Bioinformatic Analysis of Non-VP1 Capsid Protein of Coxsackievirus A6

This study bioinformatically analyzed the non-VP1 capsid proteins（VP2-VP4） of Coxasckievirus A6（CVA6）, with an attempt to predict their basic physicochemical properties, structural/functional features and linear B cell eiptopes. The online tools Sub Loc, Target P and the others from Ex PASy Bioinformatics Resource Portal, and SWISS-MODEL（an online protein structure modeling server）, were utilized to analyze the amino acid（AA） sequences of VP2-VP4 proteins of CVA6. Our results showed that the VP proteins of CVA6 were all of hydrophilic nature, contained phosphorylation and glycosylation sites and harbored no signal peptide sequences and acetylation sites. Except VP3, the other proteins did not have transmembrane helix structure and nuclear localization signal sequences. Random coils were the major conformation of the secondary structure of the capsid proteins. Analysis of the linear B cell epitopes by employing Bepipred showed that the average antigenic indices（AI） of individual VP proteins were all greater than 0 and the average AI of VP4 was substantially higher than that of VP2 and VP3. The VP proteins all contained a number of potential B cell epitopes and some eiptopes were located at the internal side of the viral capsid or were buried. We successfully predicted the fundamental physicochemical properties, structural/functional features and the linear B cell eiptopes and found that different VP proteins share some common features and each has its unique attributes. These findings will help us understand the pathogenicity of CVA6 and develop related vaccines and immunodiagnostic reagents.

Preparation and immunoprotective effects of a virus-like particle candidate vaccine of the dominant epidemic D3 genotype coxsackievirus A6 in China

Coxsackievirus A6 of the D3a genotype(CVA6 D3a)is a primary pathogen causingmainland of China's hand,foot,and mouth disease(HFMD).Viral‐like particle(VLP)vaccines represent a potential candidate vaccine to prevent HFMD.This study collected Anti‐CVA6 D3a VLPs serum from BALB/c female mice immunized using CVA6 D3a VLPs.The neutralizing antibody levels were compared against the representative 14‐JX2018(D3a)and N4‐YN2015(D3b)strains between the antisera of different immune pathways.The immunoprotective effect of anti‐CVA6 D3a VLPs against these strains was monitored using pathological sections and immuno-histochemical results of lung and skeletal muscle tissues in seven‐day‐old Institute of Cancer Research(ICR)mice.Immunological protection against different branches of viruses was evaluated in 7‐day‐old(serum passive immune protection)and 14‐day‐old(VLPs active immune protection)neonatal ICR mice models.Serum‐neutralizing antibody levels were positively correlated with the number of immunizations and higher against 14‐JX2018 than against N4‐YN2015.Furthermore,these levels were significantly higher with abdominal injection than intramuscular injection.The immunized serum of 7‐day‐old ICR mice inoculated three times was 100%protected against CVA6 D3a 14‐JX2018(lethal titer:106.25 TCID 50)and CVA6 D3b N4‐YN2015(lethal titer:105.25TCID 50)fatal attacks,respectively.For ICR mice that have completed two active immunizations for 14 days,both CVA6 D3a 14‐JX2015(challenge titer:108.25 TCID 50)and CVA6 D3b N4‐YN2015(challenge titer:107.25 TCID 50)were used for the challenge,and the mice were able to survive.Overall,the CVA6 D3a VLPs prepared in this study are a potential vaccine candidate for CVA6,as it has the optimal protective effect against both CVA6 D3a and D3b evolutionary branches viruses.

Genetic Variation of Multiple Serotypes of Enteroviruses Associated with Hand, Foot and Mouth Disease in Southern China

Enteroviruses(EVs)species A are a major public health issue in the Asia–Pacific region and cause frequent epidemics of hand,foot and mouth disease(HFMD)in China.Mild infections are common in children;however,HFMD can also cause severe illness that affects the central nervous system.To molecularly characterize EVs,a prospective HFMD virological surveillance program was performed in China between 2013 and 2016.Throat swabs,rectal swabs and stool samples were collected from suspected HFMD patients at participating hospitals.EVs were detected using generic real-time and nested reverse transcription-polymerase chain reactions(RT-PCRs).Then,the complete VP1 regions of enterovirus A71(EV-A71),coxsackievirus A16(CVA16)and CVA6 were sequenced to analyze amino acid changes and construct a viral molecular phylogeny.Of the 2836 enrolled HFMD patients,2,517(89%)were EV positive.The most frequently detected EVs were CVA16(32.5%,819),CVA6(31.2%,785),and EV-A71(20.4%,514).The subgenogroups CVA16B1 b,CVA6D3 a and EV-A71C4 a were predominant in China and recombination was not observed in the VP1 region.Sequence analysis revealed amino acid variations at the 30,29 and 44 positions in the VP1 region of EV-A71,CVA16 and CVA6(compared to the respective prototype strains Br Cr,G10 and Gdula),respectively.Furthermore,in 21 of 24(87.5%)identified EV-A71 samples,a known amino acid substitution(D31 N)that may enhance neurovirulence was detected.Our study provides insights about the genetic characteristics of common HFMD-associated EVs.However,the emergence and virulence of the described mutations require further investigation.

心安颗粒对病毒性心肌炎小鼠IL-6,TNF-α及病毒复制的影响

目的:研究心安颗粒对病毒性心肌炎(viral myocarditis,VMC)小鼠的柯萨奇B3病毒(CVB3)mRNA,白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)水平的影响。方法:将60只健康雄性BALB/c小鼠随机分为6组,空白组、模型组、利巴韦林组(阳性药物,0.02 g·kg-1·d-1)和心安颗粒高、中、低剂量组(12,6,3 g·kg-1·d-1),其中空白组腹腔接种0.15 m L生理盐水,其余5组均腹腔接种1×10-8TCID50·m L-1CVB3 Nancy标准病毒液0.15 m L,进行模型制备。造模2 h后对各给药组小鼠灌胃(ig)相应药物,空白组和模型组小鼠ig生理盐水,连续7 d。7 d后小鼠进行实验,观察小鼠心肌组织病理变化,并进行评分;实时荧光定量聚合酶链式反应(Real-time PCR)检测心肌组织中CVB3 mRNA水平和蛋白质免疫印迹法(Western blot)检测TNF-α,IL-6蛋白表达。结果:给药7 d后,与空白组比较,模型组心肌细胞排列紊乱,出现间质水肿,可见大量炎症细胞浸润,发生明显病变,心肌病变评分和心肌组织中CVB3 mRNA表达水平和IL-6,TNF-α蛋白水平明显升高(P<0.05);与模型组比较,各给药组小鼠心肌组织病变得到改善,病理评分和心肌组织中CVB3 mRNA和TNF-α,IL-6蛋白水平明显降低(P<0.05)。结论:心安颗粒可明显下调病毒性心肌炎模型小鼠心肌组织中CVB3 mRNA和TNF-α,IL-6蛋白水平的表达,推测是其防治病毒性心肌炎的作用机制之一。