Bioinformatics analysis of VP1 of Coxsackievirus A10 / 公共卫生与预防医学

Objective To predict and analyze the physicochemical properties, structural characteristics, and antigenic epitopes of viral protein (VP) VP1 of Coxsackievirus A10 (CV-A10) by bioinformatics methods. Methods The physicochemical properties and structural characteristics of CV-A10 VP1 were predicted by ProtParam, SOPMA, SWISS-MODEL, PDBsum, and ProSA-web. The antigenic epitopes of CV-A10 VP1 were predicted and analyzed by DNAstar, ABCpred, Bepipred 2.0, ElliPro, DiscoTope-2.0, NetMHCpan-4.1, NetMHCIIpan-4.0, Consurf, VaxiJen v.2.0, AllerTOP v.2.0, ToxinPred2, and IEDB immunogenicity. Results Bioinformatics analysis showed that CV-A10 VP1 was a basic, unstable, and hydrophilic protein, of which the secondary structure mainly consisted of random coil. The analysis revealed that CV-A10 VP1 had multiple potential B and T cell antigenic epitopes as well as a dominant antigenic epitope based on the potential epitope. Conclusion CV-A10 VP1 has multiple potential sites that induce specific humoral and cellular immunity, providing important support for its experimental identification, molecular epidemiological studies, and vaccine development.

Phylogenetic and antigenic analysis of HA gene of influenza virus B (Victoria) in Beijing during 2021-2022 surveillance season / 中华微生物学和免疫学杂志

Objective:To investigate the phylogenetic and antigenic characteristics of hemagglutinin (HA) gene of influenza B/Victoria lineage (BV) viruses in Beijing during the 2021-2022 influenza surveillance season, and to analyze whether the circulating BV viruses match the vaccine strain.Methods:Pharyngeal swab specimens from influenza like-illness (ILI) cases in the 2021-2022 influenza surveillance season were collected from surveillance network labs in Beijing and cultured in MDCK cells and chicken embryo to isolate BV viruses. Nucleic acids of the viruses were extracted, and the HA gene was amplified and sequenced. The nucleotide and amino acid sequence identity of the HA gene was analyzed using MEGA5.0 software. A phylogenetic tree of HA gene was constructed using the maximum likelihood method. The N-glycosylation sites in HA were predicted online. Three-dimensional structure of HA was constructed using SWISS-MODEL homologous modeling. Hemagglutination inhibition (HI) test was performed to analyze the antigenicity of BV viruses.Results:A total of 402 BV viruses were collected and 58 strains with full-length HA gene sequences were chosen for further analysis. Compared with the HA gene of this year′s vaccine strain (B/Washington/02/2019), there were 27 amino acid mutations, 11 of which were located in four different antigenic determinants. The phylogenetic analysis revealed that three subgroups of 1A.3, 1A.3a1, and 1A.3a2 co-circulated in Beijing with 54 strains (54/58, 93.10%) clustered to the Clade 1A.3a2, two strains (2/58, 3.45%) clustered to the Clade 1A.3a1, and two strains (2/58, 3.45%) in the same subgroup (Clade 1A.3) as the vaccine component BV strain in 2021-2022. Compared with the vaccine strain (B/Washington/02/2019), two BV strains had an additional N-glycosylation site at residue 197, while the other 56 strains showed no change in N-glycosylation sites. Antigenic analysis showed that 35 BV strains (35/58, 60.34%) were antigenically similar to the vaccine strain and 23 strains (23/58, 39.66%) were low-response strains.Conclusions:Three subgroups of BV viruses co-circulated in Beijing during the 2021-2022 influenza surveillance season. The predominant subgroup was Clade 1A.3a2 (93.10%), showing a certain genetic distance with the vaccine strain (B/Washington/02/2019). Nearly 40% (39.66%) of the viruses were low-response strains. This study indicated that continuous monitoring of the variations of influenza epidemic strains and timely providing laboratory basis for screening vaccine component strains were the basic technical guarantee for coping with influenza pandemic.

Sequence characteristics of Rhipicephalus microplus Enolase gene and prediction of structure and antigenic epitopes of its encoding protein / 中国血吸虫病防治杂志

Objective To analyze the sequence characteristics of Rhipicephalus microplus Enolase gene, and to predict the secondary and tertiary structure and antigenic epitopes of the Enolase protein. Methods Sixty-two engorged female R. microplus were sampled from a yellow cattle breeding farm in Zhijiang County, Huaihua City, Hunan Province in June 25, 2022. Genomic DNA was isolated from R. microplus, and the Enolase gene was amplified using PCR assay, followed by cloning, sequencing and expression of the amplification product. The sequence characteristics of the Enolase gene were analyzed using the software Clustal X, and the gene sequence was translated into amino acid sequences. The secondary and tertiary structures of the Enolase protein were deduced using the software PRABI, and the physicochemical properties of the Enolase protein were analyzed using the software PRABI. In addition, the B- and T-cell epitopes of the Enolase protein were predicted using the software ABCpred Prediction, Scratch, IEDB and NetCTL. Results The R. microplus Enolase gene sequence was 1 323 bp in size, and the contents of A, T, G and C bases were 24.5%, 22.5%, 27.0% and 26.0%,with 47.0% of A + T content and 53.0% of G + C content. The R. microplus Enolase gene encoded 434 amino acids, and the Enolase protein had a molecular weight of 47.12 kDa. The secondary structure of the Enolase protein contained 186 α-helixes (42.86%), 32 β-turns (7.37%), 144 random coils (33.18%) and 72 extended strands (16.59%). The Enolase protein was most probably present in cytoplasm (76.7%), followed by in mitochondrion (39.1%) and nucleus (21.7%), and the Enolase protein had no signal peptide or transmembrane domain. In addition, the Enolase protein had 14 B-cell dominant epitopes and 8 T-cell dominant epitopes. Conclusions The R. microplus Enolase gene sequence exhibits a GC preference, and its encoding Enolase protein is an acidic and hydrophilic protein, with α-helixes and random coils as its primary structure, and presenting B- and T-cell dominant epitopes, which is a potential target for development of vaccines against R. microplus.

The dichotomous role of immunoproteasome in cancer: Friend or foe?

Immunoproteasome is a variant of proteasome with structural differences in 20S subunits optimizing them for the production of antigenic peptides with higher binding affinity to major histocompatibility complex (MHC)-I molecules. Apart from this primary function in antigen presentation, immunoproteasome is also responsible for the degradation of proteins, both unfolded proteins for the maintenance of protein homeostasis and tumor suppressor proteins contributing to tumor progression. The altered expression of immunoproteasome is frequently observed in cancers; however, its expression levels and effects vary among different cancer types exhibiting antagonistic roles in tumor development. This review focuses on the dichotomous role of immunoproteasome in different cancer types, as well as summarizes the current progression in immunoproteasome activators and inhibitors. Specifically targeting immunoproteasome may be a beneficial therapeutic intervention in cancer treatment and understanding the role of immunoproteasome in cancers will provide a significant therapeutic insight for the prevention and treatment of cancers.

Toxocara canis 30-35 kDa excretory-secretory antigen is an important marker in mice challenged by inocula containing different parasite load levels

ABSTRACT The Western-blotting technique was applied to identify antigenic fractions of excretory-secretory Toxocara canis antigen recognized by IgG antibodies throughout an experimental infection in mice challenged by different inocula. Mice were inoculated with 5, 50 and 500 embryonated eggs and serum samples were collected 15, 30, 60, 90 and 120 days post-infection. Serum samples were analyzed using an excretory-secretory Toxocara antigen. Antibodies recognized antigenic fractions from 30 to 90 kDa. The protein fraction of 30-35 kDa was the most frequently recognized regardless of the size of inoculum and the stage of infection represented by the different collection times, but the antigenic recognition was more evident in groups infected with 50 and 500 eggs. This study presents an antigenic panel of the excretory-secretory antigen of T. canis and suggests that the 30-35 kDa antigenic fraction is a promising marker of the infection and should be further explored in future studies on experimental toxocariasis.

Characterization of a monoclonal antibody against the hemagglutinin stem of H7N9 subtype avian influenza virus / 生物工程学报

The conserved hemagglutinin (HA) stem region of avian influenza virus (AIV) is an important target for designing broad-spectrum vaccines, therapeutic antibodies and diagnostic reagents. Previously, we obtained a monoclonal antibody (mAb) (5D3-1B5) which was reactive with the HA stem epitope (aa 428-452) of H7N9 subtype AIV. To systematically characterize the mAb, we determined the antibody titers, including the HA-binding IgG, hemagglutination-inhibition (HI) and virus neutralizing (VN) titers. In addition, the antigenic epitope recognized by the antibody as well as the sequence and structure of the antibody variable region (VR) were also determined. Moreover, we evaluated the cross-reactivity of the antibody with influenza virus strains of different subtypes. The results showed that the 5D3-1B5 antibody had undetectable HI and VN activities against H7N9 virus, whereas it exhibited strong reactivity with the HA protein. Using the peptide-based enzyme-linked immunosorbent assay and biopanning with a phage-displayed random peptide library, a motif with the core sequence (431W-433Y-437L) in the C-helix domain in the HA stem was identified as the epitope recognized by 5D3-1B5. Moreover, the mAb failed to react with the mutant H7N9 virus which contains mutations in the epitope. The VR of the antibody was sequenced and the complementarity determining regions in the VR of the light and heavy chains were determined. Structural modeling and molecular docking analysis of the VR verified specific binding between the antibody and the C-helix domain of the HA stem. Notably, 5D3-1B5 showed a broad cross-reactivity with influenza virus strains of different subtypes belonging to groups 1 and 2. In conclusion, 5D3-1B5 antibody is a promising candidate in terms of the development of broad-spectrum virus diagnostic reagents and therapeutic antibodies. Our findings also provided new information for understanding the epitope characteristics of the HA protein of H7N9 subtype AIV.

Prokaryotic expression of a recombinant protein of adeno-associated virus capsid conserved regions and preparation of its polyclonal antibody / 南方医科大学学报

OBJECTIVE@#To express and purify the antigenic peptide of adeno-associated virus (AAV) capsid conserved regions in prokaryotic cells and prepare its rabbit polyclonal antibody.@*METHODS@#The DNA sequence encoding the conserved regions of AAV capsid protein was synthesized and cloned into the vector pET30a to obtain the plasmid pET30a-AAV-CR for prokaryotic expression and purification of the conserved peptides. Coomassie blue staining and Western blotting were used to identify the AAV conserved peptides. Japanese big ear white rabbits were immunized with AAV conserved region protein to prepare polyclonal antibody, with the rabbits injected with PBS as the control group. The antibody titer was determined with ELISA, and the performance of the antibody for recognizing capsid protein sequences of AAV1-AAV10 was assessed with Western blotting and immunofluorescence assay.@*RESULTS@#The plasmid pET30a-AAV-CR was successfully constructed, and a recombinant protein with a relative molecular mass of 17000 was obtained. The purified protein induced the production of antibodies against the conserved regions of AAV capsid in rabbits, and the titer of the purified antibodies reached 1:320 000. The antibodies were capable of recognizing a wide range of capsid protein sequences of AAV1-AAV10.@*CONCLUSION@#We successfully obtained the polyclonal antibodies against AAV capsid conserved region protein from rabbits, which facilitate future studies of AAV vector development and the biological functions of AAV.

Avaliação da resposta de anticorpos IgG contra diferentes variantes alélicas do Antígeno 1 de Membrana Apical (AMA-1) de Plasmodium vivax em indivíduos de áreas endêmicas de malária / Evaluation of IgG antibody response against different variants of Plasmodium vivax apical membrane antigen 1 (AMA-1) in individuals from malaria endemic areas

O Plasmodium vivax é a espécie com maior distribuição geográfica no mundo e a que predomina nas Américas, incluindo o Brasil. Comparado ao Plasmodium falciparum, poucas vacinas contra o P. vivax encontram-se em fase de testes clínicos. Um dos antígenos de formas sanguíneas de P. vivax candidato a vacina é o Antígeno 1 de Membrana Apical (PvAMA-1). Entretanto, a diversidade antigênica do mesmo na natureza representa um grande desafio para seu uso no desenvolvimento de uma vacina de ampla cobertura. No presente estudo, avaliamos se os polimorfismos de sequências já descritos são capazes de influenciar na eficácia de uma vacina baseada em PvAMA-1. Para isso, geramos 9 proteínas recombinantes a partir da levedura Pichia pastoris, as quais são representativas de diferentes variantes alélicas do antígeno PvAMA-1, a saber: Belem, Chesson I, Sal-1, Indonesia XIX, SK0814, TC103, PNG_05_ESP, PNG_62_MU e PNG_68_MAS. Após expressão e purificação das proteínas selecionadas, avaliamos comparativamente por ELISA a resposta de anticorpos IgG naturalmente adquiridos em indivíduos expostos a malária, procedentes da Região Amazônica. Todas as proteínas foram obtidas com rendimento e pureza apropriados para os estudos propostos. A prevalência total de indivíduos expostos a malária com anticorpos contra PvAMA-1 Belem foi de 53,68%, em 611 amostras de soro testadas. Entre 100 das amostras sorologicamente positivas para PvAMA-1 Belem, os maiores valores de DO492 foram obtidos para as variantes Chesson I, SK0814 e Sal-1, sugerindo que epítopos comuns ou de reatividade cruzada estão sendo reconhecidos nessas variantes. Por outro lado, níveis mais baixos de DO492 foram obtidos para as variantes Indonesia XIX, TC103, PNG_05_ESP, PNG_62_MU e PNG_68_MAS, o que pode significar que essas variantes são menos prevalentes ou não circulam no Brasil. Soros policlonais de camundongos C57BL/6 previamente imunizados com PvAMA-1 Belem foram testados quanto ao reconhecimento das diferentes variantes por ELISA. Nossos resultados demonstraram que as variantes Chesson I, Indonesia XIX, SK0814, Sal-1 e a proteína homóloga foram predominantemente reconhecidas. Por fim, ensaios de competição baseados em ELISA revelaram que as proteínas Chesson I, Indonesia XIX, SK0814 e Sal-1, na fase solúvel, foram capazes de inibir a ligação de anticorpos à variante Belem aderida a placa, sugerindo a presença de epítopos comuns ou de reatividade cruzada entre as mesmas. Nossos dados sugerem que uma vacina baseada na variante PvAMA-1 Belem gera anticorpos variante-transcendentes. Entretanto, para gerar uma vacina universal baseada em PvAMA-1, uma formulação multi-alélica, incluindo variantes da Tailândia e Papua Nova Guiné, deverão ser testadas

Plasmodium vivax has the largest geographical distribution Plasmodium species in the world, and is predominant in the Americas, including Brazil. Fewer P. vivax vaccines than P. falciparum vaccines have successfully reached clinical trials. One of the candidate antigens for a blood-stage P. vivax vaccine is the apical membrane antigen 1 (PvAMA-1). However, the high natural variability found in this antigen presents a major challenge for its development into a wide-range vaccine. In the present study, we evaluated whether sequence polymorphisms would influence a vaccine based on PvAMA-1. To achieve this, we generated 9 recombinant proteins from the yeast Pichia pastoris, representative of different allelic variants of the PvAMA-1 antigen: Belem, Chesson I, Sal-1, Indonesia XIX, SK0814, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS. After expression and purification of these proteins, we compared, by ELISA and IgG blocking, the natural acquired response from malaria-exposed individuals in the Amazon Region. All proteins selected had the appropriate yield and purity for the proposed studies. The total prevalence of malaria-exposed individuals with reactivity to PvAMA-1 Belem was 53,68%, from 611 serum samples tested. One hundred of these serologically positive samples were further tested against recombinant proteins representing the other allelic variants. The highest OD values resulted from Sal-1, Chesson I and SK0814 variants, suggesting that common epitopes or cross-reactivity exist across the variants. On the other hand, the lowest OD values resulted from the variants Indonesia XIX, TC103, PNG_05_ESP, PNG_62_MU, and PNG_68_MAS, which may mean these variants are less prevalent or do not circulate in Brazil. Polyclonal sera from C57BL/6 mice immunized with PvAMA-1 Belem were tested for recognition of different variants by ELISA. Our results showed that the variants Chesson I, Sal-1, Indonesia XIX, SK0814 and the homologous protein were predominantly recognized. Lastly, ELISA-based competition assays revealed that Chesson I, Sal-1, Indonesia XIX and SK0814 proteins were able to inhibit antibody binding to the Belem variant, suggesting the presence of common epitopes or cross-reactivity between these variants. Our data suggest that a vaccine based on the PvAMA-1 Belem variant displays strain-transcendent antibodies. However, to generate a universal vaccine based on PvAMA-1, a multiallelic formulation including variants from Thailand and Papua New Guinea must be tested

Murine models of primary biliary cholangitis and its role in disease research / 中国药理学通报

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by destructive cholangitis affecting the small intrahepatic bile ducts, and the presence of antimitochondrial antibodies (AMA). At present, there has been limited progress in exploring the pathogenesis of the disease, because of difficulty in obtaining human tissue samples and lack of suitable animal models. In recent years, some murine models have been reported, which showed serological, biochemical, and histological characteristics similar to those of humans with PBC. In this review, various murine models of PBC are reviewed, and the characteristics and mechanism of PBC in mice are introduced. Besides, their advantages and limitations in the study of PBC are discussed. It hopes to provide an important theoretical basis for studying the pathogenesis of PBC and developing therapeutic drugs for PBC.

About the necessity of including HoBi-like pestiviruses in bovine respiratory and reproductive viral vacines / Sobre a necessidade de incluir pestivírus HoBi-like em vacinas virais respiratórias e reprodutivas para bovinos

HoBi-like pestiviruses (HoBiPeV) constitute a novel group of bovine pestiviruses, genetically and antigenically related to bovine viral diarrhea virus 1 (BVDV-1) and BVDV-2. Recent data shows that HoBiPeV are endemic among Brazilian cattle, yet bovine reproductive/respiratory vaccines contain only BVDV-1 and BVDV-2 strains. The present study investigated the neutralizing antibody response against these pestiviruses induced by two commercial vaccines (VA = attenuated, VI = inactivated) and by three experimental, replicative, vaccine formulations (VAC1 = monovalent, BVDV-1; VAC2 = bivalent, BVDV-1 + BVDV-2; VAC3 = trivalent, BVDV-1 + BVDV-2 and HoBiPeV). Seronegative beef calves were immunized once (replicative vaccines) or twice (inactivated vaccine) and serum samples were tested by virus-neutralization (VN) 30 days after vaccination (dpv) (replicative vaccines) or 30 days after the second dose (VI). We considered a threshold VN titer of ≥60 indicative of protection against clinical disease. At 30 dpv, VA induced protective titers against BVDV-2 in 7/7 animals (GMT=289.8) and against BVDV-1 and HoBiPeV in 5/7 animals (GMTs=97.5 and 80, respectively). VI induced protective titers against BVDV-1 in 1/7 animal (GMT=16.4), 2/7 animals against BVDV-2 (GMT=53.8) and in none of the calves against HoBiPeV (GMT=12.2). When a pool of sera of each vaccine group was tested against individual Brazilian isolates, VA induced protective titers against 3/7 BVDV-1 isolates, to 9/10 (BVDV-2) and 1/8 (HoBiPeV); VI induced protective titers against 1/7 (BVDV-1), 1/10 (BVDV-2) and none (0/8) HoBiPeV isolates. The experimental vaccine VAC1 induced protective titers against BVDV-1 in 9/9 animals (GMT=320) but in no animal against BVDV-2 or HoBiPeV (GMT<10). VAC2 induced protective titers to BVDV-1 and BVDV-2 in 9/9 animals (GMTs=160 and 640, respectively), and against HoBiPeV in 7/9 animals (GMT=108.5). Finally, VAC3 induced protective titers in all animals against BVDV-1 (GMT=234.3), BVDV-2 (294.9) and HoBiPeV (201.1). Testing the pool of sera against pestivirus isolates, VAC1 induced titers ≥ 60 against 4/7 BVDV-1 but to none BVDV-2/HoBiPeV isolate; VAC2 induced protective titers against 4/7 BVDV-1; 10/10 BVDV-2 and 2/8 HoBiPeV; VAC3 induced protective titers against all BVDV-1, BVDV-2 and HoBiPeV isolates. These results indicate that vaccines composed by BVDV-1+BVDV-2, especially those containing inactivated virus, may not induce serological response against a variety of HoBiPeV isolates. Thus, the need of inclusion of HoBiPeV in vaccine formulations should be considered.(AU)

Os pestivírus HoBi-like (HoBiPeV) compõe um grupo novo de pestivírus de bovinos, genética e antigenicamente relacionados com os vírus da diarreia viral bovina 1 e 2 (BVDV-1, BVDV2). Dados recentes indicam que os HoBiPeV são endêmicos na população bovina do Brasil, mas as vacinas respiratórias e reprodutivas bovinas contêm apenas cepas de BVDV-1 e BVDV-2. O presente estudo investigou a atividade neutralizante contra estes pestivírus induzidas por duas vacinas comerciais (VA = atenuada, VI = inativada) e por três vacinas experimentais replicativas (VAC1 = monovalente, BVDV-1; VAC2 = bivalente, BVDV-1 + BVDV-2; VAC3 = trivalente, BVDV-1 + BVDV-2 e HoBiPeV). Bezerros soronegativos foram imunizados uma vez (vacinas replicativas) ou duas (vacina inativada) e amostras de soro foram testadas por vírus-neutralização (VN) 30 dias após a vacinação (dpv) (vacinas replicativas) ou 30 dias após a segunda dose (VI). Títulos neutralizantes ≥60 foram considerados indicativos de proteção contra doença clínica. Nesta data, a VA induziu títulos protetivos contra o BVDV-2 em 7/7 animais (GMT=289,8) e contra BVDV-1 e HoBiPeV em 5/7 animals (GMTs=97,5 e 80, respectivamente). VI induziu títulos protetores contra BVDV-1 em 1/7 animal (GMT=16,4), em 2/7 animais contra BVDV-2 (GMT=53,8) e em nenhum contra HoBiPeV (GMT=12,2). Quando um pool de soro de cada grupo vacinal foi testado frente a isolados Brasileiros, a VA induziu títulos protetores contra 3/7 isolados de BVDV-1, 9/10 (BVDV-2) e 1/8 (HoBiPeV); VI induziu títulos protetores em 1/7 contra BVDV-1, 1/10 (BVDV-2) e em nenhum (0/8) contra isolados de HoBiPeV. A VAC1 induziu títulos protetores contra BVDV-1 em 9/9 animais (GMT=320) mas em nenhum animal contra BVDV-2 ou HoBiPeV (GMT<10). VAC2 induziu títulos protetores contra BVDV-1e BVDV-2 em 9/9 animais (GMTs=160 e 640, respectivamente),e contra HoBiPeV em 7/9 animais (GMT=108,5). Finalmente, VAC3 induziu títulos protetores em todos os animais contra BVDV-1 (GMT=234,3), BVDV-2 (294,9) e HoBiPeV (201,1). No teste de pool de soro contra isolados de pestivírus, VAC1 induziu títulos ≥60 contra 4/7 BVDV-1 mas contra nenhum isolado de BVDV-2/HoBiPeV; VAC2 induziu títulos protetores contra 4/7 BVDV-1; 10/10 BVDV-2 e 2/8 HoBiPeV; VAC3 induziu títulos protetores contra todos BVDV-1, BVDV-2 e HoBiPeV. Esses resultados indicam que vacinas contendo apenas BVDV-1 BVDV-2, especialmente aquelas inativadas, podem não conferir resposta sorológica protetora contra vários isolados de HoBiPeV. Portanto, a necessidade de se incluir cepas de HoBiPeV nas vacinas deve ser considerada.(AU)

Comparison of antigenic mutation during egg and cell passage cultivation of H3N2 influenza virus

Genetic evolution analysis of SARS-CoV-2 ORF 1ab/S/M protein and screening of epitopes of mRNA vaccine / 解放军医学杂志

Objective To analyze the genetic and evolutionary properties of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ORF 1ab/S/M proteins and select antigen epitope sequences of mRNA vaccines. Methods: We analyzed the worldwide SARS-CoV-2 genome sequences in this study and have focused on the protein and nucleic acid sequences of the ORF 1ab/S/M. The neighbor-joining tree was employed to map the global distribution of genetic differences. Based on current research on SARS-CoV-2 and SARS-CoV-2 genetic differences, we predicted candidate mRNA vaccines for SARS-CoV-2. Results: The SARS-CoV-2 ORF 1ab nucleic acid sequence similarity is 100.0%, while the homology is 99.3% in the global hot region; the S-protein nucleic acid sequence similarity is 100.0%, while the homology is 97.5%; the M-protein nucleic acid sequence similarity is 100.0%, while the homology is 99.9%. Global distribution of ORF 1ab/S/M proteins indicates that there is a significant genetic difference between the Americas and Eurasia. Potential vaccine antigen epitope mRNA sequences (11 B cell responses and 13 T cell responses) were selected for SARS-CoV-2 ORF 1ab protein; 6 B cell responses and 4 T cell responses antigen epitope mRNA sequences were selected for the Spike protein; 3 B cell responses and 7 T cell responses antigen epitope mRNA sequences were selected for the membrane protein. Conclusion: There are significant genetic differences in the global hot spot of SARS-CoV-2 in the Americas and Eurasia. Through our new antigen design strategy to screen linear epitopes, we predicted many sequences in ORF 1ab/S/M coding region that potentially raising an immune response. Our study will benefit the discovery of the mRNA vaccine (tandem antigen epitope sequence), antibody discovery, and potentially understanding related immune mechanisms.

Expression and purification of the transcription factor StMsn2 from Setosphaeria turcica in Escherichia coli

Background: In Saccharomyces cerevisiae, Msn2, which acts as a key transcription factor downstream the MAPKHOG cascade pathway, also regulates the expression of genes related to stress responses. However, little is known about the regulation mechanisms of the transcription factor in Setosphaeria turcica. Results: In this study, a zinc finger DNA-binding protein, designated as StMSN2, was cloned from S. turcica. Sequencing results showed that StMSN2 had a 1752 bp open reading frame (ORF), which was interrupted by an intron (135 bp) and encoded a putative 538-amino acid protein. Phylogenetic analysis further revealed that StMsn2 was more closely related to Msn2 of Aspergillus parasiticus. StMSN2 was cloned into the pET-28a vector with His (Histidine) tags and induced with 1 mM IPTG (isopropyl-ß-D-thiogalactoside) at 37°C. The recombinant His-tagged StMsn2 was purified, and a band of size approximately 58.8 kDa was obtained. The high specificity of the polyclonal antibody Msn2-2 was detected with the StMsn2 protein from S. turcica and prokaryotic expression system, respectively. Conclusions: A new gene, named StMSN2, with 1617 bp ORF was cloned from S. turcica and characterized using bioinformatics methods. StMsn2 was expressed and purified in a prokaryotic system. A polyclonal antibody, named Msn2-2, against StMsn2 with high specificity was identified.

Antigenic and genetic characteristics of influenza A(H1N1)pdm09 virus isolated in Sichuan province from 2018 to 2019 / 中华实验和临床病毒学杂志

Objective@#To understand the epidemiological characteristics of influenza A(H1N1)pdm09 virus in Sichuan population during the monitoring period of 2018-2019, and to clarify the antigenic variation, the gene characteristics and the matching of current epidemic strains, vaccine strains, representative strains at home and abroad.@*Methods@#A total of 118 strains of influenza A(H1N1)pdm09 virus isolated in Sichuan region influenza network laboratory from April 2018 to March 2019 were selected. The hemagglutination inhibition (HI) assay was conducted for antigen analysis. The HA and NA genes of 16 strains with low-response strains were sequenced. Phylogenetic analysis and amino acid locus variation analysis were applied using BioEdit and MEGA5.0 software.@*Results@#The result of the antigen analysis demonstrated that more than 95% of the A(H1N1) pdm09 influenza viruses detected were similar to the WHO recommended vaccine strain A/Michigan/45/2015. The analysis of HA gene characteristics showed that some low-response strains had amino acid site variation in the Sa, Sb and Cb regions of the HA protein. A total of 15 low-response strains belonged to the 6B.1 branch. And their evolutionary relationship were close to the representative strains A/beijin-xicheng/SWL1633/2018 and A/brisbane/02/2018, which were popular at home and abroad. Compared with A/sichuan/1/2009, there are mutations involving 6, 14 and 1 amino acid sites in the antigen-determining regions (Sa, Sb, Ca and Cb), non-determined regions and receptor binding site(RBS) respectively. No amino acid site mutations related to resistance to NA gene were found.@*Conclusions@#In 2018-2019, the epidemic A(H1N1) pdm09 influenza virus in Sichuan is consistent with the global epidemic characteristics, which also matched with vaccine strains recommended by WHO in the northern hemisphere. Compared with A/sichuan/1/2009 which was the first isolated in China in 2009, there were amino acid sites mutations in antigen-determining region and receptor binding site of the HA protein, and the transmembrane region of the NA protein, drug and antibody binding sites.

Original antigenic sin in the influenza vaccination and its influence / 中华预防医学杂志

Original antigenic sin may exist in the influenza virus infection or vaccination, which possibly reduces the protective efficacy in repeated influenza vaccination. This paper reviews the literature on the original antigenic sin and its influence in influenza vaccination, and interprets the possible mechanism of this phenomenon from the three aspects of influenza virus structure, humoral immunity and cellular immunity. A large number of studies have shown that original antigen sin has a negative impact on influenza vaccination, but the evidence disproveing this phenomenon also exist, so multi-center large-scale clinical trials should be conducted to provide evidence-based basis for reaearching whether original antigen sin exists and its effects. in order to provide reference for the development and update of noval influenza vaccines and its formulation of immunization strategies.

Genetic characterization of influenza A virus and assessment of vaccine efficacy in Yantai from 2014 to 2017 / 中华预防医学杂志

In this study, the swabs were collected among patients with an influenza-like illness (ILI) admitted to 2 sentinel surveillance hospitals of Yantai from April 2014 to August 2017. All specimen were cultured and identified by hemagglutination inhibition assay. Complete sequences of Hemagglutinin (HA) of influenza A were amplified, sequenced and analyzed using molecular and phylogenetic methods. The potential vaccine efficacy were calculated using Pepitope model. The results showed that the antigenicity of A (H3N2) had changed greatly. 8 strains of influenza A (H1N1) pdm09 belonged to subclade 6B.1 and 14 strains clustered in 6B.2. 12 strains of influenza A (H3N2) fell into subgroup 3C.3a and 33 strains clustered in 3C.2a. Several residues at antigen sites and potential glycosylation sites had changed in influenza A strains. Vaccine efficacy of influenza A (H1N1) pdm09 in 2015/2016 and 2016/2017 seasons were 77.29% and 79.11% of that of a perfect match with vaccine strain, meanwhile vaccine efficacy of influenza A (H3N2) in 2014/2015, 2015/2016 and 2016/2017 were-5.18%, 16.97% and 42.05% separately. In conclusion, the influenza A virus circulated in Yantai from 2014 to 2017 presented continual genetic variation. The recommended vaccine strains still afforded protection against influenza A (H1N1) pdm09 strains and provided suboptimal protection against influenza A (H3N2) strains.

Construction of recombinant influenza virus carrying human metapneumovirus epitopes / 中华微生物学和免疫学杂志

Objective To construct and rescue recombinant influenza virus strains expressing hu-man metapneumovirus ( hMPV) epitopes. -ethods B cell, CTL and Th epitopes predicted by bioinformat-ics software were coupled together in different combinations. These different array genes were inserted into the NS1 gene of influenza virus strain A/PR/8/34 ( PR8 ) , respectively. Recombinant PR8 influenza virus vectors expressing different hMPV antigenic epitopes were rescued by reverse genetics using eight-plasmid system. Sequencing analysis was conducted to verify whether the rescued viruses carried the chimeric hMPV epitopes. Hemagglutination ( HA) titers, half tissue culture infection dose ( TCID50 ) and growth curves were detected. Results Interval sequences GPGPG and KK were introduced into hMPV epitope combinations to construct multi-epitope antigens (MEA). These MEA were inserted into the PR8 NS gene, respectively. Using 8 plasmid system, three recombinant influenza virus strains were rescued successfully. After cultured for three passages in Madin-Darby canine kidney ( MDCK) cells and one in eggs, these three recombinant strains could proliferate steadily. Whole genome sequencing verified that the three recombinant strains car-ried the chimeric MEA sequences, named as rFLU/hMPV/B, rFLU/hMPV/CTL-Th and rFLU/hMPV/B-Th. HA titers of the recombinant strains were 128, 128 and 256 using turkey erythrocyte, respectively. Their TCID50 were 107. 0/ml, 106. 8/ml and 107. 0/ml, respectively. Growth curve tests also verified that the recombinant strains could proliferate steadily in MDCK cells. Conclusions Three recombinant influenza vi-rus vector strains carrying the B cell, CTL and Th epitopes of hMPV were rescued successfully. This study lays the foundation for further evaluation of the immune effects of these recombinant viruses and their poten-tial application value in vaccine development.

Infuenza and Patients with Chronic Diseases and Elderly

@#Influenza is a highly contagious viral illness characterized by fever, cough, headache and myalgia. The influenza virus is a segmented ribonucleic acid (RNA) virus that can infect both humans and animals, and the capacity for reassortment when multiple viruses infect the same cell has led – and will continue to lead – to the development of novel pandemic influenza A viruses. The disease is generally self-limiting, although complications and deaths can occur, particularly in children < two years of age, adults >65 years of age, pregnant women, and immunosuppressed individuals. Specific antiviral therapy is available, including oseltamivir in Singapore, and is recommended for severe disease as well as those with higher likelihood for developing complications from influenza. In addition to hand hygiene and respiratory etiquette, antiviral prophylaxis may reduce the impact and burden of influenza in household and institutional settings. However, the primary means for preventing influenza is via annual vaccination in those above the age of two years. The influenza vaccine, while having variable efficacy depending on antigenic matching with circulating viruses each year, is safe and cost-effective at the population level.

Genetic Diversity of Plasmodium vivax in Clinical Isolates from Southern Thailand using PvMSP1, PvMSP3 (PvMSP3α, PvMSP3β) Genes and Eight Microsatellite Markers

Plasmodium vivax is usually considered morbidity in endemic areas of Asia, Central and South America, and some part of Africa. In Thailand, previous studies indicated the genetic diversity of P. vivax in malaria-endemic regions such as the western part of Thailand bordering with Myanmar. The objective of the study is to investigate the genetic diversity of P. vivax circulating in Southern Thailand by using 3 antigenic markers and 8 microsatellite markers. Dried blood spots were collected from Chumphon, Phang Nga, Ranong and, Surat Thani provinces of Thailand. By PCR, 3 distinct sizes of PvMSP3α, 2 sizes of PvMSP3β and 2 sizes of PvMSP1 F2 were detected based on the length of PCR products, respectively. PCR/RFLP analyses of these antigen genes revealed high levels of genetic diversity. The genotyping of 8 microsatellite loci showed high genetic diversity as indicated by high alleles per locus and high expected heterozygosity (H(E)). The genotyping markers also showed multiple-clones of infection. Mixed genotypes were detected in 4.8% of PvMSP3α, 29.1% in PvMSP3β and 55.3% of microsatellite markers. These results showed that there was high genetic diversity of P. vivax isolated from Southern Thailand, indicating that the genetic diversity of P. vivax in this region was comparable to those observed other areas of Thailand.

Antigenic and immunogenic properties of the canine distemper virus nucleocapsid protein expressed in Escherichia coli employing codon optimized synthetic gene / Propriedades antigênicas e imunogênicas da proteína do nucleocapsídeo do virus da cinomose canina expressa em Escherichia coli empregando gene sintético com codons otimizados

Despite common occurrence and importance of canine distemper disease the majority of tests currently available for diagnosis are hampered by either low sensitivity or specificity. In this study it was evaluated antigenic and immunogenic characteristics of a conserved region of nucleocapsid protein of canine distemper virus (rCDV NP) expressed in Escherichia coli employing a codon optimized synthetic gene. The expression of rCDVNP in Star strain (mean 300μg/mL, purified) was confirmed by SDS-PAGE and Western blot analysis by using His-Tag monoclonal antibodies. Western blot and ELISA, employing positive and negative control dog sera, demonstrated the rCDVNP antigenicity. The rCDVNP was inoculated in hens and immunoglobulin Y (IgY) was purified from the egg yolk. The mean yield of IgY was 28.55mg/mL. IgY reacted with the recombinant protein as demonstrated by Western blot and ELISA assays. In summary, our findings demonstrated that rCDVNP is antigenic since CDV positive dog sera recognized the protein in vitro. Additionally, the rCDVNP proved to be immunogenic in hens being possible to isolate a high concentration of specific IgY antibodies from the egg yolk. Taken together, these results indicate that the rCDVNP along with the specific IgY could be useful tools for development of the canine distemper immunodiagnostic assays.(AU)

Apesar da ocorrência comum e importância da cinomose canina, a maioria dos testes atualmente disponíveis para diagnóstico são prejudicados pela baixa sensibilidade ou especificidade. Neste estudo foram avaliadas características antigênicas e imunogênicas de uma região conservada da proteína do nucleocapsídeo do virus da cinomose canina (rCDV NP) expressa em Escherichia coli empregando um gene sintético e codons otimizados. A expressão na cepa Star (média de 300μg/mL, purificada) foi confirmada por SDS-PAGE e Western blot utilizando anticorpos monoclonais anti-His-Tag. A antigenicidade da rCDVNP foi demonstrada por western blot e ELISA empregando soros de cães positivos e negativos. A rCDVNP foi inoculada em galinhas e imunoglobulina Y (gY) foi obtida e purificada a partir da gema. A produção média de IgY foi 28.55mg/mL. Anticorpos IgY reagiram com a proteína recombinante, quando analisados por Western blot e ELISA. Em resumo, nossos achados demonstram que a rCDVNP produzida é antigênica, uma vez que os anticorpos de soro de cães positivos para CDV reconheceram a proteína in vitro. Além disso, a rCDVNP foi imunogênica em galinhas, sendo possível isolar anticorpos IgY específicos a partir da gema do ovo em altas concentrações. Tomados em conjunto, estes resultados indicam que a rCDVNP juntamente com a IgY específica podem ser ferramentas úteis para elaborar ensaios de imunodiagnóstico de cinomose canina.(AU)