Qianqian Cui

Background: Herpes zoster (HZ), caused by the reactivation of varicella-zoster virus (VZV), primarily affects elderly populations worldwide. Although current recombinant HZ vaccines show strong immunogenicity, their high cost and potential side effects may limit their widespread use. Therefore, developing a cost-effective HZ vaccine with improved safety profiles would have significant clinical and public health implications. Methods: Building upon our previously optimized truncated gE (tgE350) from VZV, we developed the tgE350 + Fe nanoparticle vaccine using SpyTag/SpyCatcher covalent conjugation. The tgE350 protein (with a SpyTag tag) and the Fe protein (with a SpyCatcher tag) were expressed in HEK293F and E. coli BL21, respectively, enabling spontaneous nanoparticle assembly. Protein expression and nanoparticle formation were confirmed through SDS-PAGE and negative-stain electron microscopy. BALB/c mice were inoculated with either tgE350 + Fe or tgE350 combined with Al and CpG adjuvants. Immune responses were evaluated using ELISpot and flow cytometry for cellular immunity, along with ELISA, VZV microneutralization, and fluorescent antibody membrane antigen (FAMA) assays for antibody titers. Histopathological examination of major organs ensured vaccine safety. Results: Compared with the truncated vaccine tgE350, the nanoparticle vaccine tgE350 + Fe significantly enhanced VZV neutralizing antibodies and specific antibody responses in mice without causing significant changes in lymphocyte populations (no difference from the control group). Moreover, the tgE350 + Fe group had significantly more lymphocytes secreting IFN-γ, IL-2, and IL-4 than the tgE350 group. No apparent pathological damage was observed in the heart, liver, spleen, or lungs of mice in any experimental group. Conclusions: This experiment successfully developed the HZ nanoparticle vaccine tgE350 + Fe. It enhanced VZV-specific neutralizing antibodies, generated better cellular and humoral immune responses, and demonstrated good safety.

This study investigates the codon usage characteristics of Japanese encephalitis virus (JEV) genotype 5 (G5). Based on 339 complete JEV genome sequences, we systematically compared the codon usage patterns of G5 with other genotypes (G1–G4) using a multi-faceted approach, including evolutionary analysis, nucleotide composition, Relative Synonymous Codon Usage (RSCU), Principal Component Analysis (PCA), Effective Number of Codons Plot analysis (ENC-Plot), Parity Rule 2 analysis (PR2), Neutrality plot analysis, dinucleotide abundance analysis and Codon Adaptation Index analysis (CAI). The results indicate that G5 forms a distinct evolutionary branch, with both its overall GC content (50%) and GC content at the third codon position (GC3, 53%) being lower than those of other genotypes. RSCU analysis revealed a preferential use of A/U-ended codons in G5, indicating a trend towards reduced GC3 usage. ENC analysis demonstrated a stronger codon usage bias in G5 (mean ENC = 54.2). Furthermore, ENC-plot, PR2, and neutrality plot analyses collectively suggested that G5 is subject to stronger natural selection pressure. Analysis of dinucleotide abundance showed a significant increase in CA values in G5, while CAI analysis indicated higher translational efficiency in human hosts compared to Culex mosquito hosts. Our findings suggest that G5 JEV, potentially through reduced Cytosine-phosphate-Guanine (CpG) usage and optimized codon preference, may enhance its capabilities for immune evasion and host adaptation, and could possess the potential for efficient replication in humans or other mammalian hosts. This research provides crucial theoretical insights into the molecular evolutionary mechanisms of G5 JEV and informs related vaccine development.

During the 2023 surveillance of mosquito-borne viruses in Ningxia Hui Autonomous Region, a strain of Umatilla virus (UMAV) was isolated from a pool of Culex pipiens pallens (NX23166) collected in Xiji County and cultured in C6/36 cells. Electron microscopy revealed that NX23166-infected mosquito cells showed approximately 70-nm virus particles, typical of the genus Orbivirus. Through next-generation sequencing, 10 double-stranded RNA (dsRNA) segments of the virus were obtained. Phylogenetic and homology analyses based on these sequences revealed that this strain was most closely related to the first Chinese isolate from Yunnan in 2013 (DH13M98) and an Australian isolate from 2015 (M4941_15). However, the VP3 protein of this strain showed the closest evolutionary relationship to a German isolate from 2019 (ED-I-205-19), with an amino acid sequence identity of 94.00%. In contrast, the identity of the VP3 protein to that of other strains ranged only from 47.38% to 51.49%, suggesting that these two strains may belong to the same serotype. Nevertheless, this hypothesis needs to be further verified by a serum neutralization test. Furthermore, transcriptome sequencing analysis showed that infection with the Ningxia isolate of UMAV induced significant temporal transcriptomic reprogramming in C6/36 cells. This reprogramming was characterized by early activation of innate immune responses such as the Toll signaling pathway and autophagy, followed by significant suppression of metabolic pathways, including oxidative phosphorylation in the mid to late stages of infection, demonstrating a molecular phenotype of coordinated immune activation and metabolic suppression. These results provide new insights into the genetic diversity and geographic distribution of the species UMAV.

Japanese encephalitis (JE), a mosquito-borne viral disease caused by the Japanese encephalitis virus (JEV), remains a significant public health threat in Asia. Although vaccination programs have successfully reduced the incidence of JE, challenges persist in the adult population, and the emergence of rare JEV genotypes poses additional risks. In this study, a phylogenetic analysis of the whole JEV genome sequence, along with a temporal–spatial analysis of isolates and a host–vector analysis, was used to examine the changes in JEV transmission dynamics before and after 2012. The results revealed persistent differences between the dominant G1 and G3 genotypes, as well as the re-emergence of G4 and G5 genotypes. Although JEV has been detected in non-traditional vectors and atypical mammalian hosts, Culex tritaeniorhynchus and pigs remain the primary vector and amplifying host, respectively. These findings underscore the need to enhance existing JEV genotype surveillance while addressing emerging threats from genotype diversity, host expansion, and geographic spread.

Tick-borne encephalitis virus (TBEV) is a significant tick-borne flavivirus responsible for severe human diseases. Here, we analyzed the genetic diversity and evolutionary dynamics of TBEV using 263 genome sequences from the NCBI database and identified key amino acid mutations. TBEV sequences were classified into five genotypes—Baikalian, European, Far-Eastern, Himalaya, and Siberian—showing ORF nucleotide similarity of 81.5% to 88.0% and amino acid similarity of 93.0% to 96.4%. Extensive recombination between genotypes was not observed. Entropy analyses revealed highly variable sites distributed across the Baikalian (n = 2), European (n = 3), Far-Eastern (n = 5), and Siberian (n = 13) genotypes. Each genotype exhibited specific amino acid mutations. Positive selection analysis identified sites under selection in the full dataset (n = 2), as well as in the European (n = 6), Far-Eastern (n = 7), and Siberian (n = 4) genotypes. By integrating highly variable sites, shared genotype-specific mutations, and positively selected sites, we identified 37 key amino acid positions, primarily located on the surfaces of viral proteins. These positions may have a potential impact on protein function and pathogenicity, though further studies are required to validate and evaluate these effects comprehensively. This study provides the first comprehensive analysis of mutational landscapes across TBEV genotypes, uncovering potential critical mutations that may shape viral biology and pathogenicity, and offers valuable insights for further exploration of TBEV characteristics.

Backgrounds: A contemporary public health challenge is the increase in the prevalence rates of herpes zoster (HZ) worldwide. Methods: In this work, the gE gene structure was analyzed using bioinformatics techniques, and three plasmids of varying lengths, tgE537, tgE200, and tgE350, were expressed in Chinese hamster ovary (CHO) cells. These proteins were used to immunize BALB/c mice with Al/CpG adjuvant; ELISPOT and FCM were used to evaluate cellular immunity; and ELISA, VZV microneutralization, and FAMA assays were performed to detect antibody titers. Results: Target protein concentrations of 1.8 mg/mL for tgE537, 0.15 mg/mL for tgE200 and 0.65 mg/mL for tgE350 were effectively produced. The ability of the three protein segments to stimulate CD4⁺ and CD8⁺ T cells, as well as to cause lymphocytes to secrete IFN-γ and IL-4, did not significantly differ from one another. Both tgE537 and tgE350 were capable of generating VZV-specific antibodies and neutralizing antibodies, while tgE350 had the highest neutralizing antibody titer (4388). There was no equivalent humoral immune response induced by tgE200. Conclusions: The results of this investigation provide the groundwork for the creation of HZ recombinant vaccines using truncated proteins as antigens.

Wuxiang virus (WUXV) is the first sandfly-borne Phlebovirus isolated from Phlebotomus chinensis collected in China and has been established as a consistent viral presence in the local sandfly populations of both Wuxiang County and Yangquan City. However, its distribution in the Shanxi Province remains unclear. In this study, three novel WUXV strains were isolated from sandflies collected from Jiexiu City, Shanxi Province, China, in 2022. Subsequently, whole-genome sequences of these novel strains were generated using next-generation sequencing. The open reading frame (ORF) sequences of the WUXV strains from the three locations were subjected to gene analysis. Phylogenetic analysis revealed that WUXV belongs to two distinct clades with geographical differences. Strains from Wuxiang County and Yangquan City belonged to clade 1, whereas strains from Jiexiu City belonged to clade 2. Reassortment and recombination analyses indicated no gene reassortment or recombination between the two clades. However, four reassortments or recombination events could be detected in clade 1 strains. By aligning the amino acid sequences, eighty-seven mutation sites were identified between the two clades, with seventeen, sixty, nine, and one site(s) in the proteins RdRp, M, NSs, and N, respectively. Additionally, selection pressure analysis identified 17 positively selected sites across the entire genome of WUXV, with two, thirteen, one, and one site(s) in the proteins RdRp, M, NSs, and N, respectively. Notably, sites M-312 and M-340 in the M segment not only represented mutation sites but also showed positive selective pressure effects. These findings highlight the need for continuous nationwide surveillance of WUXV.