Oral Administration of a Prodrug of the Influenza Virus Neuraminidase Inhibitor GS 4071 Protects Mice and Ferrets against Influenza Infection

We have recently described GS 4071, a carbocyclic transition-state analog inhibitor of the influenza virus neuraminidase, which has potent inhibitory activity comparable to that of 4-guanidino-Neu5Ac2en (GG167; zanamivir) when tested against influenza A virus replication and neuraminidase activity in vitro. We now report that GS 4071 is active against several strains of influenza A and B viruses in vitro and that oral GS 4104, an ethyl ester prodrug which is converted to GS 4071 in vivo, is active in the mouse and ferret models of influenza virus infection. Oral administration of 10 mg of GS 4104 per kg of body weight per day caused a 100-fold reduction in lung homogenate viral titers and enhanced survival in mice infected with influenza A or B viruses. In ferrets, a 25-mg/kg dose of GS 4104 given twice daily reduced peak viral titers in nasal washings and eliminated constitutional responses to influenza virus infection including fever, increased nasal signs (sneezing, nasal discharge, mouth breathing), and decreased activity. Consistent with our demonstration that the parent compound is highly specific for influenza virus neuraminidases, no significant drug-related toxicity was observed after the administration of oral dosages of GS 4104 of up to 800 mg/kg/day for 14 days in nonclinical toxicology studies with rats. These results indicate that GS 4104 is a novel, orally active antiviral agent with the potential to be used for the prophylaxis and treatment of influenza A and B virus infections.     

Coadministration of Seasonal Influenza Vaccine and MVA-NP+M1 Simultaneously Achieves Potent Humoral and Cell-Mediated Responses

Current seasonal influenza vaccines have reduced immunogenicity and are of suboptimal efficacy in older adults. We have previously shown that the novel candidate vaccine MVA-NP+M1 is able to boost memory T cell responses in adults aged 50–85 years. Preclinical studies have demonstrated that viral vectored vaccines can act as adjuvants when coadministered with protein-based vaccines. We have conducted a phase I clinical trial to compare the coadministration of seasonal influenza vaccine and MVA-NP+M1 with seasonal influenza vaccine alone in adults aged 50 years and above. This combination of vaccines was safe and well tolerated. T cell responses to internal influenza proteins were boosted to significantly higher levels in the group receiving MVA-NP+M1 compared with the group receiving seasonal influenza vaccine alone. Rates of seroprotection and seroconversion against the three vaccine strains were similar in both groups; however, there was a significant increase in the geometric mean titer ratio for the H3N2 component of seasonal influenza vaccine in the coadministration group. While some vaccine combinations result in immune interference, the coadministration of MVA-NP+M1 alongside seasonal influenza vaccine is shown here to increase some influenza strain-specific antibody responses and boost memory T cells capable of recognizing a range of influenza A subtypes.     

A Multi-Targeting,Nucleoside-Modified mRNA Influenza Virus Vaccine Provides Broad Protection in Mice

1. Download : Download high-res image (172KB)
2. Download : Download full-size image

     

Variable Virulence and Efficacy of BCG Vaccine Strains in Mice and Correlation With Genome Polymorphisms

Bacille Calmette–Guérin (BCG), an attenuated strain of Mycobacterium bovis, is the only vaccine available for tuberculosis (TB) control. However, BCG is not an ideal vaccine and has two major limitations: BCG exhibits highly variable effectiveness against the development of TB both in pediatric and adult populations and can cause disseminated BCG disease in immunocompromised individuals. BCG comprises a number of substrains that are genetically distinct. Whether and how these genetic differences affect BCG efficacy remains largely unknown. In this study, we performed comparative analyses of the virulence and efficacy of 13 BCG strains, representing different genetic lineages, in SCID and BALB/c mice. Our results show that BCG strains of the DU2 group IV (BCG-Phipps, BCG-Frappier, BCG-Pasteur, and BCG-Tice) exhibit the highest levels of virulence, and BCG strains of the DU2 group II (BCG-Sweden, BCG-Birkhaug) are among the least virulent group. These distinct levels of virulence may be explained by strain-specific duplications and deletions of genomic DNA. There appears to be a general trend that more virulent BCG strains are also more effective in protection against Mycobacterium tuberculosis challenge. Our findings have important implications for current BCG vaccine programs and for future TB vaccine development.     

A Universal Influenza A Vaccine Based on Adenovirus Expressing Matrix-2 Ectodomain and Nucleoprotein Protects Mice From Lethal Challenge

A universal influenza vaccine, designed to induce broadly cross-reactive immunity against current and future influenza A virus strains, is in critical demand to reduce the need for annual vaccinations with vaccines chosen upon predicting the predominant circulating viral strains, and to ameliorate the threat of cyclically occurring pandemics that have, in the past, killed tens of millions. Here, we describe a vaccine regimen based on sequential immunization with two serologically distinct chimpanzee-derived replication-defective adenovirus (Ad) vectors expressing the matrix-2 protein ectodomain (M2e) from three divergent strains of influenza A virus fused to the influenza virus nucleoprotein (NP) for induction of antibodies to M2e and virus-specific CD8⁺ T cells to NP. In preclinical mouse models, the Ad vaccines expressing M2e and NP elicit robust NP-specific CD8⁺ T-cell responses and moderate antibody responses to all three M2e sequences. Most importantly, vaccinated mice are protected against morbidity and mortality following challenge with high doses of different influenza virus strains. Protection requires both antibodies to M2e and cellular immune responses to NP.     

Nasal Delivery of an Adenovirus-Based Vaccine Bypasses Pre-Existing Immunity to the Vaccine Carrier and Improves the Immune Response in Mice

Pre-existing immunity to human adenovirus serotype 5 (Ad5) is common in the general population. Bypassing pre-existing immunity could maximize Ad5 vaccine efficacy. Vaccination by the intramuscular (I.M.), nasal (I.N.) or oral (P.O.) route with Ad5 expressing Ebola Zaire glycoprotein (Ad5-ZGP) fully protected naïve mice against lethal challenge with Ebola. In the presence of pre-existing immunity, only mice vaccinated I.N. survived. The frequency of IFN-γ+ CD8+ T cells was reduced by 80% and by 15% in animals vaccinated by the I.M. and P.O. routes respectively. Neutralizing antibodies could not be detected in serum from either treatment group. Pre-existing immunity did not compromise the frequency of IFN-γ+ CD8+ T cells (3.9±1% naïve vs. 3.6±1% pre-existing immunity, PEI) nor anti-Ebola neutralizing antibody (NAB, 40±10 reciprocal dilution, both groups). The number of INF-γ+ CD8+ cells detected in bronchioalveolar lavage fluid (BAL) after I.N. immunization was not compromised by pre-existing immunity to Ad5 (146±14, naïve vs. 120±16 SFC/million MNCs, PEI). However, pre-existing immunity reduced NAB levels in BAL by ~25% in this group. To improve the immune response after oral vaccination, the Ad5-based vaccine was PEGylated. Mice given the modified vaccine did not survive challenge and had reduced levels of IFN-γ+ CD8+ T cells 10 days after administration (0.3±0.3% PEG vs. 1.7±0.5% unmodified). PEGylation did increase NAB levels 2-fold. These results provide some insight about the degree of T and B cell mediated immunity necessary for protection against Ebola virus and suggest that modification of the virus capsid can influence the type of immune response elicited by an Ad5-based vaccine.     

Heterosubtypic Protection Conferred by the Human Monoclonal Antibody PN-SIA28 against Influenza A Virus Lethal Infections in Mice

PN-SIA28 is a human monoclonal antibody (Hu-MAb) targeting highly conserved epitopes within the stem portion of the influenza virus hemagglutinin (HA) (N. Clementi, et al, PLoS One 6:e28001, 2011, http://dx.doi.org/10.1371/journal.pone.0028001). Previous in vitro studies demonstrated PN-SIA28 neutralizing activities against phylogenetically divergent influenza A subtypes. In this study, the protective activity of PN-SIA28 was evaluated in mice inoculated with lethal influenza A/WSN/33 (H1N1), A/Quebec/144147/09 (H1N1)pdm09, and A/Victoria/3/75 (H3N2) viruses. At 24 h postinoculation (p.i.), animals received PN-SIA28 intraperitoneally (1 or 10 mg/kg of body weight) or 10 mg/kg of unrelated Hu-MAb (mock). Body weight loss and mortality rate (MR) were recorded for 14 days postinfection (p.i.). Lung viral titers (LVT) were determined at day 5 p.i. In A/WSN/33 (H1N1)-infected groups, all untreated and mock-receiving mice died, whereas MRs of 87.5% and 25% were observed in mice that received PN-SIA28 1 and 10 mg/kg, respectively. In influenza A(H1N1) pdm09-infected groups, an MR of 75% was recorded for untreated and mock-treated groups, whereas the PN-SIA28 1-mg/kg and 10-mg/kg groups had rates of 62.5% and 0%, respectively. In A/Victoria/3/75 (H3N2)-infected animals, untreated and mock-treated animals had MRs of 37.5% and 25%, respectively, and no mortalities were recorded after PN-SIA28 treatments. Accordingly, PN-SIA28 treatments significantly reduced weight losses and resulted in a ≥1-log reduction in LVT compared to the control in all infection groups. This study confirms that antibodies targeting highly conserved epitopes in the influenza HA stem region, like PN-SIA28, not only neutralize influenza A viruses of clinically relevant subtypes in vitro but also, more importantly, protect from a lethal influenza virus challenge in vivo.     

Immunization of Mice with Urease Vaccine Affords Protection against Helicobacter pylori Infection in the Absence of Antibodies and Is Mediated by MHC Class II–restricted Responses

We examined the roles of cell- and antibody-mediated immunity in urease vaccine–induced protection against Helicobacter pylori infection. Normal and knockout mice deficient in major histocompatibility complex (MHC) class I, MHC class II, or B cell responses were mucosally immunized with urease plus Escherichia coli heat-labile enterotoxin (LT), or parenterally immunized with urease plus aluminum hydroxide or a glycolipid adjuvant, challenged with H. pylori strain X47-2AL, and H. pylori organisms and leukocyte infiltration in the gastric mucosa quantified. In an adjuvant/route study in normal mice, there was a direct correlation between the level of protection and the density of T cells recruited to the gastric mucosa. In knockout studies, oral immunization with urease plus LT protected MHC class I knockout mice [β₂-microglobulin (−/−)] but not MHC class II knockout mice [I-A^b (−/−)]. In B cell knockout mice [μMT (−/−)], vaccine-induced protection was equivalent to that observed in immunized wild-type (+/+) mice; no IgA⁺ cells were detected in the stomach, but levels of CD4⁺ cells equivalent to those in the wild-type strain (+/+) were seen. These studies indicate that protection of mice against H. pylori infection by immunization with the urease antigen is dependent on MHC class II–restricted, cell-mediated mechanisms, and antibody responses to urease are not required for protection.     

乙肝核酸疫苗接种小鼠后特异性抗原表达及CTL应答的动态观察

目的:观察乙肝病毒(hepatitis B virus,HBV)核酸疫苗pCMV-S2S免疫小鼠后,接种局部HBV preS2S抗原的表达及特异性细胞毒性T淋巴细胞(CTL)应答的动态变化。方法:将pCMV-S2S接种到BALB/c小鼠胫前肌,分别以免疫组化法检测接种局部肌肉HBV preS2S抗原表达的动态变化,乳酸脱氢酶(LDH)释放法检测特异性CTL活性的动态变化。结果:小鼠接种pCMV-S2S后,局部肌肉细胞3d后已有少量目的抗原HBV preS2S蛋白表达,4周时表达最强,至6月时仍可检出有preS2S蛋白表达,但表达强度明显减弱。小鼠接种pCMV-S2S3天后,特异性CTL活性平均值最高为21·67%,12周时CTL活性平均值最高为35·14%,6月时仍可检出较弱的CTL活性。结论:HBV核酸疫苗pCMV-S2S能在小鼠体内持续表达特异性抗原及诱生特异性CTL应答。     

HSV-1 Amplicon Vectors Launch the Production of Heterologous Rotavirus-like Particles and Induce Rotavirus-specific Immune Responses in Mice

Virus-like particles (VLPs) are promising vaccine candidates because they represent viral antigens in the authentic conformation of the virion and are therefore readily recognized by the immune system. As VLPs do not contain genetic material they are safer than attenuated virus vaccines. In this study, herpes simplex virus type 1 (HSV-1) amplicon vectors were constructed to coexpress the rotavirus (RV) structural genes VP2, VP6, and VP7 and were used as platforms to launch the production of RV-like particles (RVLPs) in vector-infected mammalian cells. Despite the observed splicing of VP6 RNA, full-length VP6 protein and RVLPs were efficiently produced. Intramuscular injection of mice with the amplicon vectors as a two-dose regimen without adjuvants resulted in RV-specific humoral immune responses and, most importantly, immunized mice were partially protected at the mucosal level from challenge with live wild-type (wt) RV. This work provides proof of principle for the application of HSV-1 amplicon vectors that mediate the efficient production of heterologous VLPs as genetic vaccines.     

Cell Wall Changes in Amphotericin B-Resistant Strains from Candida tropicalis and Relationship with the Immune Responses Elicited by the Host

We have morphologically characterized Candida tropicalis isolates resistant to amphotericin B (AmB). These isolates present an enlarged cell wall compared to isolates of regular susceptibility. This correlated with higher levels of β-1,3-glucan in the cell wall but not with detectable changes in chitin content. In line with this, AmB-resistant strains showed reduced susceptibility to Congo red. Moreover, mitogen-activated protein kinases (MAPKs) involved in cell integrity were already activated during regular growth in these strains. Finally, we investigated the response elicited by human blood cells and found that AmB-resistant strains induced a stronger proinflammatory response than susceptible strains. In agreement, AmB-resistant strains also induced stronger melanization of Galleria mellonella larvae, indicating that the effect of alterations of the cell wall on the immune response is conserved in different types of hosts. Our results suggest that resistance to AmB is associated with pleiotropic mechanisms that might have important consequences, not only for the efficacy of the treatment but also for the immune response elicited by the host.     

A Validated Smartphone-based Electrocardiogram Reveals Severe Bradyarrhythmias during Immobilizing Restraint in Mice of Both Sexes and Four Strains

Mouse handling and restraint affect behavior, physiology, and animal welfare, yet little information is available on how various mouse restraint methods affect cardiovascular parameters. We validated the use of a smartphone-based ECG system in mice by performing simultaneous smartphone and telemetry ECG recordings in conscious, restrained mice and in anesthetized mice. We observed that mice held in standard immobilizing restraint (“scruffing”) experienced severe bradycardia. Mice of both sexes and 4 different strains (BALB/cJ, C57BL/6J, DBA/2J, and FVB/nJ) were restrained by 3 handlers using 3 different restraint methods: light restraint; 3-finger restraint, which creates a dorsal transverse fold of skin; and the standard immobilizing restraint, which creates a dorsal longitudinal fold of skin that results in a crease on the ventral neck. Regardless of the handler, immobilizing restraint, but not 3-finger restraint, produced severe bradycardia with irregular rhythm in all 4 strains and both sexes, with an average decrease in heart rate of 31%, or 211 bpm, and a maximal decrease of 79%, or 542 bpm. When evaluated using telemetry, immobilizing restraint produced severe arrhythmias such as junctional and ventricular escape rhythms, and second- and third-degree atrioventricular block. Sinus pauses were observed for an average of 4 min, but up to 6.8 min after release from immobilizing restraint. Atropine administration to C57BL/6J mice attenuated immobilizing restraint-induced bradycardia, supporting the hypothesis that pressure on cervical baroreceptors during stretching of the neck skin results in a vagally-mediated reflex bradycardia. Because of these profound cardiovascular effects, we recommend using the light or 3-finger restraint and avoiding or minimizing the use of immobilization restraint while handling mice.

Animals often must be handled and restrained to achieve research goals. Procedures requiring restraint have well documented effects on behavior and physiology, and thus may affect animal welfare. Many studies have now assessed how routine, seemingly innocuous procedures may affect research study results, and how subtle variations in handling and restraint can affect animal welfare and the reproducibility of experiments.Handling can have a profound impact on physiologic and behavioral parameters and may influence study outcomes. Handling has been associated with alterations in metabolism and the immune system in mice and rat pups.^1,25,35 C57BL/6 mice showed increases in heart rate (HR), systolic blood pressure, and core body temperature that persisted for a few hours after handling.⁵⁰ However, all methods of handling mice do not have equivalent effects on behavior and physiology. Using a tunnel for handling, as compared with grasping the mouse by the base of the tail, increased exploratory behaviors and reduced anxiety and depressive-associated behaviors.^6,11,17 In contrast, handling by the tail base was associated with relatively higher urination, defecation,¹⁷ blood glucose,¹¹ and tumor growth,¹ but did not change heart rate or central blood pressure.⁵⁰ The effects of tail handling, as compared with tunnel handling, are long lasting despite efforts at habituation.^13,50 Furthermore, when compared with handling by the tail, tunnel handling of ICR mice reduced the coefficient of variation in an elevated plus maze.³³ The response to handling varies by strain, sex, duration of handling and method of animal transfer, contributing to variation across studies.^1,17Many researchers must manually restrain animals for basic procedures. This is despite the results of a study suggesting that manual restraint is aversive to mice,¹⁷ and that tail handling followed by manual restraint and abdominal palpation results in an acute heart rate increase of approximately 100 beats per minute that persists over half an hour.³¹ In the United States, mice are commonly manually immobilized by “scruffing”, which produces a longitudinal fold of skin from the occiput extending caudally along the dorsum.⁴² Depending on the strength of the grip, this technique will cause a crease on the ventral neck and abducted immobilization of the forelimbs. Training courses instruct students to avoid putting too much pressure on the neck when using this method, and to constantly monitor the mouse for dyspnea and cyanosis, as novice handlers may inadvertently cause mice to acutely die due to obstruction of the airway.⁴²To reduce the need for scruffing, alternative mouse restraint methods have been developed. Norecopa, Norway''s 3R Center, has published a “three-finger” restraint method with instructional videos available online.³⁴ This method produces a transverse fold of skin on the dorsum, but no crease on the ventral neck. This method is posited to reduce stress to the mouse. Different handling methods are likely to have measurable differences in how they affect the murine stress response and physiology. However, to our knowledge, no studies to date have evaluated the effects of different manual restraint methods on cardiac physiology.Handling and restraint undoubtedly affect heart rate and central blood pressure, such that cardiac research emphasizes the use of unrestrained animals.^31,50 Electrocardiograms (ECGs) measure the electrical activity of the heart and are valuable in assessing cardiac physiology. The gold standard for ECGs in conscious mice is the use of either intraperitoneally or subcutaneously implanted radiotelemetry devices.^16,22 These devices transmit wirelessly to a receiver via radiofrequency waves and allow recording of high-quality, high resolution continuous waveforms in unrestrained mice for long periods of time.¹⁶ However, disadvantages are inherent in using radiotelemetry in mice. Implanting a large radiotelemetry device requires invasive surgery and a skilled surgeon, resulting in prolonged recovery time, single housing, and associated morbidity and mortality.¹⁶ In addition, radiotelemetry devices and associated equipment are not available at many institutions and may be prohibitively expensive. To address these disadvantages, several commercially available, noninvasive ECG options are marketed for use in conscious mice. These systems are expensive and produce short recordings (several seconds) that allow rapid screening of mice.¹⁶ Standard ECG equipment used for larger species is often unsuitable for small species, due to size limitations and the requirement of physical or chemical restraint, both of which may adversely affect physiologic parameters.¹⁶ Overall, ECG modalities requiring restraint can be useful if invasive modalities are not possible or necessary. Comparisons of these approaches can provide useful information on the effects of restraint and handling on cardiovascular parameters.In this study, we used a commercially available, noninvasive smartphone-based ECG device in conscious, restrained mice to measure the cardiovascular effects of 3 manual restraint methods. The smartphone ECG (SP-ECG) used is a single lead ECG device that performs real-time recording via ultrasonic audio and proprietary wireless communication to a smartphone application. The company markets similar validated FDA-cleared products to human patients for at-home use, specifically for detection of atrial fibrillation.¹⁵ Due to its small size, affordable cost, and ease of use, the veterinary community has also taken an interest in the SP-ECG, and it has been validated in dogs and cats,^23,46,48 horses,⁴⁷ dairy water buffalo calves,⁴³ and dairy cattle.²Here, we validate the use of the SP-ECG against telemetry for assessing HR and rhythm in conscious, restrained mice. We hypothesized that SP-ECG can be used for screening of HR abnormalities in mice. By using SP-ECG, we found that manual restraint of mice by immobilization (scruffing), as compared with the less restrictive “three-finger” restraint method, produces severe, vagally-mediated bradyarrhythmias. We therefore advocate minimal handling and suggest the use of the “three-finger” restraint method when possible for the routine handling of laboratory mice.     

Activity of the Oral Neuraminidase Inhibitor A-322278 against the Oseltamivir-Resistant H274Y (A/H1N1) Influenza Virus Mutant in Mice

The new oral neuraminidase (NA) inhibitor A-322278 was evaluated in mice infected with influenza A/H1N1 wild-type virus or the oseltamivir-resistant (H274Y mutant) virus. A-322278 decreased mortality rates and lung virus titers significantly more than oseltamivir in mice infected with the NA H274Y mutant when therapy was started 4 h before or even 48 h after infection.     

Effects of the Combination of Favipiravir (T-705) and Oseltamivir on Influenza A Virus Infections in Mice

Favipiravir (T-705 [6-fluoro-3-hydroxy-2-pyrazinecarboxamide]) and oseltamivir were combined to treat influenza virus A/NWS/33 (H1N1), A/Victoria/3/75 (H3N2), and A/Duck/MN/1525/81 (H5N1) infections. T-705 alone inhibited viruses in cell culture at 1.4 to 4.3 μM. Oseltamivir inhibited these three viruses in cells at 3.7, 0.02, and 0.16 μM and in neuraminidase assays at 0.94, 0.46, and 2.31 nM, respectively. Oral treatments were given twice daily to mice for 5 to 7 days starting, generally, 24 h after infection. Survival resulting from 5 days of oseltamivir treatment (0.1 and 0.3 mg/kg/day) was significantly better in combination with 20 mg/kg of body weight/day of T-705 against the H1N1 infection. Treatment of the H3N2 infection required 50 mg/kg/day of oseltamivir for 7 days to achieve 60% protection; 25 mg/kg/day was ineffective. T-705 was ≥70% protective at 50 to 100 mg/kg/day but inactive at 25 mg/kg/day. The combination of inhibitors (25 mg/kg/day each) increased survival to 90%. The H5N1 infection was not benefited by treatment with oseltamivir (≤100 mg/kg/day for 7 days). T-705 was 30 to 70% protective at 25 to 100 mg/kg/day. Survival improved slightly with combination treatments. Increased activity was seen against H5N1 infection by starting treatments 2 h before infection. Oseltamivir was ineffective at ≤40 mg/kg/day. T-705 was 100% protective at 40 and 80 mg/kg/day and inactive at 20 mg/kg/day. Combining ineffective doses (20 mg/kg/day of T-705 and 10 to 40 mg/kg/day of oseltamivir) afforded 60 to 80% protection and improved body weights during infection. Thus, synergistic responses were achieved with low doses of T-705 combined with oseltamivir. These compounds may be viable candidates for combination treatment of human influenza infections.The emergence of swine influenza H1N1 virus infections in 2009 (2) highlights the need for effective antiviral therapy in a largely immune-naïve population. Treatment options for influenza are becoming more limited because viruses, including the 2009 swine H1N1 virus, are resistant to the antiviral drugs amantadine and rimantadine (3, 4, 11, 13, 20). Oseltamivir-resistant viruses are also becoming more common in the environment, particularly within the last 2 years (1, 5, 19). Thus, more potent and effective treatments are needed to combat these growing threats.More potent antiviral therapy can be achieved by using drugs in combination, as demonstrated in mouse models (10, 14-17, 24, 26, 27). Such treatment can slow down the emergence of drug-resistant viruses (12). The reported animal studies have primarily focused on the known-active antiviral agents amantadine, rimantadine, oseltamivir, peramivir, zanamivir, and ribavirin. The kinds of studies that can be performed have been limited based upon the number of active antiviral compounds that are available.In 2002, Furuta et al. reported a novel pyrazine molecule, T-705 (6-fluoro-3-hydroxy-2-pyrazinecarboxamide, now named favipiravir), as an inhibitor of influenza virus infections in cell culture and in mice (8). T-705 inhibits both influenza A and B viruses (8, 23, 29). The compound converts to nucleoside mono- (T-705 RMP [ribosylated, monophosphorylated]), di-, and triphosphate (T-705 RTP [ribosylated, triphosphorylated]) forms in cells (9). The mode of action of T-705 RTP is similar to that of ribavirin triphosphate as an inhibitor of influenza virus RNA polymerase (6, 9). Unlike ribavirin monophosphate, T-705 RMP is only weakly inhibitory to cellular inosine monophosphate (IMP) dehydrogenase (9, 28), and thus, it is less cytotoxic. These properties make T-705 a viable candidate for the treatment of influenza virus infections in humans. The compound is currently undergoing phase II clinical trials.The use of T-705 in combination with other antiviral substances has not been reported. The purpose of the present work was to evaluate whether the combination of T-705 with the widely used antiviral drug oseltamivir is more beneficial than either substance used alone against influenza virus infections in mice. We chose three mouse-adapted influenza viruses for these comparisons, A/NWS/33 (H1N1), A/Victoria/3/75 (H3N2), and A/Duck/MN/1525/81 (H5N1). The A/NWS and A/Victoria viruses are of seasonal origin and are confined to the respiratory tract following infection. The A/Duck virus is a low-pathogenicity avian virus from the United States that also does not spread beyond the respiratory tract of mice. The experimental influenza A/Duck mouse infection does not fully reflect the type of pathogenesis of the highly pathogenic avian influenza H5N1 viruses from the Old World. This is because the A/Duck virus lacks the multibasic amino acid R-X-R/K-R motif in the hemagglutinin protein, whereas the highly pathogenic avian H5N1 viruses contain it (7). This motif allows for the highly pathogenic viruses to be proteolytically activated by ubiquitous subtilisin-like cellular proteases, allowing the virus to spread in vivo beyond the respiratory tract and to cause multiorgan failure. Nevertheless, the A/Duck virus induces rapid, severe lung infections that are difficult to treat with conventional antiviral therapy. Using these three models, H1N1, H3N2, and H5N1, in mice, we were able to demonstrate the benefits of using oseltamivir and T-705 in combination to treat influenza virus infections.     

In Vivo Expansion of Regulatory T cells With IL-2/IL-2 mAb Complexes Prevents Anti-factor VIII Immune Responses in Hemophilia A Mice Treated With Factor VIII Plasmid-mediated Gene Therapy

Generation of transgene-specific immune responses can constitute a major complication following gene therapy treatment. An in vivo approach to inducing selective expansion of Regulatory T (Treg) cells by injecting interleukin-2 (IL-2) mixed with a specific IL-2 monoclonal antibody (JES6-1) was adopted to modulate anti-factor VIII (anti-FVIII) immune responses. Three consecutive IL-2 complexes treatments combined with FVIII plasmid injection prevented anti-FVIII formation and achieved persistent, therapeutic-level of FVIII expression in hemophilia A (HemA) mice. The IL-2 complexes treatment expanded CD4⁺CD25⁺Foxp3⁺ Treg cells five- to sevenfold on peak day, and they gradually returned to normal levels within 7–14 days without changing other lymphocyte populations. The transiently expanded Treg cells are highly activated and display suppressive function in vitro. Adoptive transfer of the expanded Treg cells protected recipient mice from generation of high-titer antibodies following FVIII plasmid challenge. Repeated plasmid transfer is applicable in tolerized mice without eliciting immune responses. Mice treated with IL-2 complexes mounted immune responses against both T-dependent and T-independent neoantigens, indicating that IL-2 complexes did not hamper the immune system for long. These results demonstrate the important role of Treg cells in suppressing anti-FVIII immune responses and the potential of developing Treg cell expansion therapies that induce long-term tolerance to FVIII.     

被动物Ⅲ度咬伤者联合使用狂犬病疫苗和免疫球蛋白免疫实验研究

按ＷＨＯ标准选择１７１例被动物Ⅲ度咬伤者联合使用法国产ＰＶＲＶ和ＥＲＩＧ进行免疫，观察其免疫效果、全身及局部反应，评价其有效性和安全性。结果表明，全身反应发生率为７．６０％，ＰＶＲＶ和ＥＲＩＧ局部反应发生率分别为１．３０％和１０．５３％。应用ＲＦＦＩＴ动态检测５１例患者，第０、７、１４和２８天的阳性率分别为０％、４１．１８％、１００％和１００％，ＧＭＴ分别为０．０３、０．３８、１１８．８３和９６．２９ＩＵ。联合使用ＰＶＲＶ和ＥＲＩＧ进行免疫，异常反应少而轻，安全性好；中和抗体免后第１４天即达到高峰