Publications by authors named "Xinyan Zhai"

The continuous evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evaded the efficacy of previously developed antibodies and vaccines, thus remaining a significant global public health threat. Therefore, it is imperative to develop additional antibodies that are capable of neutralizing emerging variants. Nanobodies, as the smallest functional single-domain antibodies, exhibit enhanced stability and penetration ability, enabling them to recognize numerous concealed epitopes that are inaccessible to conventional antibodies.

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African swine fever virus (ASFV) infection causes African swine fever (ASF), a highly contagious and fatal disease that poses severe threat to swine production. To gain insights into the host responses to ASFV, we generated recombinant adenovirus Ad5 expressing viral membrane proteins p54, p17, and pB117L individually and infected an alveolar cell line, 3D4/21, with these recombinant viruses. Then, the cell lysates were analyzed using label-free quantification proteomic analysis method.

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African swine fever (ASF) caused by the African swine fever virus (ASFV) is a fatal and highly contagious disease of domestic pigs characterized by rapid disease progression and death within 2 weeks. How the immune cells respond to acute ASFV infection and contribute to the immunopathogenesis of ASFV has not been completely understood. In this study, we examined the activation, apoptosis, and functional changes of distinct immune cells in domestic pigs following acute infection with the ASFV CADC_HN09 strain using multicolor flow cytometry.

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Pseudorabies (PR) has been prevalent in Chinese swine breeding farms since the outbreak at the end of 2011. For investigating current prevalence of PR, a nationwide surveillance has been performed in this study. The swine serum samples were collected from 93, 100, 92, and 91 swine farms in China during 2013-2016, respectively.

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Background: NADC30-like strains of porcine reproductive and respiratory syndrome virus first appeared in Chinese swine herds in 2012.

Objective And Method: To explore the possible genetic diversity of these strains, we sequenced and analyzed the complete genomes of two NADC30-like strains. These isolates shared 95.

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Background: The recent emergence of NADC30-like porcine reproductive and respiratory syndrome virus (PRRSV) in vaccinated pigs arose more attentions for the high incidents of mutation and recombination of PRRSVs.

Findings: In this study, we determined full-length genome sequences of two NADC30-like PRRSV isolates from recent PRRSV outbreaks in China. Phylogenetic analysis showed that these two isolates were clustered in an independent branch together with NADC30, an American isolate in 2008.

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Porcine reproductive and respiratory syndrome (PRRS) is an emerging disease that has caused serious economic losses to the swine industry worldwide. In 2011, a nation-wide surveillance program investigated the prevalence of PRRS viruses (PRRSV) in Chinese breeding swine farms, and four European genotype PRRSV (PRRSV-Type 1) were successfully isolated. To explore the genetic diversity of PRRSV-Type 1 in China, these 4 viral strains were subjected to genome sequencing and analysis.

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The safety and efficacy of the JXA1-R vaccine, an attenuated strain of highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV), were examined using an intramuscular challenge model in piglets. The JXA1-R vaccine was obtained by passing HP-PRRSV JXA1 through Marc-145 cells (82nd passage). Genomic sequence comparisons showed that strain JXA1-R and its parental strain, JXA1, differ by 47 amino acids, and most of these differences are scattered throughout the PRRSV genome.

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Background: Parvoviruses are classified into two subfamilies based on their host range: the Parvovirinae, which infect vertebrates, and the Densovirinae, which mainly infect insects and other arthropods. In recent years, a number of novel parvoviruses belonging to the subfamily Parvovirinae have been identified from various animal species and humans, including human parvovirus 4 (PARV4), porcine hokovirus, ovine partetravirus, porcine parvovirus 4 (PPV4), and porcine parvovirus 5 (PPV5).

Methods: Using sequence-independent single primer amplification (SISPA), a novel parvovirus within the subfamily Parvovirinae that was distinct from any known parvoviruses was identified and five full-length genome sequences were determined and analyzed.

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In 2012, an unprecedented large-scale outbreak of disease in pigs in China caused great economic losses to the swine industry. Isolates from pseudorabies virus epidemics in swine herds were characterized. Evidence confirmed that the pathogenic pseudorabies virus was the etiologic agent of this epidemic.

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Here, we report a novel European genotype porcine reproductive and respiratory syndrome virus (PRRSV) strain with 15 nucleotide deletions in the nonstructural protein 2 region and 3 nucleotide deletions in the overlapping regions of the open reading frame 3 (ORF3) and ORF4 regions. This study will aid in further exploration of the genetic and antigenic diversity of the European genotype of the PRRSV in China.

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Porcine reproductive and respiratory syndrome virus (PRRSV) non-structural protein 7 (Nsp7) plays an important role in the induction of host humoral immune response and could serve as an ideal antigen for serological genotyping assay for PRRSV based on the significant difference in immunoreactivities of North American (NA) and European (EU) PRRSV Nsp7. In this study, Nsp7 of NA and EU PRRSVwas separately expressed and purified using prokaryotic expression system. The purified recombinant Nsp7 proteins reacted with serum antibodies against corresponding genotype PRRSV in Western blotting.

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Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) is a variant of type 2 PRRSV with high virulence. Genetic and pathogenic characteristics of HP-PRRSV vary rapidly during the evolution. In this study, we determined the complete genome of a HP-PRRSV isolate designated 10FUJ-2, which shared 98.

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Here, we report a novel porcine circovirus type 2a (PCV2a) strain with 11 nucleotides (nt) inserted in the origin of genome replication (Ori). This is the first report of a PCV2a strain with nucleotide insertion in Ori. Our study will help further epidemiological studies and extend our knowledge of evolutionary characteristics of PCV2.

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A highly pathogenic strain of porcine reproductive and respiratory syndrome virus (PRRSV), characterized by a discontinuous 30-amino-acid deletion in its Nsp2-coding region, has been emerging in China since 2006. Here, we report the complete genomic sequence of two novel Chinese virulent PRRSV variants with additional NSP2-gene deletions, which will help us understand the molecular and evolutionary characteristics of PRRSV in Asia.

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Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) initially emerged in China and currently prevails in other Asian countries as well, resulting in immense economic losses. HP-PRRS virus (HP-PRRSV) has undergone rapid evolution since its first recognition in 2006. To analyze the genomic and pathogenic characteristics of 2010 HP-PRRSV, we tested 919 clinical samples collected from China, Laos and Vietnam, sequenced 29 complete genomes of HP-PRRSV isolates, and determined the pathogenicity of seven HP-PRRS viruses isolated from 2006 to 2010.

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Porcine circovirus type 2 (PCV2) is continuously evolving through point mutation and genome recombination. In the present study, genetic affiliations of 40 PCV2 strains were determined by amplification, sequencing and phylogenetic analyses during the nationwide molecular epidemiology investigation from 2009 to 2010 in mainland China. The results revealed that PCV2b was the predominant genotype in mainland China from 2009 to 2010 and PCV2b-1C within PCV-2b genotype was an emerging predominant subtype.

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Porcine circovirus diseases (PCVD) are globally emerging diseases that have huge economic impacts on swine industry. Porcine circovirus type 2 (PCV2) is considered to be the essential primary causative agent of PCVD. In the present study, recombination analyses of PCV2 identified two possible recombination events with high confidence using recombination detection program, phylogenetic analysis and base-by-base comparison.

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A high-mortality swine disease, the highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS), reappeared in some regions of China in 2009. To explore the possible mechanisms underlying the emergence of HP-PRRSV and more fully understand the extent of the genetic diversity of this virus in China, the complete genome of 14 isolates from 10 provinces in China from 2009 were analyzed. Full-length genome sequencing analysis showed that the 14 isolates were closely related to HP-PRRSV, with 98.

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