substantial economic losses to the swine industry in many countries, and current control strategies are inadequate. Previously, we explored the strategy of using peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) to inhibit PRRS virus (PRRSV) replication. PPMOs are nuclease-resistant and single-stranded DNA analogs containing a modified backbone conjugated to a cell-penetrating peptide and can act as antisense agents through steric blockade of complementary messenger RNA. A PPMO (designated 5UP2) targeting highly conserved sequence in the 5′-terminal region of the PRRSV genome was found to produce multi-log10 inhibition of PRRSV replication in cultured cells. To evaluate 5UP2 in vivo, we here administrated the PPMO to 3-week-old piglets via intranasal instillation at 24h before, and 2 and 24h after infection with PRRSV (strain VR2385). Blood samples were collected at 6, 10 and 14days post-infection (dpi) for detection of PRRSV RNA and antibodies. Necropsy was performed at 14dpi. Monitoring weight gain in all piglet groups throughout the experiment indicated that PPMO was well tolerated at the doses used. PPMO 5UP2 treatment significantly reduced PRRSV viremia at 6dpi. On day 14, piglets receiving 5UP2 had significantly less interstitial pneumonia and lower level of anti-PRRSV antibodies than untreated piglets. In alveolar macrophages isolated at the time of necropsy, the expression of antiviral genes in PPMO-treated piglets was elevated in comparison with untreated. This study provides further data indicating that the 5UP2 PPMO can be considered a candidate component for a novel PRRS control strategy. [Copyright &y& Elsevier]

Abstract: Porcine reproductive and respiratory syndrome (PRRS) has caused heavy economic losses in the swine industry worldwide and current strategies to control PRRS are inadequate. Previous studies have shown that peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) can be an effective antiviral against the PRRS virus (PRRSV). PPMO is structurally similar to DNA with modified backbone and is resistant to nuclease. This study was designed to examine increasing inhibitory effect of PPMO combination. Two pairs of PPMOs were identified to have enhanced suppression of PRRSV replication in cell culture, while individual constituents did not work under the same testing conditions. PPMO 5UP1 that is complementary to 5′ terminus of PRRSV genome was paired with 4P1 or 7P1 that are complementary to sequence in the translation initiation regions of ORFs 4 and 7, respectively. The PPMO combination also inhibited replication of heterologous strains in the North American PRRSV genotype. Treatment of the cells with the combinations reduced PRRSV RNA and protein levels. In cell-free or cell-based luciferase reporter assays, the PPMO combination suppressed target mRNA translation more effectively than individual constituents, indicating that the suppression was due to their antisense effect. These results suggest potential application of these PPMO combinations for PRRS control. [Copyright &y& Elsevier]

Abstract: Porcine reproductive and respiratory syndrome (PRRS) has been devastating the global swine industry for more than a decade, and current strategies to control PRRS are inadequate. In this study we characterized the inhibition of PRRS virus (PRRSV) replication by antisense phosphorodiamidate morpholino oligomers (PMO). Of 12 peptide-conjugated PMO (PPMO), four were found to be highly effective at inhibiting PRRSV replication in cell culture in a dose-dependant and sequence-specific manner. PPMO 5UP2 and 5HP are complementary to sequence in the 5′ end of the PRRSV genome, and 6P1 and 7P1 to sequence in the translation initiation regions of ORF6 and ORF7, respectively. Treatment of cells with 5UP2 or 5HP caused a 4.5log10 reduction in PRRSV yield, compared to a control PPMO. Combination of 6P1 and 7P1 led to higher level reduction than 6P1 or 7P1 alone. 5UP2, 5HP, and a combination of 6P1 and 7P1 inhibited PRRSV replication in porcine alveolar macrophages and protected the cells from PRRSV-induced cytopathic effect. Northern blot and real-time RT-PCR results demonstrated that the effective PPMO led to a reduction of PRRSV RNA level. 5UP2 and 5HP inhibited virus replication of 10 other strains of PRRSV. Results from this study suggest potential applications of PPMO for PRRS control. [Copyright &y& Elsevier]

Abstract: Human astroviruses (HAstVs) cause gastroenteritis. Real-time, reverse-transcription-polymerase chain reaction (RT2-PCR) was developed to quantitate HAstV RNA. An 88bp amplicon from the conserved 3′ genomic region was detected by binding of SYBR Green. RT2-PCR was reproducible, with a correlation coefficient of 0.998–1.00 and PCR efficiency of 94.4–100% (mean 97%). The coefficient of variation was 0.6–2.5%, dynamic range with RNA standard up to 5×108 RNA copies (RNACN) and sensitivity 5 RNACN. Of 54 blinded, archived stool samples from children hospitalized because of gastroenteritis tested by RT-PCR, 49 (91%) agreed by RT2-PCR for HAstV-positivity (Cohen κ =0.81, 95%CI 0.66–0.97). HAstV RNACN in stools ranged from 7.6×101 to 3.6×1014 copies/0.1g. Children coinfected with rotavirus had lower RNACN (mean log 4.22/standard deviation=2.26) than those without coinfection (7.57/3.06; p =.019). Children taking infant formula also had lower RNACN (5.96/2.98) than breast-fed or weaned children (8.73/2.92; p =.027). Higher RNACN tended to occur with longer duration of diarrhea for the episode (r =0.49, p =.064), but was not associated with change in age, gender, illness day, severity or breast-feeding. RT2-PCR quantitated HAstV RNA and RNACN in stool correlates with features of clinical illness. [Copyright &y& Elsevier]

Hepatitis E virus (HEV) causes predominantly acute and self-limiting hepatitis. However, in HEV-infected pregnant women, the case fatality rate because of fulminant hepatitis can be up to 30%. HEV infection is zoonotic for some genotypes. The HEV genome contains three open reading frames: ORF1 encodes the non-structural polyprotein involved in viral RNA replication; ORF2 encodes the capsid protein; ORF3 encodes a small multifunctional protein. Interferons (IFNs) play a significant role in the early stage of the host antiviral response. In this study, we discovered that the capsid protein antagonizes IFN induction. Mechanistically, the capsid protein blocked the phosphorylation of IFN regulatory factor 3 (IRF3) via interaction with the multiprotein complex consisting of mitochondrial antiviral-signaling protein (MAVS), TANK-binding kinase 1 (TBK1), and IRF3. The N-terminal domain of the capsid protein was found to be responsible for the inhibition of IRF3 activation. Further study showed that the arginine-rich-motif in the N-terminal domain is indispensable for the inhibition as mutations of any of the arginine residues abolished the blockage of IRF3 phosphorylation. These results provide further insight into HEV interference with the host innate immunity. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome virus (PRRSV) strain A2MC2 induces type I interferons in cultured cells. The objective of this study was to attenuate this strain by serial passaging in MARC-145 cells and assess its virulence and immunogenicity in pigs. The A2MC2 serially passaged 90 times (A2MC2-P90) retains the feature of interferon induction. The A2MC2-P90 replicates faster with a higher virus yield than wild type A2MC2 virus. Infection of primary pulmonary alveolar macrophages (PAMs) also induces interferons. Sequence analysis showed that the A2MC2-P90 has genomic nucleic acid identity of 99.8% to the wild type but has a deletion of 543 nucleotides in nsp2. The deletion occurred in passage 60. The A2MC2-P90 genome has a total of 35 nucleotide variations from the wild type, leading to 26 amino acid differences. Inoculation of three-week-old piglets showed that A2MC2-P90 is avirulent and elicits immune response. Compared with Ingelvac PRRS® MLV strain, A2MC2-P90 elicits higher virus neutralizing antibodies. The attenuated IFN-inducing A2MC2-P90 should be useful for development of an improved PRRSV vaccine. [ABSTRACT FROM AUTHOR]

The article presents a study on the function of viral FLICE inhibitory protein (vFLIP) encoded by Rhesus monkey rhadinovirus (RRV). The study showed that RRV vFLIP inhibits apoptosis induced by tumor necrosis factor-a (TNF-a) and cycloheximide. The vFLIP protects cells against apoptosis by enhancing autophagosome formation to extend cell survival.