Journal of Medical Virology最新文献

Current dengue vaccines remain limited by serotype-dependent efficacy and interference from preexisting anti-dengue immunity. We developed a novel multivalent fusion protein vaccine composed of three engineered dengue virus (DENV) components: a C-terminal truncated nonstructural protein 1 (ΔcNS1) to block NS1-mediated pathologic effects without harmful cross-reactivity, a consensus envelope protein domain III (cEDIII) to induce broad neutralizing antibodies, and an N-terminal truncated NS3 (ΔnNS3) to enhance cellular immune responses. In a murine dengue disease model, three-dose immunization with ΔcNS1–cEDIII–ΔnNS3 adjuvanted with Alum provides protection against all four DENV serotypes by significantly reducing viremia and prolonged bleeding time, with elicited robust antibody responses, enhanced cytotoxic activity of CD8⁺ T cells upon NS1/NS3 restimulation, and increased memory B and T cell populations. Notably, CpG oligodeoxynucleotides 1826 (CpG) plus Alum further enhanced immunogenicity, showing higher neutralizing activity, antigen-specific plasmablast expansion, and enhanced T cell functional activity, which was associated with more consistent improvement in protection-relevant outcomes compared with Alum alone. Importantly, two-dose immunization with CpG plus Alum-adjuvanted fusion protein conferred durable protection against the virulent DENV2 strain TW2015. These findings support this vaccine as a promising subunit candidate that addresses current limitations, offering both cross-serotype coverage and potential long-term efficacy.

The human metapneumovirus (HMPV) is a major respiratory pathogen mainly affecting infants under 5 years old. The interferon (IFN) response varies among patients, animal models, and HMPV strains, and this variation is crucial because the initial IFN response controls viral replication. Therefore, it is important to study the different profiles of IFN secretion during the same HMPV infection across various animal models. In this study, BALB/c and C57BL/6 mice were infected with a clinical A1 strain of HMPV-CZ0107, and at the endpoint, the expression of different types of IFN was measured. BALB/c mice showed significant weight loss and viral replication, while C57BL/6 mice exhibited notable neutrophil infiltration. Mice infected with BALB/c displayed significant secretion of all tested IFN types in all samples, whereas C57BL/6-infected mice showed significant secretion of IFN-α and IFN-γ only in the lungs. Additionally, infected BALB/c and C57BL/6 mice demonstrated different activation patterns of IFN-α- and IFN-γ-secreting natural killer (NK) cells, including both immature and mature cells. These findings characterize the IFN response induced by HMPV-CZ0107 and suggest that this infection results in higher secretion of IFNs in BALB/c mice compared to C57BL/6 mice, which may help explain the less severe clinical parameters observed in C57BL/6 mice.

In recent years, coronavirus, a kind of virus with a wide host range and high variability, has a large and complex genome. Research on the reverse genetics of coronaviruses has always been a hot spot. Coronavirus cannot only infect mammals, but also infect humans, showing its wide host adaptability. The mutation ability of the coronavirus is extremely strong. Recently, the rapid mutation rate of SARS-CoV-2 has made the development of vaccines and therapeutic methods face great challenges. At present, reverse genetics technology is a molecular biology tool. This process primarily involves cloning the full-length genome cDNA of the virus onto a vector, and then reproducing the modified progeny virus in the cell to achieve accurate modification of the virus's genetic characteristics. This technology can explore the external characteristics of mutants and the evolution of their traits through artificial operations, such as knockout and site-directed mutagenesis of specific genes, and then reveal the biological functions of genes. This article will review the research progress of the coronavirus reverse genetic operating system. In the past research, reverse genetics technology has made remarkable progress in the field of coronavirus research. Researchers have successfully constructed various reverse genetic systems for coronaviruses, including IBV, SARS-CoV-2, and MERS-CoV. In addition, the reverse genetic system has also been used to study the cross-species transmission capacity of the virus, which is of great significance for preventing possible future novel coronavirus epidemics.

Influenza D virus (IDV) was first isolated in 2011 from a swine with respiratory disease symptoms in the United States. Epidemiological and serological evidence suggests that cattle are the natural reservoir of IDV, with periodic spillover events to other animal hosts. This study investigated the seroprevalence of two IDV lineages, D/660 and D/OK, among cattle workers in Southern Italy between 2023 and 2024 to better characterize the zoonotic exposure risk in this occupational setting. A control group from the same geographical area was also included. Serum samples were tested by hemagglutination inhibition and virus neutralization (VN) assays. Overall, 42.9% (60/140) of cattle workers were positive at least to one of the two IDV lineages. Moreover, 39.3% (55/140) were positive for D/660 and 34.3% (48/140) for D/OK, with all but one positive result confirmed by VN assay. In the control group, tested only for D/660, a significantly higher seroprevalence was observed, with 65.0% (39/60) testing positive. These findings suggest that IDV exposure is not restricted to occupational settings involving direct contact with cattle and underscore the importance of incorporating IDV into current influenza surveillance programs.

Since 1998, enterovirus A71 (EV-A71) has caused several outbreaks in Taiwan with hundreds of severe cases and deaths. EV-A71 exhibits a high genome mutation rate, resulting in a diverse viral population, called quasispecies. However, the consequence of variations found in quasispecies with EV-A71 viral virulence remains elusive. In this study, we aim to analyze the viral genomes of severe and mild clinical isolates from 2012 EV-A71 outbreak. Clinical isolates underwent isolation, extraction, and amplification, then sent for next-generation sequencing (NGS) using Illumina MiSeq. Using bioinformatics tools, sequence variation analysis identified four distinct, statistical variations, located in the 5′-UTR, 2C, 3A, and 3D of EV-A71 isolates between severe and mild clinical cases. Two variants found in the 3A and 3D polymerase (3Dpol) region, respectively, were found to have higher proportions in severe cases. The 3Dpol variant protein showed reduced polymerase activity compared to wild-type polymerase. In contrast, the 3A mutant virus shows a higher replication rate and greater fitness in both RD and DLD-1 cells. With better growth rates and fitness, the EV-A71 3A-5286C (76S) variation has a greater ability to maintain the fast-replicating populations and may be correlated with the disease severity and virulence of EV-A71.

Kyasanur Forest Disease (KFD), commonly known as ‘monkey fever,’ is a highly neglected tropical disease caused by the Kyasanur Forest Disease Virus (KFDV). KFD is endemic to the Western Ghats of Karnataka, India, with seasonal outbreaks during December to June every year. As there is no standard treatment regime, KFD can be fatal with a mortality rate of 2%–10%. Currently, KFD is detected through a non-specific IgM-ELISA followed by RT-PCR, which often delays diagnosis, leading to increased disease severity and even death. To address this, we focused on developing a specific antigen-based KFD detection. The KFDV Envelope Domain III (EDIII) and Non-Structural 1 (NS1) proteins were chosen as detection markers, cloned, and expressed using pET28a(+) vector in BL-21 (Rosetta) E. coli and purified. These proteins were used to raise polyclonal antibodies in rabbits and the antibody titre was found to be 1:256 000 and 1:512 000 against rEDIII and rNS1 proteins, respectively. Importantly, these polyclonal antibodies showed no cross-reactivity against corresponding dengue virus EDIII and NS1 proteins. Using polyclonal antibodies against rEDIII, we developed sandwich ELISA for the specific detection of KFD, which has demonstrated high specificity and sensitivity. Further, anti-rEDIII polyclonal antibodies also detected full-length KFDV-E protein expressed in mammalian cells, confirming the antibody specificity for the native viral antigen.