The diversity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine platforms and widespread natural exposure have created a complex landscape of humoral immunity requiring detailed characterization. Here, we compare nucleocapsid (N)- and spike (S)-specific antibody responses in sera from infected humans (IH) during the first pandemic wave (April-August 2020) and in vaccine recipients (Sinopharm, Sinovac, or AstraZeneca) using commercial ELISA kits. Among naturally IH, the IgG-positivity rate was higher for N (80.9%) than S (42.8%), with significantly elevated N-specific IgG levels compared to prepandemic controls (p-value <0.05), while IgM responses showed no significant differences. Strong positive correlations were observed between S- and N-specific antibody responses, particularly for IgG and its subclasses. Vaccinated cohorts exhibited high IgG positivity rate (83-100%) against both antigens with low IgM levels, and overall IgG and subclass responses were significantly elevated relative to pre-pandemic controls (p-value <0.05), with consistently strong inter-antigen correlations across groups. Overall, natural infection induces a coordinated humoral response biased toward the nucleocapsid antigen, supporting its utility as a marker of recent infection, whereas vaccination elicits a robust multi-subclass antibody response with platform-dependent differences in antigen recognition and subclass distribution.
It is widely known that numerous enveloped viruses can produce multinucleated cells (syncytia) as a result of viral entry-related membrane fusion events. By protecting the virus from the host's immune reaction, these syncytia are thought to promote viral reproduction. Syncytia are collections of merged cells. A viral spike protein (S) on the surface of an infected cell interacts with receptors on nearby cells to cause the syncytia response. The innate immune system's response to viruses affects how syncytia form. Some interferon-stimulated genes change the membrane in a way that reduces the likelihood of fusion. The severe acute respiratory syndrome coronavirus (SARS-CoV-2) virus is quickly changing; also, several mutations occurred in its S protein. Individually and together, the Alpha, Beta, Gamma, and Delta variants carry mutations that significantly affect S function and syncytia formation. The function of syncytia in newly emerging variant diseases is still unknown, though. Syncytia could cause disease through promoting viral transmission, cytopathicity, immunological evasion, and inflammatory responses. The SARS-CoV-2 S protein variations include several changes that improve receptor interactions, fusogenicity, and antibody reactivity. A wide range of clinical symptoms, including moderate febrile sickness, severe respiratory distress, and occasionally deadly lung damage, can be brought on by an infection with SARS-CoV-2. Several of these lung illnesses (MERS-CoV) are linked to both the Middle East Respiratory Syndrome (MERS) and the severe acute respiratory syndrome coronavirus (SARS-CoV). Compared to acute respiratory syndromes, the lung thrombosis brought on by Coronavirus disease 2019 (COVID-19) is incredibly severe. In this review we focused on innate immunological elements that prevent syncytia from forming and the molecular triggers of S-mediated fusion.
Mammalian reoviruses are promising oncolytic agents, but most preclinical and clinical work has focused on the type 3 Dearing (T3D) prototype, potentially underestimating the therapeutic relevance of broader reovirus genetic diversity. Because reoviruses possess a segmented double-stranded RNA genome, reassortment can generate progeny with novel combinations of traits influencing infectivity, replication, and cytotoxicity. Here, we evaluated a panel of previously generated T1L × T3D reassortants and recombinant reoviruses across three epithelial tumor models: A549 lung adenocarcinoma and the oral squamous carcinoma cell lines OECM-1 and CAL-27. Across all three models, the tested viruses displayed marked cell line-dependent heterogeneity in both cytotoxicity and infectivity. Several reassortants reduced viability more effectively than the parental T1L and T3D strains in one or more cell lines, and DB62 emerged as the most broadly active candidate across the panel. Infectivity and cytotoxicity overlapped only partially, indicating that efficient infection alone does not fully predict oncolytic potency. Together, these findings show that reassortment can generate reoviruses with enhanced or selective activity across epithelial tumor contexts and support future studies examining how segment-dependent differences in interferon antagonism, entry, and cell death shape oncolytic potency.
Background:The ongoing spillover of highly pathogenic avian influenza H5N1 virus into mammalian species, including recent outbreaks in dairy cattle, underscores an urgent need for broadly effective therapeutics. Nanobody, the variable domain of heavy chain-only antibody, offers unique advantages for viral neutralization due to its small size, stability, and accessibility to cryptic epitopes.Methods:In this study, we isolated a human nanobody, nAb35, targeting the hemagglutinin of the dairy cattle H5N1 virus A/Texas/37/2024 (clade 2.3.4.4b) via phage display of a human nanobody library. After three rounds of panning against the recombinant H5 ectodomain, a dominant clone (nAb35) was highly enriched. Then nAb35 was fused with a human IgG1 Fc fragment and expressed as a bivalent dimer.Results:Biochemical characterization demonstrated that nAb35 specifically binds to H5 under both denaturing and native conditions and recognizes a linear epitope accessible on H5 expressed on the cell surface. In vitro neutralization assays using H5 pseudovirus showed that nAb35 inhibited viral entry with a half-maximal effective concentration of approximately 10 μg/mL, as determined by both luciferase reporter and immunofluorescence assays.Conclusion:These findings identify nAb35 as a promising candidate for further therapeutic development against emerging H5N1 virus.
Rustrela virus (Rubivirus strelense) is a single-stranded, non-segmented RNA virus that causes brain diseases in animals, especially encephalitis and meningoencephalitis. Its rapidly mutating RNA genome complicates control, making a vaccine imperative. Immunoinformatics approaches were employed to make the polyepitope vaccine (PEV) for RuV control. Epitopes for cytotoxic T lymphocytes (CTL), helper T lymphocytes (HTL), and B cells were made from most immunogenic parts i.e., E1, E2, and capsid structural proteins of RuV. Epitopes that were antigenic, not allergic, IFN simulators, and not toxic were selected. This led to the selection of 6 CTL, 6 HTL, and 13 B cell epitopes, which were then used to construct the PEV with appropriate linkers and CTB as an adjuvant for immunological modulation. The physiochemical analyses demonstrated that the PEV was safe, stable, hydrophilic, and soluble. The secondary structure prediction has indicated mostly coiled and alpha helix in the PEV. The 3D scans revealed a solid and stable structure. The interactions and stability between the vaccine, TLR3, TLR4, and TLR7 were revealed by molecular docking. The vaccine candidate's minimal deformability and high stability were verified by molecular dynamics modeling. The developed PEV vaccine demonstrated a strong immunological response in in silico immune simulation. RuV-PEV is predicted to be efficiently produced in E. coli following in silico codon optimization and vector cloning. It elicited strong antigen-specific humoral and cellular responses, indicating promise as a Rustrela virus vaccine. Its precise effectiveness, safety, and immunogenicity profile may be confirmed by further experimental validations.
