2‐Pyridinyl‐4(3H)‐Quinazolinone: A Scaffold for Anti‐influenza A Virus Compounds

A series of 2‐pyridinyl‐3‐substituted‐4(3H)‐quinazolinones were synthesized, and their anti‐influenza A virus activities were determined using the cytopathic effect inhibition assay. Most of the compounds were potent with IC₅₀ values ranging from 51.6 to 93.0 μm , which are better than that of the currently marketed drug ribavirin. The molecular mechanisms of the new compounds were investigated using neuraminidase inhibition assay, cellular NF‐κB signaling pathway inhibition assay, and computational docking. Compound 4e , which is a N3 imidazol‐1‐ylpropyl‐substituted derivative of 2‐pyridinyl‐4(3H)‐quinazolinone, had the most potent anti‐influenza A virus activity in vitro, and inhibited both virus neuraminidase and cellular NF‐κB signaling pathway. In conclusion, 2‐pyridinyl‐4(3H)‐quinazolinone is a new scaffold for the design of potent anti‐influenza A virus compounds, offering an alternative approach to tackle influenza drug resistance.     

Factors associated with clinical and virological response in patients treated with oseltamivir or zanamivir for influenza A during the 2008–2009 winter

Oseltamivir or zanamivir are effective in outpatients with seasonal influenza; however, factors associated with response have been incompletely described. During the 2008/2009 epidemic, in a randomized trial for influenza A-infected outpatients, clinical (time to alleviation of flu-related symptoms) and virological (rate of patients with day 2 nasal viral load <200 cgeq/µL) responses to oseltamivir or zanamivir were assessed and associated factors were determined using multivariate analysis. For oseltamivir (141 patients) and zanamivir (149 patients) median times to alleviation of symptoms were 3 and 4 days, respectively; 59% and 34% had virological response. For oseltamivir, a lower clinical response was associated with female gender (HR, 0.53; 95% CI, 0.36–0.79), baseline symptoms score >14 (HR, 0.47; 0.32–0.70), viral load ≥5 log cgeq/µL (HR, 0.63; 0.43–0.93), and initiation of antibiotics (HR, 0.30; 0.12–0.76); a lower virological response was associated with female gender (OR, 0.45; 0.21–0.96), baseline viral load ≥5 log cgeq/µL (OR, 0.40; 0.20–0.84) and days 0–2 incomplete compliance (OR, 0.31; 0.10–0.98). For zanamivir, virological response was associated with age ≥50 years (OR, 0.29; 0.10–0.85) and initiation of antibiotics at baseline (OR, 4.24; 1.07–17.50). Factors associated with lower response to neuraminidase inhibitors in outpatients appeared to be easily identifiable during routine clinical examination and, when appropriate, by nasal sampling at baseline. The unknown association between gender and response to oseltamivir was not explained by compliance.     

2009H1N1流感病毒神经氨酸酶基因克隆与表达

目的制备2009H1N1流感病毒神经氨酸酶(NA)重组蛋白,为建立H1N1快速检测方法和神经氨酸酶抑制剂筛选模型奠定基础。方法采用MDCK细胞方法分离2009H1N1流感病毒,提取病毒RNA,RT-PCR生成NA基因,构建原核表达载体PET-102/D-TOPO-NA,IPTG诱导表达重组蛋白,SDS-PAGE凝胶电泳、WersternBlotting鉴定重组蛋白。结果成功分离2009H1N1流感病毒,NA蛋白119、152、275、292位氨基酸分别为Glu、Arg、His和Cys。SDS-PAGE凝胶电泳蛋白分子相对分子质量约为64000,与预期一致。WesternBlotting证实该蛋白具有神经氨酸酶抗原活性。结论 IPTG诱导原核表达神经氨酸蛋白的最适浓度为0.1mmol/L。实验得到的蛋白尚需进一步纯化。     

新型神经氨酸酶抑制剂的设计合成和药理活性测试

目的 为防控流感,设计合成新型神经氨酸酶抑制剂,并进行药理活性测试。方法 基于苯甲酸类神经氨酸酶抑制剂的结构,拼合具有抗病毒活性的酰基硫脲片段,利用前药原理设计并合成了I和Ⅱ系列共28个新型神经氨酸酶抑制剂并进行药理活性筛选。药理活性测试选用流感病毒菌株A/FM/1/47（H1N1）,分别进行神经氨酸酶单一浓度（10μmol·L^-1）抑制率和病毒抑制活性测试。结果 药理结果显示化合物I-2,I-5,I-11和I-12具有较好的病毒抑制活性,其中I-11的活性最佳,病毒抑制率达到70.50%,优于oseltamivir。结论 通过对28个化合物进行初步构效关系研究,为后续此类新型神经氨酸酶抑制剂的研究提供基础。     

Five years of monitoring for the emergence of oseltamivir resistance in patients with influenza A infections in the Influenza Resistance Information Study

Background and objectives

The Influenza Resistance Information Study (IRIS) was initiated in 2008 to study the emergence of neuraminidase inhibitor (NAI) resistance and the clinical course of influenza in immunocompetent treated and untreated patients.

Methods

Patients had throat/nose swabs collected on days 1, 3, 6 and 10 for analyses of influenza type, subtype and virus susceptibility to NAIs. RT‐PCR‐positive samples were cultured and tested for NAI resistance by specific RT‐PCR and phenotypic testing. Scores for influenza symptoms were recorded on diary cards (Days 1‐10). This study focuses on influenza A‐infected cases only.

Results

Among 3230 RT‐PCR‐positive patients, 2316 had influenza A of whom 1216 received oseltamivir monotherapy within 2 days of symptom onset (9 seasonal H1N1; 662 H3N2; 545 H1N1pdm2009). Except for 9 patients with naturally resistant seasonal H1N1 (2008/9), no resistance was detected in Day 1 samples. Emergence of resistance (post‐Day 1) was detected in 43/1207 (3.56%) oseltamivir‐treated influenza A‐infected patients, with a higher frequency in 1‐ to 5‐year‐olds (11.8%) vs >5‐year‐olds (1.4%). All N1‐ and N2‐resistant viruses had H275Y (n = 27) or R292K (n = 16) substitutions, respectively. For 43 patients, virus clearance was significantly delayed vs treated patients with susceptible viruses (8.1 vs 10.9 days; P < .0001), and 11 (23.2%) remained RT‐PCR positive for influenza at Day 10. However, their symptoms resolved by Day 6 or earlier.

Conclusions

Oseltamivir resistance was only detected during antiviral treatment, with the highest incidence occurring among 1‐ to 5‐year‐olds. Resistance delayed viral clearance, but had no impact on symptom resolution.     

禽流感病毒H5N2亚型A/Chicken/Gansu/2003株HA+NA基因重组腺病毒的构建

目的基于腺病毒可感染禽类呼吸道和肠道上皮黏膜的特性,本文构建了包含有禽流感病毒H5N2亚型HA和NA基因的重组腺病毒,为进一步研制口服禽流感活载体疫苗奠定基础。方法通过RT-PCR方法分别扩增出AIV的HA和NA全基因片段,利用拼接接头将HA和NA定向串联并插入到腺病毒穿梭载体pAdTrack-CMV之中,然后在大肠杆菌中实现腺病毒骨架载体pAdEasy-1和重组腺病毒穿梭载体的同源重组,获得插有外源基因的重组腺病毒质粒,进而通过转染HEK293细胞,得到含有目的基因HA和NA的重组腺病毒。结果在pAdTrack-CMV载体中成功克隆了HA+NA双基因,并与腺病毒骨架载体在大肠杆菌中实现了同源重组;线性化后的重组腺病毒质粒转染HEK293细胞后可观察到典型的细胞病变和绿色荧光蛋白的表达。结论成功获得了含有HA+NA双基因重的组腺病毒,为口服活载体疫苗的研制提供了依据。     

Neuraminidase delivered as an APC-targeted DNA vaccine induces protective antibodies against influenza

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Development of in ovo-compatible NS1-truncated live attenuated influenza vaccines by modulation of hemagglutinin cleavage and polymerase acidic X frameshifting sites

Emerging avian influenza viruses pose a high risk to poultry production, necessitating the need for more broadly protective vaccines. Live attenuated influenza vaccines offer excellent protective efficacies but their use in poultry farms is discouraged due to safety concerns related to emergence of reassortant viruses. Vaccination of chicken embryos inside eggs (in ovo) induces early immunity in young chicks while reduces the safety concerns related to the use of live vaccines on farms. However, in ovo vaccination using influenza viruses severely affects the egg hatchability. We previously engineered a high interferon-inducing live attenuated influenza vaccine candidate with an enhanced protective efficacy in chickens. Here, we asked whether we could further modify this high interferon-inducing vaccine candidate to develop an in ovo-compatible live attenuated influenza vaccine. We first showed that the enhanced interferon responses induced by the vaccine is not enough to attenuate the virus in ovo. To reduce the pathogenicity of the virus for chicken embryos, we replaced the hemagglutinin cleavage site of the H7 vaccine virus (PENPKTR/GL) with that of the H6-subtype viruses (PQIETR/GL) and disrupted the ribosomal frameshifting site responsible for viral polymerase acidic X protein expression. In ovo vaccination of chickens with up to 10⁵ median egg infectious dose of the modified vaccine had minimal effects on hatchability while protecting the chickens against a heterologous challenge virus at two weeks of age. This study demonstrates that targeted genetic mutations can be applied to further attenuate and enhance the safety of live attenuated influenza vaccines to develop future in ovo vaccines for poultry.