Search

To determine the proportion of individuals with detectable antigen in plasma or serum after SARS-CoV-2 infection and the association of antigen detection with postacute sequelae of COVID-19 (PASC) symptoms. Plasma and serum samples were collected from adults participating in four independent studies at different time points, ranging from several days up to 14 months post-SARS-CoV-2 infection. The primary outcome measure was to quantify SARS-CoV-2 antigens, including the S1 subunit of spike, full-length spike, and nucleocapsid, in participant samples. The presence of 34 commonly reported PASC symptoms during the postacute period was determined from participant surveys or chart reviews of electronic health records. Of the 1569 samples analysed from 706 individuals infected with SARS-CoV-2, 21% (95% CI, 18–24%) were positive for either S1, spike, or nucleocapsid. Spike was predominantly detected, and the highest proportion of samples was spike positive (20%; 95% CI, 18–22%) between 4 and 7 months postinfection. In total, 578 participants (82%) reported at least one of the 34 PASC symptoms included in our analysis ≥1 month postinfection. Cardiopulmonary, musculoskeletal, and neurologic symptoms had the highest reported prevalence in over half of all participants, and among those participants, 43% (95% CI, 40–45%) on average were antigen-positive. Among the participants who reported no ongoing symptoms (128, 18%), antigen was detected in 28 participants (21%). The presence of antigen was associated with the presence of one or more PASC symptoms, adjusting for sex, age, time postinfection, and cohort (OR, 1.8; 95% CI, 1.4–2.2). The findings of this multicohort study indicate that SARS-CoV-2 antigens can be detected in the blood of a substantial proportion of individuals up to 14 months after infection. While approximately one in five asymptomatic individuals was antigen-positive, roughly half of all individuals reporting ongoing cardiopulmonary, musculoskeletal, and neurologic symptoms were antigen-positive. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EVs) released by virus-infected cells have the potential to encapsulate viral peptides, a characteristic that could facilitate vaccine development. Furthermore, plasma-derived EVs may elucidate pathological changes occurring in distal tissues during viral infections. We hypothesized that molecular characterization of EVs isolated from COVID-19 patients would reveal peptides suitable for vaccine development. Blood samples were collected from three cohorts: severe COVID-19 patients (G1), mild/asymptomatic cases (G2), and SARS-CoV-2-negative healthcare workers (G3). Samples were obtained at two time points: during the initial phase of the pandemic in early 2020 (m0) and eight months later (m8). Clinical data analysis revealed elevated inflammatory markers in G1. Notably, non-vaccinated individuals in G1 exhibited increased levels of neutralizing antibodies at m8, suggesting prolonged exposure to viral antigens. Proteomic profiling of EVs was performed using three distinct methods: immunocapture (targeting CD9), ganglioside-capture (utilizing Siglec-1) and size-exclusion chromatography (SEC). Contrary to our hypothesis, this analysis failed to identify viral peptides. These findings were subsequently validated through Western blot analysis targeting the RBD of the SARS-CoV-2 Spike protein's and comparative studies using samples from experimentally infected Syrian hamsters. Furthermore, analysis of the EV cargo revealed a diverse molecular profile, including components involved in the regulation of viral replication, systemic inflammation, antigen presentation, and stress responses. These findings underscore the potential significance of EVs in the pathogenesis and progression of COVID-19. [ABSTRACT FROM AUTHOR]

Epstein–Barr virus (EBV) is detected in nearly 100% of nonkeratinizing nasopharyngeal carcinoma (NPC) and EBV‐based biomarkers are used for NPC screening in endemic regions. Immunoglobulin A (IgA) against EBV nuclear antigen 1 (EBNA1) and viral capsid antigen (VCA), and recently identified anti‐BNLF2b antibodies have been shown to be the most effective screening tool; however, the screening efficacy still needs to be improved. This study developed a multiplex serological assay by testing IgA and immunoglobulin G (IgG) antibodies against representative EBV antigens that are highly transcribed in NPC and/or function crucially in viral reactivation, including BALFs, BNLF2a/b, LF1, LF2, and Zta (BZLF1). Among them, BNLF2b‐IgG had the best performance distinguishing NPC patients from controls (area under the curve: 0.951, 95% confidence interval [CI]: 0.913–0.990). Antibodies to lytic antigens BALF2 and VCA were significantly higher in advanced‐stage than in early‐stage tumors; in contrast, antibodies to latent protein EBNA1 and early lytic antigen BNLF2b were not correlated with tumor progression. Accordingly, a novel strategy combining EBNA1‐IgA and BNLF2b‐IgG was proposed and validated improving the integrated discrimination by 15.8% (95% CI: 9.8%–21.7%, p <.0001) compared with the two‐antibody method. Furthermore, we found EBV antibody profile in patients was more complicated compared with that in healthy carriers, in which stronger correlations between antibodies against different phases of antigens were observed. Overall, our serological assay indicated that aberrant latent infection of EBV in nasopharyngeal epithelial cells was probably a key step in NPC initiation, while more lytic protein expression might be involved in NPC progression. [ABSTRACT FROM AUTHOR]

Porcine dermatitis and nephropathy syndrome (PDNS) is a severe condition that affects mainly growing pigs and is considered to be caused by a type III hypersensitivity reaction. Although porcine circovirus 2 (PCV-2) is the antigen linked to this condition, porcine circovirus 3 (PCV-3) has also been proposed to be causally associated with PDNS. Moreover, the initial description of porcine circovirus 4 (PCV-4) also related this novel agent to this clinicopathological entity. Therefore, this retrospective study included a large number of PDNS cases (n = 102) fulfilling specific histologic criteria in search of known porcine circoviruses (PCV-1 to PCV-4) by conventional and/or quantitative PCR (qPCR). All the samples were subjected to PCV-2 immunohistochemistry (IHC) or conventional in situ hybridization (C-ISH), and RNAscope® (R-ISH) was used to study PCV-2 and PCV-3 localization in a subset of the samples. All PDNS cases were PCV-2 positive by qPCR, while 30 of them (29.4%) yielded PCV-3 qPCR positivity; PCV-2 viral loads were significantly greater than PCV-3 viral loads. All animals were negative for PCV-1 and PCV-4. By C-ISH/IHC, 63 cases (61.8%) were positive for PCV-2, with low to moderate amounts of antigen. R-ISH demonstrated higher sensitivity, as all studied cases were positive; however, neither PCV-2 nor PCV-3 were consistently found within characteristic PDNS lesions. These results indicate that all PDNS-affected pigs were infected with PCV-2, emphasizing the likelihood that this viral antigen is causally linked to this condition. In contrast, no evidence of the association of PCV-1, PCV-3 or PCV-4 with PDNS was found. [ABSTRACT FROM AUTHOR]

Infectious diseases remain a persistent public health problem and a leading cause of morbidity and mortality in both humans and animals. The most effective method of combating viral infections is the widespread use of prophylactic vaccinations, which are administered to both people at risk of disease and animals that may serve as significant sources of infection. Therefore, it is crucial to develop technologies for the production of vaccines that are highly effective, easy to transport and store, and cost-effective. The protein expression system based on the protozoan Leishmania tarentolae offers several advantages, validated by numerous studies, making it a good platform for producing vaccine antigens. This review provides a comprehensive overview into the potential applications of L. tarentolae for the safe production of effective viral antigens. [ABSTRACT FROM AUTHOR]

Increased use of antiviral monoclonal antibodies (mAbs) for treatment and prophylaxis necessitates better understanding of their impact on endogenous immunity to vaccines and viruses. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic presented an opportunity to study immunity in individuals who received antiviral mAbs and were subsequently immunized with vaccines encoding the mAb-targeted viral spike antigen. Here, we describe the impact of administration of an antibody combination, casirivimab plus imdevimab (CAS+IMD), on immune responses to subsequent SARS-CoV-2 vaccination in humans, nonhuman primates, and mice. The presence of CAS+IMD at the time of vaccination led to a specific diminishment of vaccine-elicited pseudovirus neutralizing antibody titers without overall dampening of spike protein–directed immune responses, including antibody, B cell, and T cell responses. The impact on pseudovirus neutralizing titers extended to other therapeutic anti–spike protein antibodies when used as either monotherapy or combination therapy. The specific reduction in pseudovirus neutralizing titers was the result of epitope masking, a phenomenon where specific epitopes are bound by high-affinity antibodies and blocked from B cell recognition. Encouragingly, this reduction in pseudovirus neutralizing titers was reversible with additional booster vaccination. Moreover, by assessing the antiviral immune response in SARS-CoV-2–infected individuals treated therapeutically with CAS+IMD, we demonstrated alteration of antiviral humoral immunity in those who had received mAb therapy, but only in those individuals who had yet to start mounting their natural immune response at the time of mAb treatment. Together, these data demonstrate that antiviral mAbs can alter endogenous humoral immunity during vaccination or infection. Editor's summary: Monoclonal antibody (mAb) therapies and vaccines were both essential tools for curbing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. As vaccines were rolled out during clinical trials for mAb therapies, it offered Petro et al. a unique opportunity to ask how SARS-CoV-2 mAb therapy influenced vaccine responses. The authors found that mAb therapy with casirivimab plus imdevimab, given at the time of vaccination, altered vaccine-elicited immunity in humans, resulting in lower neutralizing titers; this observation was mirrored in data from both nonhuman primates and mice. Encouragingly, booster vaccinations restored neutralizing antibody titers. A similar study in humans who received casirivimab plus imdevimab during SARS-CoV-2 infection revealed that early mAb treatment also impaired elicitation of endogenous immunity. Together, these data shed light on the complex interplay among mAb therapies, vaccines, and infections. —Courtney Malo [ABSTRACT FROM AUTHOR]

The SARS-CoV-2 pandemic has highlighted the challenges posed by the emergence and rapid global spread of previously unknown viruses. Early investigations on the pathogenesis of newly identified viruses are often hampered by a lack of appropriate sample material and conventional detection methods. In this study, viral replication within the lungs of SARS-CoV-2-infected Syrian golden hamsters was assessed by immunolabeling dsRNA intermediates with three different monoclonal antibodies in formalin-fixed, paraffin-embedded tissue samples. The presence of dsRNA was compared to viral antigen levels, viral titers, and genomic RNA replicates using three different variants of concern and an ancestral virus strain at a single time point and during the course of infection with an ancestral variant, and then validated using fluorescent 2-plex in situ hybridization. The results indicate that the detection of viral infection using anti-dsRNA antibodies is restricted to an early phase of infection with high viral replication activity. Additionally, the combined detection of dsRNA intermediates and viral antigens may help to bridge the interpretation gaps between viral antigen levels and viral titers at a single time point. Further testing in other viral infections or species is needed to assess the potential of dsRNA as an early marker for viral infections. [ABSTRACT FROM AUTHOR]

Owing to their continuous evolution, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) display disparate pathogenicity in mouse models. Omicron and its sublineages have been dominant worldwide. Compared to pre-Omicron VOCs, early Omicron subvariants reportedly cause attenuated disease in human ACE-2-expressing mice (K18-hACE-2). In late 2022, the frequency of Omicron subvariant XBB.1.5 rapidly increased and it progressively replaced other circulating strains. The emergence of new strains requires current SARS-CoV-2 clinical animal model re-evaluation. In this study, we aim to characterize XBB.1.5 pathogenesis in K18-hACE-2. Herein, we demonstrated that XBB.1.5 infection is associated with significant weight loss, severe lung pathology, and substantial mortality. Intranasal XBB.1.5 infection resulted in 100% mortality in K18-hACE2 mice. High virus titers were detected in the lungs on days 3 and 5 after infection. Moreover, XBB.1.5 productively infected the cells within the nasal turbinate, olfactory bulb, intestines, and kidneys. In addition, in a subset of infected mice, we detected high virus titers in the brain. Consistently, we detected high viral antigen expression in the lungs. Furthermore, we observed severe lung injury hallmarks (e.g., immune cell infiltration, perivascular cuffing, and alveolar consolidation). Using immunofluorescence labeling and cytometric analysis, we revealed that XBB.1.5 infection leads to CD45+ cell influx into the lung parenchyma. We further demonstrated that most immune infiltrates are CD11b+ CD11c+ dendritic cells. Additionally, we detected significant induction of proinflammatory cytokines and chemokines in infected lungs. Taken together, our data show that Omicron subvariant XBB.1.5 is highly pathogenic in K18-hACE2 mice. [ABSTRACT FROM AUTHOR]

Bovine coronavirus (BCoV), a persistent threat to global cattle industry, has caused significant economic losses worldwide. In this study, a viral strain was isolated from the intestinal content of a diseased calve, and identified by cytopathic effects observation, indirect immunofluorescence assay and electron microscopy. Results showed that BCoV NXWZ2310 belonging to the GIIb genotype and has a three-amino-acid deletion in the serine-rich region of the N gene. Importantly, the BCoV NXWZ2310 strain exhibited strong pathogenicity, causing nasal discharge and watery diarrhea in calves for 8 and 10 days, respectively. Viral shedding was detected in nasal, throat and rectal swabs at levels reaching 106.228 copies/mL, 105.0 copies /mL and 106.692 copies/mL, respectively. Pathological examination showed that NXWZ2310 resulted in parenchymal lesions of the pulmonary lobe and significant intestinal lesions. Both the lungs and intestines displayed marked microscopic lesions with clear viral antigens present. BCoV NXWZ2310 strain with N-gene deletion mutations, caused severe respiratory and digestive disease in calves. Therefore, effective strategies are needed for the prevention and control of this isolate. [ABSTRACT FROM AUTHOR]

Objective: Hepatitis B virus (HBV) infection is associated with the incidence and prognosis of diffuse large B-cell lymphoma (DLBCL), and previous studies differ in terms of clinical characteristics and prognostic factors. In this study, we explored the clinical features and prognostic characteristics of real-world DLBCL patients infected with HBV. Methods: Patients with pathologically diagnosed primary DLBCL at West China Hospital of Sichuan University were enrolled. Patients with follicular lymphoma-transformed DLBCL, primary central nervous system DLBCL, and hepatitis C virus, hepatitis E virus, human immunodeficiency virus, or syphilis infections were excluded. Ultimately, a total of 941 patients were included in this study. All patients included in the study underwent HBV serum marker testing before treatment. The demographic features, clinical characteristics and treatments of patients with different HBV infection states were collected and analyzed comprehensively to identify prognostic factors for OS and PFS. Results: Statistical analysis of the data revealed that hepatitis B surface antigen positive (HBsAg +) DLBCL patients were younger and more likely to present with advanced disease, germinal center B cell-like subtype, B symptoms and splenic involvement. There were no significant differences in OS or PFS among patients with different HBV infection statuses (χ 2 = 0.139, P = 0.933; χ2 = 0.787, P = 0.675); R-CHOP/R-CHOP-like regimens improved prognosis in HBsAg + DLBCL patients (OS: χ2 = 7.679, P = 0.006; PFS: χ2 = 9.042, P = 0.003); antiviral prophylaxis for HBsAg + DLBCL patients improved OS and PFS (HR: 0.336, P = 0.012, 95% CI [0.143, 0.788]; HR: 0.397, P = 0.032, 95% CI [0.171, 0.925]), with tenofovir treatment being particularly effective (χ2 = 4.644, P = 0.031; χ2 = 4.554, P = 0.033). Conclusions: HBsAg + DLBCL patients have unique clinical characteristics, and the use of CD20 monoclonal antibody based regimens significantly improves the outcome and prognosis of patients with HBsAg + DLBCL. Anti-HBV therapy, especially tenofovir, improves the prognosis of DLBCL patients with HBV presenting infection. Timely and sustained antiviral prophylaxis should be the standard strategy for treating DLBCL patients with HBV infection to optimize the efficacy of chemotherapy and immunotherapy. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease (FMD) is a great havoc in agri-business-based countries like Bangladesh, for which existing detection system limits the identification and differentiation of serotypes. In this study, an engineered platform was introduced incorporating serotype-specific FMDV VP1 (structural), serotype-independent VP2 (structural) and 3AB (non-structural) proteins for holistic detection. VP1 sequences were engineered combining sequences of BAN/TA/Dh-301/2016 (serotype O), BAN/CH/Sa-304/2016 (serotype A) and BAN/DH/Sa-318/2016 (serotype Asia1). Consensus 3AB sequence was constructed from the selected prevalent viral genomes. Both VP1 and 3AB along with designed VP2 sequences were optimized for codon usage bias, stable mRNA, secondary and tertiary protein structure. Proteins were synthesized in pET-21a (+) plasmid vector followed by transformation of Escherichia coli BL21(DE3) and IPTG-induced- expression. The western blot analysis of engineered proteins showed that purified VP1 prominently bound to anti-VP1 antibodies in vaccinated sera, whereas 3AB and VP2 bound anti-3AB and anti-VP2 antibodies, respectively from infected cattle sera, all previously collected during epidemiological investigation. Furthermore, dot blot hybridization confirmed efficient antibody capture ability of the membrane-immobilized proteins. This holistic diagnostic platform justifies a comprehensive prototype diagnostic kit that would be cost-effective and efficient for serotype specific and non-specific FMDV sero-surveillance. [ABSTRACT FROM AUTHOR]

Background Reliable biomarkers of coronavirus disease 2019 (COVID-19) outcomes are critically needed. We evaluated associations of spike antibody (Ab) and plasma nucleocapsid antigen (N Ag) with clinical outcomes in nonhospitalized persons with mild-to-moderate COVID-19. Methods Participants were nonhospitalized adults with mild-to-moderate COVID-19 enrolled in ACTIV-2 between January and July 2021 and randomized to placebo. We used quantitative assays for severe acute respiratory syndrome coronavirus 2 spike Ab and N Ag in blood and determined numbers of hospitalization/death events within 28 days and time to symptom improvement. Results Of 209 participants, 77 (37%) had quantifiable spike Ab and 139 (67%) quantifiable N Ag. Median age was 50 years; 111 (53%) were female, 182 (87%) White, and 105 (50%) Hispanic/Latino. Higher risk of hospitalization/death was seen with unquantifiable (22/132 [16.7%]) versus quantifiable (1/77 [1.3%]) spike Ab (risk ratio [RR], 12.83 [95% confidence interval {CI}, 1.76–93.34]) and quantifiable (22/139 [15.8%]) vs unquantifiable (1/70 [1.4%]) N Ag (RR, 11.08 [95% CI, 1.52–80.51]). Increasing risk of hospitalizations/deaths was seen with increasing N Ag levels. Time to symptom improvement was longer with unquantifiable versus quantifiable spike Ab (median, 14 [interquartile range {IQR}, 8 to >27] vs 8 [IQR, 4–22] days; adjusted hazard ratio [aHR], 0.66 [95% CI,.45–.96]) and with quantifiable versus unquantifiable N Ag (median, 12 [7 to >27] vs 10 [5–22] days; aHR, 0.79 [95% CI,.52–1.21]). Conclusions Absence of spike Ab and presence of plasma N Ag predicted hospitalization/death and delayed symptom improvement in COVID-19 outpatients. Clinical Trials Registration NCT04518410 [ABSTRACT FROM AUTHOR]

Japanese encephalitis virus (JEV) is the leading cause of human encephalitis in Asia. JEV is a vector-borne disease, mainly transmitted by Culex mosquitoes, with Ardeidae birds as maintenance hosts and pigs as amplifying hosts. Other vertebrate animal hosts have been suggested to play a role in the epidemiology of JEV. This scoping review followed PRISMA guidelines to identify species in which evidence of naturally occurring JEV infection was detected in vertebrates other than ardeid birds, pigs and people. Following systematic searches, 4372 records were screened, and data were extracted from 62 eligible studies. Direct evidence (virus, viral antigen or viral RNA) of JEV infection was identified in a variety of mammals and birds (not always identified to the species level), including bats, passerine birds (family Turdidae), livestock (cattle [Bos taurus] and a goat [Capra hircus]), carnivores (two meerkats [Suricata suricatta]), and one horse (Equus caballus). Bat families included Pteropodidae, Vespertilionidae, Rhinolophidae, Miniopteridae, Hipposideridae. Indirect evidence (antibodies) was identified in several mammalian and avian orders, as well as reported in two reptile species. However, a major limitation of the evidence of JEV infection identified in this review was diagnostic test accuracy, particularly for serological testing. Studies generally did not report diagnostic sensitivity or specificity which is critical given the potential for cross-reactivity in orthoflavivirus detection. We hypothesise that bats and passerine birds could play an underappreciated role in JEV epidemiology; however, development of diagnostic tests to differentiate JEV from other orthoflaviviruses will be essential for effective surveillance in these, as well as the companion and livestock species that could be used to evaluate JEV control measures in currently endemic regions. Author summary: Japanese encephalitis virus (JEV) is the leading cause of encephalitis in Asia and the Western Pacific, with estimated 100,000 cases in people (mainly children) annually. Up to one third of cases result in death, and of those who survive, half can suffer ongoing neurological problems. Japanese encephalitis virus circulation is complex. It is transmitted via mosquitoes between hosts. Although well-known key hosts include pigs and water birds, our review showed that there are others that should be considered in surveillance programs such as bats and perching birds. We also found that detection is challenging because diagnostic tests cross-react with other viruses. Both improved understanding of hosts and better diagnostic tests are needed to develop surveillance systems to reduce JEV incidence in people. [ABSTRACT FROM AUTHOR]

Background: Viral hepatitis reactivation occurs during various chemotherapy treatments. Patients with high serum titer levels of Hepatitis B virus (HBV) DNA before chemotherapy and those receiving intensive chemotherapy for hematological malignancies are particularly at risk. Aims and Objectives: This study aimed to determine the incidence, predictors, and clinical significance of HBV and hepatitis C virus reactivations during chemotherapy. Materials and Methods: This prospective observational study was conducted at a tertiary care center. Hepatitis B and C virus status was identified before the initiation of cancer treatment. Liver function was monitored in all patients before each cycle of chemotherapy. Patients with deranged liver function were subjected to repeated viral antigen tests and DNA/RNA titer levels. Results: A total of 110 patients were identified as having hepatitis virus reactivation out of 1190 patients. The sites of malignancy were breast, 39.1% (43 patients); colorectal, 11.8% (13 patients); upper gastrointestinal, 10% (11 patients); ovary, 9.1% (10 patients); hematological malignancies, 8.2% (9 patients); lung, 5.6% (6 patients); genitourinary, 4.5% (5 patients); head-and-neck, 4.5% (5 patients); biliary tract, 3.6% (4 patients); brain tumor, 1.8% (2 patients); and others, 1.8% (2 patients). Most of the patients with reactivation received 5-FU/Capecitabine-based chemotherapy 37.3%, (41 patients), taxane plus platinum (10.9%, 12 patients), taxane only (10%, 11 patients), trastuzumab (8.2%, 9 patients), platinum-based (6.4%, 7 patients), tyrosine kinase inhibitors (6.4%, 7 patients), monoclonal antibodies (MABs) (3.6%, 4 patients), anthracyclines (2.7%, 3 patients), immunomodulators (2.7%, 3 patients), and other agents (11.8%, 13 patients). Conclusion: We recommend that Hepatitis B and C virus Screening must me performed before chemotherapy and that non-reactive patients should be vaccinated. [ABSTRACT FROM AUTHOR]

Peptide p176-190, derived from the SARS-CoV-2 spike protein, is one of the major T cell epitopes that elicits the HLA-DR-restricted IL-8 response of human CD4+ T cells. Using PBMCs from a healthy individual primed with an S-protein-based SARS-CoV-2 vaccine, we established a CD4+ T cell line (TM45) and cloned T cells (TM45.2) specific for the peptide. We showed that (i) co-incubation with kynurenine leads to increased IL-8; (ii) T cells incubated in the absence of kynurenine recovered the original levels of cytokine production; and (iii) peptide p176-190 substituted at 176 Leucine for neutral hydrophilic serine completely abolished the cytokine responses of TM45.2 cells, thereby suggesting that 176 L is the first anchor residue for binding to HLA-DR. These observations collectively indicate that (i) enhanced IL-8 responses can be induced by kynurenine, which is produced under infectious conditions in COVID-19; (ii) the response is not a permanent change in the T cell phenotype; and (iii) IL-8 responses associated with harmful neutrophil extracellular traps can be abrogated by a single amino acid substitution of the viral antigens. These findings may shed light on a novel strategy for designing vaccines for viral infections that are accompanied by increased kynurenine production. [ABSTRACT FROM AUTHOR]

African Swine Fever Virus (ASFV), resulting in strain-dependent vascular pathology, leading to hemorrhagic fever, is an important pathogen in swine. The pathogenesis of ASFV is determined by the array and spatial distribution of susceptible cells within the host. In this study, the replication characteristics of ASFV genotype I E70 (G1-E70) and ASFV genotype II Belgium 2018/1 (G2-B18) in the environment of small veins were investigated in an established vein explant model. Immunofluorescence staining analysis revealed that perivenous macrophages (CD163+ cells) were widely distributed in the explant, with most of them (approximately 2–10 cells/0.03 mm2) being present close to the vein (within a radius of 0–348 µm). Upon inoculation with G1-E70 and G2-B18, we observed an increase in the quantity of cells testing positive for viral antigens over time. G1-E70 replicated more efficiently than G2-B18 in the vein explants (7.6-fold for the ear explant at 72 hpi). The majority of ASFV+ cells were CD163+, indicating that macrophages are the primary target cells. Additional identification of cells infected with ASFV revealed the presence of vimentin+, CD14+, and VWF+ cells, demonstrating the cellular diversity and complexity associated with ASFV infection. By the use of this new vein explant model, the susceptibility of vascular and perivascular cells to an ASFV infection was identified. With this model, it will be possible now to conduct more functional analyses to get better insights into the pathogenesis of ASFV-induced hemorrhages. [ABSTRACT FROM AUTHOR]

HIV establishes long-term latent infection in memory CD4+ T cells and also establishes sustained long-term productive infection in macrophages, especially in the central nervous system (CNS). To better understand how HIV sustains infection in macrophages, we performed RNAseq analysis after infection of human monocytederived macrophages (MDMs) with the brain-derived HIV-1 strain YU2 and compared this with acute infection of CD4+ T cells. HIV infection in MDM and CD4+ T cells altered many gene transcripts, but with few overlaps between these different cell types. We found interferon pathways upregulated in both MDM and CD4+ T cells, but with different gene signatures. The interferon-stimulated gene RSAD2/Viperin was among the most upregulated genes following HIV infection in MDMs, but not in CD4+ T cells. RSAD2/Viperin was induced early after infection with various HIV strains, was sustained over time, and remained elevated in established MDM infection even if new rounds of infection were blocked by antiretroviral treatment. Immunofluorescence microscopy revealed that RSAD2/Viperin was induced in HIV-infected cells, as well as in some uninfected neighboring cells. Knockdown of RSAD2/Viperin following the establishment of infection in MDMs reduced the production of HIV transcripts and viral p24 antigen. This correlated with the reduction in the number of multinucleated giant cells, and changes in the HIV DNA and chromatin structure, including an increased DNA copy number and loss of nucleosomes and histone modifications at the long terminal repeat (LTR). RNAseq transcriptomic analysis of RSAD2/Viperin knockdown during HIV infection of MDMs revealed the activation of interferon alpha/beta and gamma pathways and the inactivation of Rho GTPase pathways. Taken together, these results suggest that RSAD2/Viperin supports the sustained infection in macrophages, potentially through mechanisms involving the alteration of the LTR chromatin structure and the interferon response. [ABSTRACT FROM AUTHOR]

Epstein-Barr virus (EBV) infection has been advocated as a prerequisite for developing multiple sclerosis (MS) and possibly the propagation of the disease. However, the precise mechanisms for such influences are still unclear. A large-scale study investigating the host genetics of EBV serology and related clinical manifestations, such as infectious mononucleosis (IM), may help us better understand the role of EBV in MS pathogenesis. This study evaluates the host genetic factors that influence serological response against EBV and history of IM and cross-evaluates them with MS risk and genetic susceptibility in the Swedish population. Plasma IgG antibody levels against EBV nuclear antigen-1 [EBNA-1, truncated = amino acids (aa) (325–641), peptide = aa(385–420)] and viral capsid antigen p18 (VCAp18) were measured using bead-based multiplex serology for 8744 MS cases and 7229 population-matched control subjects. The MS risk association for high/low EBV antibody levels and history of IM was compared to relevant clinical measures along with sex, age at sampling, and associated HLA allele variants. Genome-wide and HLA allele association analyses were also performed to identify genetic risk factors for EBV antibody response and IM history. Higher antibody levels against VCAp18 [odds ratio (OR) = 1.74, 95% confidence interval (CI) = 1.60–1.88] and EBNA-1, particularly the peptide (OR = 3.13, 95% CI = 2.93–3.35), were associated with an increased risk for MS. The risk increased with higher anti-EBNA-1 IgG levels up to 12× the reference risk. We also identified several independent HLA haplotypes associated with EBV serology overlapping with known MS risk alleles (e.g. DRB1*15:01). Although there were several candidates, no variants outside the HLA region reached genome-wide significance. Cumulative HLA risk for anti-EBNA-1 IgG levels, particularly the peptide fragment, was strongly associated with MS. In contrast, the genetic risk for high anti-VCAp18 IgG levels was not as strongly associated with MS risk. IM history was not associated with class II HLA genes but negatively associated with A*02:01 , which is protective against MS. Our findings emphasize that the risk association between anti-EBNA-1 IgG levels and MS may be partly due to overlapping HLA associations. Additionally, the increasing MS risk with increasing anti-EBNA-1 levels would be consistent with a pathogenic role of the EBNA-1 immune response, perhaps through molecular mimicry. Given that high anti-EBNA-1 antibodies may reflect a poorly controlled T-cell defence against the virus, our findings would be consistent with DRB1*15:01 being a poor class II antigen in the immune defence against EBV. Last, the difference in genetic control of IM supports the independent roles of EBNA-1 and IM in MS susceptibility. [ABSTRACT FROM AUTHOR]

This study examines the pivotal role of COVID-19 testing in mitigating disease spread, particularly in underserved rural communities facing health care access challenges. The Southern Nevada Health District successfully implemented a vending program in Clark County, offering free COVID-19 antigen test kits. Strategically located based on health equity indices and featuring a user-friendly, multilingual registration process, these machines proved effective in reaching rural populations. The cost-effective model suggests potential adoption for broader public health interventions and services in other regions. (Am J Public Health. 2024;114(S7):S558–S561. https://doi.org/10.2105/AJPH.2024.307718) [ABSTRACT FROM AUTHOR]

Picornaviridae are non-enveloped ssRNA viruses that cause diseases such as poliomyelitis, hand-foot-and-mouth disease (HFMD), hepatitis A, encephalitis, myocarditis, and foot-and-mouth disease (FMD). Virus-like particles (VLPs) vaccines mainly comprise particles formed through the self-assembly of viral capsid proteins (for enveloped viruses, envelope proteins are also an option). They do not contain the viral genome. On the other hand, the nanoparticles vaccine (NPs) is mainly composed of self-assembling biological proteins or nanomaterials, with viral antigens displayed on the surface. The presentation of viral antigens on these particles in a repetitive array can elicit a strong immune response in animals. VLPs and NPs can be powerful platforms for multivalent antigen presentation. This review summarises the development of virus-like particle vaccines (VLPs) and nanoparticle vaccines (NPs) against picornaviruses. By detailing the progress made in the fight against various picornaviruses such as poliovirus (PV), foot-and-mouth disease virus (FMDV), enterovirus (EV), Senecavirus A (SVA), and encephalomyocarditis virus (EMCV), we in turn highlight the significant strides made in vaccine technology. These advancements include diverse construction methods, expression systems, elicited immune responses, and the use of various adjuvants. We see promising prospects for the continued development and optimisation of VLPs and NPs vaccines. Future research should focus on enhancing these vaccines' immunogenicity, stability, and delivery methods. Moreover, expanding our understanding of the interplay between these vaccines and the immune system will be crucial. We hope these insights will inspire and guide fellow researchers in the ongoing quest to combat picornavirus infections more effectively. [ABSTRACT FROM AUTHOR]

Background: The relationship between chronic hepatitis B (CHB) infection and natural killer (NK) cell dysfunction is well-established, but the specific role of HBV viral antigens in driving NK cell impairment in patients with CHB remains unclear. This study investigates the modulatory effects of hepatitis B virus subviral particles (HBVsvp, a representative model for HBsAg) on the phenotypic regulation (activating and inhibitory receptors), cytokine production and cytotoxic potential of peripheral blood mononuclear cell-derived natural killer cells (PBMCs-derived NK cell), which contributes to NK cell dysfunction in CHB infection, potentially serving as an effective HBV immune evasion strategy by the virus. Methods: NK cells were isolated from peripheral blood of patients with CHB (n=5) and healthy individuals (n=5), stimulated with HBVsvp. Subsequent flow cytometric characterization involved assessing changes in activating (NKp46 and NKG2D) and inhibitory (CD94) receptors expression, quantifying TNF-α and IFN-δ cytokine secretion, and evaluating the cytotoxic response against HepG2.2.15 cells with subsequent HBVsvp quantification. Results: In CHB patients, in vitro exposure of PBMCs-derived NK cell with HBVsvp (represent HBsAg model) significantly reduced NK cell-activating receptors expression (P = 0.022), increased expression of CD94 + NK cells (p = 0.029), accompanied with a reduced TNF-α-IFN-γ cytokine levels, and impaired cytotoxic capacity (evidenced by increased cell proliferation and elevated HBVsvp levels in co-cultures with HepG2.2.15 cells in a time-dependent), relative to healthy donors. Conclusion: These findings suggest that HBVsvp may induce dysfunctional NK cell responses characterized by phenotypic imbalance with subsequent reduction in cytokine and cytotoxic levels, indicating HBVsvp immunosuppressive effect that compromises antiviral defense in CHB patients. These data enhance our understanding of NK cell interactions with HBsAg and highlight the potential for targeting CD94 inhibitory receptors to restore NK cell function as an immunotherapeutic approach. Further clinical research is needed to validate these observations and establish their utility as reliable biomarkers. [ABSTRACT FROM AUTHOR]

Background Evaluation of the impact of a hepatitis B virus (HBV) prevention program that incorporates maternal antiviral prophylaxis on mother-to-child transmission (MTCT) is limited using real-world data. Methods We analyzed data on maternal HBV screening, neonatal immunization, and post-vaccination serologic testing (PVST) for hepatitis B surface antigen (HBsAg) among at-risk infants born to HBV carrier mothers from the National Immunization Information System during 2008–2022. Through linkage with the National Health Insurance Database, information on maternal antiviral therapy was obtained. Multivariate logistic regression was performed to explore MTCT risk in relation to infant–mother characteristics and prevention strategies. Results In total, 2 460 218 deliveries with maternal HBV status were screened. Between 2008 and 2022, the annual HBsAg and hepatitis B e antigen (HBeAg) seropositivity rates among native pregnant women decreased from 12.2% to 2.6% and from 2.7% to 0.4%, respectively (P for both trends <.0001). Among the 22 859 at-risk infants who underwent PVST, the MTCT rates differed between infants born to HBsAg-positive/HBeAg-negative and HBeAg-positive mothers (0.75% and 6.33%, respectively; P <.001). MTCT risk increased with maternal HBeAg positivity (odds ratio [OR], 9.29; 95% confidence interval [CI], 6.79–12.73) and decreased with maternal antiviral prophylaxis (OR, 0.28; 95% CI,.16–.49). For infants with maternal HBeAg positivity, MTCT risk was associated with mothers born in the immunization era (OR, 1.40; 95% CI, 1.17–1.67). Conclusions MTCT was related to maternal HBeAg positivity and effectively prevented by maternal prophylaxis in the immunized population. At-risk infants born to maternal vaccinated cohorts might possibly pose further risk. [ABSTRACT FROM AUTHOR]

Simple Summary: Patients with chronic lymphocytic leukemia (CLL) are more susceptible to infections, which are also the most common cause of death in these patients. Previous studies in patients with CLL described elevated levels of FOXP3+ regulatory T cells (Tregs), which also correlated with decreased T cell responses to microbial antigens. As the activation of the STAT5 transcription factor induces the expression of FOXP3 and human CD4+FOXP3+ T cells that also contain nonsuppressive T cells, we analyzed STAT5 phosphorylation (pSTAT5) and suppressive subpopulations, including activated Tregs (aTregs). We found a significantly increased frequency of aTregs in patients with advanced stages, which significantly correlated with the total tumor mass score. aTreg expansion in vitro was associated with significantly higher aTreg pSTAT5 responses to SARS-CoV-2 antigen-specific stimulation in vitro. Finally, a subgroup of patients characterised by an increased aTreg percentage among CD4+FOXP3+ T cells experienced a more severe disease course with serious grade ≥3 infections during follow-up. Introduction: Advanced chronic lymphocytic leukemia (CLL) is accompanied by increased circulating regulatory T cells (Tregs) and increased susceptibility to severe infections, which were also shown to entail a striking induction of FOXP3 expression in Tregs. As homeostasis of the most suppressive CD45RA−FOXP3high activated Treg (aTreg) subset differs, it is critical to analyse homeostatic signalling in Treg subsets. Materials and Methods: In this study, by using conventional and imaging flow cytometry, we monitored STAT5 signalling/phosphorylation (pSTAT5) and investigated Treg subsets in relation to the Binet stage, the total tumor mass score (TTM) and the disease course during a follow-up of 37 patients with CLL. Results: The aTreg percentage was significantly increased among CD4+ T cells from patients with advanced disease and significantly correlated with the TTM. A subgroup of patients with higher aTreg percentages among CD4+FOXP3+ T cells at the start of therapy was characterised by more frequent episodes of severe infections during follow-up. Conclusions: The results suggesting that an aTreg fraction could represent a possible marker of a severe disease course with infectious complications. Augmented homeostatic STAT5 signalling could support aTreg expansion, as higher pSTAT5 levels were significantly correlated with an increased aTreg frequency among CD4+FOXP3+ T cells during the follow-up of patients on therapy, as well as following SARS-CoV-2 antigen-specific stimulation in vitro. [ABSTRACT FROM AUTHOR]

There is a need to investigate novel strategies in order to create an effective, broadly protective vaccine for current and future severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks. The currently available vaccines demonstrate compromised efficacy against emerging SARS-CoV-2 variants of concern (VOCs), short-lived immunity, and susceptibility to immune imprinting due to frequent boosting practices. In this study, we examined the specificity of cross-reactive IgG antibody responses in mRNA-vaccinated, AstraZeneca-vaccinated, and unvaccinated donors to identify potentially conserved, cross-reactive epitopes to target in order to create a broadly protective SARS-CoV-2 vaccine. Our study provides evidence for cross-reactive IgG antibodies specific to eight different spike (S) variants. Furthermore, the specificities of these cross-variant IgG antibody titers were associated to some extent with spike S1- and S2-subunit-derived epitopes P1 and P2, respectively. In addition, nucleocapsid (N)- and membrane (M)-specific IgG antibody titers correlated with N- and M-derived epitopes conserved across beta-CoVs, P3–7. This study reveals conserved epitopes of viral antigens, targeted by natural and/or vaccine-induced human immunity, for future designs of next-generation COVID-19 vaccines. [ABSTRACT FROM AUTHOR]

Background Although antivirals remain important for the treatment COVID-19, methods to assess treatment efficacy are lacking. Here, we investigated the impact of remdesivir on viral dynamics and their contribution to understanding antiviral efficacy in the multicenter Adaptive COVID-19 Treatment Trial 1, which randomized patients to remdesivir or placebo. Methods Longitudinal specimens collected during hospitalization from a substudy of 642 patients with COVID-19 were measured for viral RNA (upper respiratory tract and plasma), viral nucleocapsid antigen (serum), and host immunologic markers. Associations with clinical outcomes and response to therapy were assessed. Results Higher baseline plasma viral loads were associated with poorer clinical outcomes, and decreases in viral RNA and antigen in blood but not the upper respiratory tract correlated with enhanced benefit from remdesivir. The treatment effect of remdesivir was most pronounced in patients with elevated baseline nucleocapsid antigen levels: the recovery rate ratio was 1.95 (95% CI, 1.40–2.71) for levels >245 pg/mL vs 1.04 (95% CI,.76–1.42) for levels <245 pg/mL. Remdesivir also accelerated the rate of viral RNA and antigen clearance in blood, and patients whose blood levels decreased were more likely to recover and survive. Conclusions Reductions in SARS-CoV-2 RNA and antigen levels in blood correlated with clinical benefit from antiviral therapy. Clinical Trial Registration NCT04280705 (ClinicalTrials.gov). [ABSTRACT FROM AUTHOR]

Information on the abundance and diversity of phytopathogenic viruses in Ukraine is very variable and limited. There is a high importance of a complex study of the species composition and ways of spreading crop viruses, as well as the development of epiphytotic forecasting systems, which will help to limit the ranges of these viruses and save crop yields. Consequently, the aim of our study was to explore the species composition and frequency of mono-and mixed virus infection of vegetable crops in Ukrainian agrocenoses and to identify the possible etiology of its occurrence. Methods. The samples were analyzed for the presence of viral antigens by enzyme-linked immunosorbent assay in sandwich and indirect modifications. For the detection of viral antigens in ELISA, test systems manufactured by Loewe were used. To identify the virus, the material was homogenized and purified, and then registered on a reader. Results. The frequency of vegetable crops damaged by diseases of viral etiology increased by 25-27% compared to the previous years of the study. Serological analysis showed that 59% of the studied samples of the Cucurbitaceae family and 54% of the Solanaceae family were affected by the main viral diseases most common in Ukraine. The seed way of transmission of vegetable viruses in Ukraine was demonstrated as one of the sources of viruses in agrocenoses. The presence of antigens to cucumber mosaic virus (CMV) in 14.3% of the studied seeds, zucchini yellow mosaic virus (ZYMV) - 11.2%, and tomato mosaic virus (ToMV) - 12.6% was shown. This allows us to suggest that sowing those seeds in the future will contribute to the spread of these viruses across Ukraine. Analysis of soil samples showed the presence of antigens of cucumber mosaic virus, tobacco mosaic virus, and potato virus X. The lowest level of antigens to CMV was detected in the soils of Vinnytsia region, to PVX - in the Kyiv and Cherkasy regions, and to TMV - in the Odesa region. Conclusions. Vegetable agrocenoses in Ukraine are more often affected by viruses belonging to the Tobamovirus, Cucumovirus, Potyvirus, and Tospovirus genera of the Bromoviridae, Potyviridae, and Bunyaviridae families. In addition to the increasing areas of viral monoinfection, there is an active spread of mixed infection, or «superinfection», in Ukrainian agrocenosis. Mixed infections are mainly formed during the growth and development of the tested vegetable crops. All of this leads to further signifi cant spread of not only mono-but also mixed virus infection of vegetable crops. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to examine the serological and infectious characteristics of the Xokós indigenous community in Brazil, both prior to and following COVID-19 immunization; Methods: Immunofluorescence assays were employed to identify the SARS-CoV-2 viral antigen, while IgM and IgG antibody tests for COVID-19 were utilized to assess the participants' infectious and serological profiles in July 2020, before the commencement of the COVID-19 vaccination campaign, and in March 2022, during the booster dose vaccination campaign; Results: The majority of participants (n = 22) were female, with an average age of 42.20 years. The most prevalent comorbidity was hypertension (60%; n = 9), followed by hypertension associated with diabetes (20%; n = 3). No statistically significant correlation was found between the timing of vaccination and the levels of antigens or IgM. However, the prevalence of reactive antigens and IgM was 13.3% (n = 4) in the pre-vaccination group and 3.3% (n = 1) in the post-vaccination group. A statistically significant difference in IgG production was observed before and after vaccination (χ2(1) = 39.095, p < 0.01), as well as differences in IgG antibody detection before and after vaccination and in the vaccines used. Participants showed a higher probability of reactive IgG antibodies following vaccination; Conclusions: Our data demonstrate the beneficial effects of vaccination on the indigenous community, highlighting that continued immunization is a crucial step in protecting indigenous health and preventing severe outbreaks and deaths associated with the disease. [ABSTRACT FROM AUTHOR]

Primary Effusion Lymphoma (PEL) cells carry Kaposi's sarcoma-associated herpesvirus (KSHV) in a latent state, except for a small number of cells in which the virus replicates to ensure its persistence into the infected host. However, the lytic cycle can be reactivated in vitro by exposing these lymphoma cells to various treatments, leading to cell lysis. To restrict viral antigen expression, KSHV induces repressive epigenetic changes, including DNA methylation and histone modifications. Among the latter, histone deacetylation and tri-methylation of Histone H3 lisyne-27 (H3K27me3) have been reported to play a role. Here, we found that the inhibition of H3K27 tri-methylation by valemetostat DS3201 (DS), a small molecule that inhibits Enhancer of Zeste Homolog 2 (EZH2) methyltransferase, induced the KSHV lytic cycle in PEL cells, and that this effect involved the activation of the wtp53–p21 axis and autophagic dysregulation. DS also potentiated the lytic cycle activation mediated by the Histone deacetylases (HDAC) inhibitor Suberoylanilide hydroxamic acid (SAHA) and reinforced its cytotoxic effect, suggesting that such a combination could be used to unbalance the latent/lytic cycle and further impair the survival of PEL cells. [ABSTRACT FROM AUTHOR]

The emergence of novel pathogens, exemplified recently by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), highlights the need for rapidly deployable and adaptable diagnostic assays to assess their impact on human health and guide public health responses in future pandemics. In this study, we developed an automated multiplex microscopy assay coupled with machine learning-based analysis for antibody detection. To achieve multiplexing and simultaneous detection of multiple viral antigens, we devised a barcoding strategy utilizing a panel of HeLa-based cell lines. Each cell line expressed a distinct viral antigen, along with a fluorescent protein exhibiting a unique subcellular localization pattern for cell classification. Our robust, cell segmentation and classification algorithm, combined with automated image acquisition, ensured compatibility with a high-throughput approach. As a proof of concept, we successfully applied this approach for quantitation of immunoreactivity against different variants of SARS-CoV-2 spike and nucleocapsid proteins in sera of patients or vaccinees, as well as for the study of selective reactivity of monoclonal antibodies. Importantly, our system can be rapidly adapted to accommodate other SARS-CoV-2 variants as well as any antigen of a newly emerging pathogen, thereby representing an important resource in the context of pandemic preparedness. [ABSTRACT FROM AUTHOR]

Recent studies have documented prolonged expression of viral antigens and RNA and associated inflammation after infection with SARS-CoV-2 in a substantial proportion of infected patients. The persisting SARS-CoV-2 effects and findings, with inflammation associated with continued detection of viral antigens, especially resemble those previously reported for influenza virus, as well as respiratory syncytial virus (RSV). The reports indicate the need for improved insight into the mechanisms whereby post-SARS-CoV-2 infection-related illness is apparently more common and perhaps even more persistent after infection than observed for other respiratory viruses. [ABSTRACT FROM AUTHOR]

Given the myriad of available tests, guidelines and treatments, chronic infection with the hepatitis B virus (HBV) can seem daunting for the nonspecialist. However, its prevalence among some of the most vulnerable in society, the stigma surrounding it and its potential to lead to cirrhosis and hepatocellular carcinoma (HCC) make it crucial for the frontline primary care physician to understand. [ABSTRACT FROM AUTHOR]

Rabbit hemorrhagic disease virus 2 (RHDV2) has spread across the United States infecting and causing death in domestic and wild rabbits. Immunohistochemistry (IHC) would be a useful tool for the detection of RHDV2 antigen in tissues as it is inexpensive and readily achievable in most diagnostic laboratories. However, there is no readily available antibody for this purpose. To fill this void, we generated an RHDV2 capsid protein VP60–specific antibody in chicken eggs and validated the antibody using formalin-fixed tissues from 5 domestic rabbits naturally infected with RHDV2. Viral antigen was detected immunohistochemically in various tissues, most prominently in hepatocytes and macrophages in liver, and in macrophages in spleen and cecal lymphoid tissue. Intravascular mononuclear cells in lung and renal tubular and biliary epithelium also were immunolabeled. Both nuclear and cytoplasmic immunolabeling were observed. This peptide-generated antibody is a potentially useful tool as an adjunct to reverse-transcription PCR or in situ hybridization for detection of RHDV2 in tissues. [ABSTRACT FROM AUTHOR]

The preS1 region of the large hepatitis B virus (HBV) surface protein is a crucial component in HBV infection; however, its impact on the development of hepatocellular carcinoma (HCC) remains unknown. This study investigated the relationship between serum preS1 levels and hepatocarcinogenesis in patients with chronic hepatitis B (CHB). The preS1 levels were measured in 531 patients with CHB without a history of HCC. Among the patients, 293 HBV carriers who had never received nucleotide/nucleoside analog (NA) therapy had their preS1 levels measured at their first visit (non-NA group), and 238 patients who had received NA therapy had their preS1 levels measured at the start of NA administration (NA group). The two groups had no significant differences in hepatitis B surface antigen (HBsAg) levels; however, the NA group's preS1/HBsAg ratio was significantly higher. The preS1/HBsAg ratio was significantly different between patients with CHB not meeting the NA treatment criteria and patients with chronic hepatitis and cirrhosis who were eligible for NA treatment. The predictors of HCC development were analyzed, and the preS1/HBsAg ratio was identified in both groups. The preS1/HBsAg ratio could predict hepatocarcinogenesis in patients with CHB with or without NA administration. [ABSTRACT FROM AUTHOR]

Background: Epstein–Barr virus (EBV) IgA serology for viral capsid antigen (VCA) and early antigen (EA) aids early detection of nasopharyngeal cancer (NPC), resulting in improved survival. We evaluated the diagnostic performance of a prefabricated immunofluorescent assay (IFA) for NPC screening in high‐risk individuals. Methods: Sera from 96 biopsy‐proven patients with NPC diagnosed at the outpatient clinic and 96 healthy family members were tested for EBV‐VCA IgA and EBV‐EA IgA using the prefabricated IFA from EUROIMMUN (EI) and the traditional immunofluorescence method. Results: The AUC of EI EBV‐VCA IgA and EBV‐EA IgA was 0.907 (95% confidence interval [CI]: 0.894–0.965) and 0.898 (95% CI: 0.848–0.947), respectively. Combined testing with the prefabricated assay at a threshold of VCA ≥1:320 or EA ≥1:10 showed 92.7% sensitivity and 81.2% specificity. Overall, the traditional EBV‐EA IgA assay demonstrated the best accuracy (sensitivity 91.7% and specificity 96.9%) at a threshold of ≥1:5. Conclusion: While the traditional IFA method was more accurate, the prefabricated IFA test kit can be a useful tool for NPC screening in high‐risk populations. [ABSTRACT FROM AUTHOR]

Activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) is an immediate early gene that plays a vital role in learning and memory. Arc protein has structural and functional properties similar to viral Group-specific antigen (Gag) protein and mediates the intercellular RNA transfer through virus-like capsids. However, the regulators and secretion pathway through which Arc capsids maneuver cargos are unclear. Here, we identified that phosphatidylinositol-3-phosphate (PI3P) mediates Arc capsid assembly and secretion through the endosomal-multivesicular body (MVB) pathway. Indeed, reconstituted Arc protein preferably binds to PI3P. In HEK293T cells, Arc forms puncta that colocalize with FYVE, an endosomal PI3P marker, as well as Rab5 and CD63, early endosomal and MVB markers, respectively. Superresolution imaging resolves Arc accumulates within the intraluminal vesicles of MVB. CRISPR double knockout of RalA and RalB, crucial GTPases for MVB biogenesis and exocytosis, severely reduces the Arc-mediated RNA transfer efficiency. RalA/B double knockdown in cultured rat cortical neurons increases the percentage of mature dendritic spines. Intake of extracellular vesicles purified from Arc-expressing wild-type, but not RalA/B double knockdown, cells in mouse cortical neurons reduces their surface GlutA1 levels. These results suggest that unlike the HIV Gag, whose membrane targeting requires interaction with plasma-membrane-specific phosphatidyl inositol (4,5) bisphosphate (PI(4,5)P2), the assembly of Arc capsids is mediated by PI3P at endocytic membranes. Understanding Arc's secretion pathway helps gain insights into its role in intercellular cargo transfer and highlights the commonality and distinction of trafficking mechanisms between structurally resembled capsid proteins. [ABSTRACT FROM AUTHOR]

Post-COVID-19 condition is recognized as a multifactorial disorder, with persistent presence of viral antigens, discordant immunity, delayed viral clearance, and chronic inflammation. Obesity has emerged as an independent risk factor for both SARS-CoV-2 infection and its subsequent sequelae. In this study, we aimed to predict the molecular mechanisms linking obesity and post-COVID-19 distress. Viral antigen-exposed adipose tissues display remarkable levels of viral receptors, facilitating viral entry, deposition, and chronic release of inflammatory mediators and cells in patients. Subsequently, obesity-associated inflammatory insults are predicted to disturb cellular and humoral immunity by triggering abnormal cell differentiation and lymphocyte exhaustion. In particular, the decline in SARS-CoV-2 antibody titers and T-cell exhaustion due to chronic inflammation may account for delayed virus clearance and persistent activation of inflammatory responses. Taken together, obesity-associated defective immunity is a critical control point of intervention against post-COVID-19 progression, particularly in subjects with chronic metabolic distress. [ABSTRACT FROM AUTHOR]

Foot and mouth disease (FMD) is a highly contagious infection caused by FMDvirus (FMDV) that affects livestock worldwide with significant economic impact. The main strategy for the control is vaccination with FMDV chemically inactivated with binary ethylenimine (FMDVi). In FMDV infection and vaccination, B cell response plays a major role by providing neutralizing/protective antibodies in animal models and natural hosts. Extracellular vesicles (EVs) and small EVs (sEVs) such as exosomes are important in cellular communication. EVs secreted by antigen-presenting cells (APC) like dendritic cells (DCs) participate in the activation of B and T cells through the presentation of native antigen membrane-associated to B cells or by transferring MHC-peptide complexes to T cells and even complete antigens from DCs. In this study, we demonstrate for the first time that APC activated with the FMDVi O1 Campos vaccine-antigens secrete EVs expressing viral proteins/peptides that could stimulate FMDV-specific immune response. The secretion of EVs-FMDVi is a time-dependent process and can only be isolated within the first 24 h post-activation. These vesicles express classical EVs markers (CD9, CD81, and CD63), along with immunoregulatory molecules (MHC-II and CD86). With an average size of 155 nm, they belong to the category of EVs. Studies conducted in vitro have demonstrated that EVs-FMDVi express antigens that can stimulate a specific B cell response against FMDV, including both marginal zone B cells (MZB) and follicular B cells (FoB). These vesicles can also indirectly or directly affect T cells, indicating that they express both B and T epitopes. Additionally, lymphocyte expansion induced by EVs-FMDVi is greater in splenocytes that have previously encountered viral antigens in vivo. The present study sheds light on the role of EVs derived fromAPC in regulating the adaptive immunity against FMDV. This novel insight contributes to our current understanding of the immune mechanisms triggered by APC during the antiviral immune response. Furthermore, these findings may have practical implications for the development of new vaccine platforms, providing a rational basis for the design of more effective vaccines against FMDV and other viral diseases. [ABSTRACT FROM AUTHOR]

Background: Natural infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or vaccination triggers antibody production against key viral antigens. However, there is limited evidence on the levels of antibodies produced in naturally infected individuals compared to those vaccinated in Ethiopia. Therefore, we aimed to detect and compare SARS-CoV-2 antibodies produced by naturally infected and vaccinated individuals. Materials and methods: We conducted a multicenter cross-sectional study among a total of 355 naturally infected and 355 vaccinated individuals from November 2022 to April 2023 at 10 selected health facilities in Addis Ababa, Ethiopia. We enrolled the participants consecutively upon their arrival at health facilities until the required sample size was achieved. We used a structured questionnaire to collect data on the demographic and clinical characteristics of the participants. We also collected 3–5 ml of blood samples from all participants and tested for anti-Spike (anti-S) and anti-nucleocapsid (anti-N) antibodies using Cobas 6000. We utilized frequency, mean, or median to describe the data, the Mann-Whitney U test to compare groups, and a generalized linear regression model to assess factors associated with anti-S antibody concentration. We analyzed the data with SPSS version 26, and the level of significance was set at P-value < 0.05. Results: Of the naturally infected participants, 352 (99.5%) had anti-S antibodies and all (100%) had anti-N antibodies, whereas among vaccinated participants, all (100%) had anti-S antibodies, while 323 (91.6%) had anti-N antibodies. Anti-S antibodies produced by vaccinated individuals were significantly (P < 0.001) higher than those produced as a result of natural infection. Being young (P = 0.004), having hypertension (P < 0.001), and having diabetes (P < 0.001) were significantly associated with lower anti-S antibody levels, while being recently vaccinated and having a higher number of vaccine doses were significantly associated with higher anti-S antibody concentrations in vaccinated participants. Having diabetes (P < 0.001) were significantly associated with lower anti-S concentrations in participants who were naturally infected. Conclusion: There is a high seropositivity rate in both naturally infected and vaccinated individuals. However, vaccinated individuals had higher levels of SARS-CoV-2 antibodies than those who were naturally infected, which highlights the significant contribution of vaccination in increasing the protection of COVID-19 in Ethiopia. [ABSTRACT FROM AUTHOR]

Transmissible gastroenteritis virus (TGEV) is an etiological agent of enteric disease that results in high mortality rates in piglets. The economic impact of the virus is considerable, causing significant losses to the pig industry. The development of an efficacious subunit vaccine to provide promising protection against TGEV is of the utmost importance. The viral antigen, spike glycoprotein (S), is widely regarded as one of the most effective antigenic components for vaccine research. In this study, we employed immunoinformatics and molecular dynamics approaches to develop an 'ideal' multi-epitope vaccine. Firstly, the dominant, non-toxic, highly antigenic T (Th, CTL) and B cell epitopes predicted from the TGEV S protein were artificially engineered in tandem to design candidate subunit vaccines. Molecular docking and dynamic simulation results demonstrate that it exhibits robust interactions with toll-like receptor 4 (TLR4). Of particular significance was the finding that the vaccine was capable of triggering an immune response in mammals, as evidenced by the immune simulation results. The humoral aspect is typified by elevated levels of IgG and IgM, whereas the cellular immune aspect is capable of eliciting the robust production of interleukins and cytokines (IFN-γ and IL-2). Furthermore, the adoption of E. coli expression systems for the preparation of vaccines will also result in cost savings. This study offers logical guidelines for the development of a secure and efficacious subunit vaccine against TGEV, in addition to providing a novel theoretical foundation and strategy to prevent associated CoV infections. [ABSTRACT FROM AUTHOR]

The hemagglutination inhibition (HI) assay is a traditional laboratory procedure for detection and quantitation of serum antibodies of hemagglutinating viruses containing the hemagglutinin (HA) gene. The current study aimed to investigate the novel use of virus like particles (VLP) as an antigen for the HI assay. VLPs were prepared from a strain of H5N1 using a baculovirus expression system. The VLPs were characterized using the hemagglutination test, Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting, and transmission electron microscopy. The comparative HI assay was performed using three different seed antigens: A/chicken/Mexico/232/94 (H5N2), A/chicken/Egypt/18-H/09(H5N1) and A/goose/Guangdong/1/1996(H5N1). The HI assay of serum antibody titrations using homologous antigens to these vaccinal seeds were compared to the VLP's antigens for the same serum. The HI titers were logically relevant to the similarity between VLP antigens and vaccinal seeds, indicating the VLPs behave similarly to the standard HI assay which uses inactivated whole virus as an antigen. VLPs could be considered as an alternative to the HI assay antigen as they show a relatedness between the similarity with vaccinal seed and serum antibodies. Compared to typical entire H5N1 viral antigen prepared in SPF eggs that require proper inactivation to avoid any public health risk, VLPs prepared in tissue culture, plants or insect cells are a safe, inexpensive and scalable alternative to inactivated whole virus antigen. [ABSTRACT FROM AUTHOR]

Foot and mouth disease (FMD) is a highly contagious viral disease affecting cloven-hoofed animals. This disease is one of the most important in animal health due to its significant socio-economic impact, especially in case of an outbreak. One important challenge associated with this disease is the ability of the FMD virus (FMDV) to persist in its hosts through still unresolved underlying mechanisms. The absence of relevant in vitro models is one factor preventing advancement in our understanding of FMDV persistence. While a primary bovine cell model has been established using cells from FMDV primary and persistence site in cattle, it appeared interesting to develop a similar model based on ovine anatomical sites of interest to compare host-pathogen interactions. Thus, epithelial cells derived from the palatine tonsils and the dorsal soft palate were isolated and cultured. Their epithelial nature was confirmed using immunofluorescence. Following monolayer infection with FMDV O/FRA/1/2001 Clone 2.2, the FMDV-sensitivity of these cells was evaluated. Dorsal soft palate (DSP) cells were also expanded in multilayers at the air-liquid interface to mimic a stratified epithelium sensitive to FMDV infection. Our investigation revealed the presence of infectious virus, as well as viral antigens and viral RNA, up to 35 days after infection of the cell multilayers. Further experiment with DSP cells from different individuals needs to be reproduced to confirm the robustness of the new model of persistence in multilayer DSP. The establishment of such primary cells creates new opportunities for FMDV research and analysis in sheep cells. [ABSTRACT FROM AUTHOR]

Bats harbor viruses that can cause severe disease and death in humans including filoviruses (e.g., Ebola virus), henipaviruses (e.g., Hendra virus), and coronaviruses (e.g., SARS-CoV). Bats often tolerate these viruses without noticeable adverse immunological effects or succumbing to disease. Previous studies have largely focused on the role of the bat's innate immune response to control viral pathogenesis, but little is known about bat adaptive immunity. A key component of adaptive immunity is the humoral response, comprised of antibodies that can specifically recognize viral antigens with high affinity. The antibody genes within the 1,400 known bat species are highly diverse, and these genetic differences help shape fundamental aspects of the antibody repertoire, including starting diversity and viral antigen recognition. Whether antibodies in bats protect, mediate viral clearance, and prevent transmission within bat populations is poorly defined. Furthermore, it is unclear how neutralizing activity and Fc-mediated effector functions contribute to bat immunity. Although bats have canonical Fc genes (e.g., mu, gamma, alpha, and epsilon), the copy number and sequences of their Fc genes differ from those of humans and mice. The function of bat antibodies targeting viral antigens has been speculated based on sequencing data and polyclonal sera, but functional and biochemical data of monoclonal antibodies are lacking. In this review, we summarize current knowledge of bat humoral immunity, including variation between species, their potential protective role(s) against viral transmission and replication, and address how these antibodies may contribute to population dynamics within bats communities. A deeper understanding of bat adaptive immunity will provide insight into immune control of transmission and replication for emerging viruses with the potential for zoonotic spillover. [ABSTRACT FROM AUTHOR]

Background: Patients with acute-on-chronic liver failure (ACLF) who take entecavir (ETV) and tenofovir disoproxil fumarate (TDF) experience a reduction in hepatic events and mortality. The effectiveness of tenofovir alafenamide (TAF) was not well investigated. This study was aim to compare the antiviral efficacy and mortality between TAF and ETV in patients with ACLF caused by the hepatitis B virus (HBV). Methods: One hundred and six patients with HBV-ACLF who received TAF (25 mg/day) and ETV (0.5 mg/day) for 12 weeks were analyzed. The primary endpoints were overall mortality and liver transplantation (LT) at week 12. Biochemical responses, virologic responses, mortality, drug safety, and side effects were evaluated. Results: At 4 and 12 weeks of TAF treatment, patients showed significantly higher HBV-DNA reduction (P <.001), higher HBV-DNA undetectability rates (P <.001), and lower HBV DNA levels (P <.001) in serum. Lower Child-Turcotte-Pugh (CTP) scores (P =.003) were observed at 4 weeks in the TAF group, although the CTP scores showed no difference between TAF group and ETV group at 12 weeks (P = 1.143). Lower alanine aminotransferase (ALT) levels of patients in the TAF group at week 4 and 12 were observed (P =.023 and P <.0001, separately). The mortality of TAF group was lower after 4 weeks of treatment (P =.038); however, the 2 groups had similar mortality rates at week 8 and 12. Among the causes of death in HBV-ACLF patients, we found the same incidence of liver-related problems in both groups (P >.05). Conclusions: This study showed that ACLF patients with chronic HBV infection treated with TAF had a rapid decline in HBV DNA, a higher rate of ALT reduction and improved CTP scores compared to the ETV group, thereby improving patient survival. [ABSTRACT FROM AUTHOR]

Background: Salivary gland neoplasms (SGNs) pose a challenge to both pathologists and clinicians. Despite research, the etiology of these neoplasms remains unclear. This study aimed to identify any potential association between the presence of hepatitis C virus (HCV) at the protein or gene level and epithelial salivary gland neoplasms. Methods: Formalin-fixed paraffin-embedded (FFPE) blocks of epithelial salivary gland neoplasms were retrieved from the archives of the Oral and Maxillofacial Pathology Department, Faculty of Dentistry, Cairo University within the 5-year period from 2016 to 2020. Immunohistochemistry was used to assess HCV core antigen, while reverse transcription polymerase chain reaction was employed for the evaluation of HCV RNA. Results: A total of 44 specimens were collected, 28 of which were benign neoplasms and 16 were malignant neoplasms. There was a statistically significant difference in HCV positivity between the two groups (P-value = 0.036). Benign tumors showed a statistically significant lower percentage of positive cases than malignant tumors. The localization of staining was also evaluated, revealing various patterns of HCV core antigen expression, including diffuse cytoplasmic, patchy cytoplasmic, nuclear, and a combination of nuclear and cytoplasmic expression. There was no statistically significant difference between the expression patterns in benign and malignant tumors (P-value = 0.616). Given that Pleomorphic Adenoma and Mucoepidermoid Carcinoma were the predominant tumor types in this study, four cases were selected for RNA detection. HCV RNA was detected in all cases using RT-PCR. Conclusions: HCV core antigen is frequently detected in SGNs and is suggested to be a potential risk factor for the development of these neoplasms. Further studies are required to discover other biomarkers, their roles, and the pathways associated with HCV in SGNs. [ABSTRACT FROM AUTHOR]

Background: Pigeon leukosis is primarily caused by avian leukosis virus subgroup A (ALV-A). It infects and transforms lymphoid cells, leading to the development of tumors in various lymphoid tissues and other organs especially the liver. Aim: This study was conducted to diagnose lymphoid leukosis in a naturally infected pigeon flock in Egypt. Methods: Tissue specimens from the liver, spleen, thymus, kidney, lung, proventriculus, gizzard, intestine, pancreas, heart, pectoral muscle, ovary, and testes were collected from infected birds for pathological and immunohistochemical examinations. Results: Clinical signs were generally nonspecific and comprised weakness, dehydration, and emaciation. Gross lesions were mostly in the liver and spleen, in the form of minute white nodules scattered on the liver surface. Microscopic examination of the liver, spleen, and kidneys showed masses of uniform sizes and the presence of differentiated lymphoid cells. These cells appeared as large mononuclear cells with poorly defined cell membranes. Immunohistochemical investigation exhibited that the ALV-A positive indicators were chiefly accessible in the liver, ovary, spleen, and kidney. Conclusion: Lymphoid leukosis in pigeons could be provisionally diagnosed by a pathological picture of characteristic tumors and confirmed by immunoreactivity of viral antigens in different tissues. [ABSTRACT FROM AUTHOR]

Synergistic interactions between human herpesvirus 6A (HHV‐6A) and Epstein–Barr virus (EBV) are hypothesized in the etiopathogenesis of multiple sclerosis (MS). This study investigated if HHV‐6A and EBV seroreactivities interact regarding the risk of developing MS. Antibodies against viral antigens were analyzed in biobank samples from 670 individuals who later developed MS and matched controls. Additive interactions were analyzed. A significant interaction between HHV‐6A and EBNA‐1 seroreactivities was observed in study participants above the median age of 24.9 years (attributable proportion due to interaction = 0.45). This finding supports the hypothesis that HHV‐6A and EBV infections interact in MS development. ANN NEUROL 2024;96:302–305 [ABSTRACT FROM AUTHOR]

Patients with immunodeficiency are at higher risk of severe disease and death following SARSCoV-2 infection compared to the general population. Here, we describe humoral and cellular immune responses in 5 patients with immunodeficiency, 2 patients with multiple sclerosis, 1 patient with chronic lymphocytic leukemia (CLL), 1 patient with Good's syndrome, and 1Human Immunodeficiency Virus (HIV) positive with developed Acquired immunodeficiency syndrome (AIDS)- patient. T-cell responses were evaluated using the QuantiFERON SARS-CoV-2 assay following incubation with the SARS-CoV-2 Ag1, Ag2, and Ag3 viral antigens. Immunophenotyping of CD4+ and CD8+ T cells and CD19+ and CD20+ B cells was determined by flow cytometry. All studied immunocompromised patients or those with acquired immune dysregulation patients showed reduced cellular immune responses (release of interferon (IFN)-γ) to SARS-CoV-2 antigens than healthy controls [patients; Ag1, Ag2 and Ag3 and Nil (Median 5-95% percentile) (12 (1-95), 12 (1.5-78), 13.5 (12-95) and 3 (1-98) U/mL)], controls; Ag1, Ag2 and Ag3 and Nil (Median 5-95% percentile) 24.5 (7-89), 65 (31-173), 53.5 (13-71.5) and 3 (1-14) U/mL)]. The frequency of peripheral blood B cells was also reduced in these patients compared to healthy control subjects. T-cell-dependent antibody responses require the activation of B cells by helper T cells. Reduced B cell numbers in immunocompromised patients infected with SARS-CoV-2 indicate the need for these patients to take additional precautions to prevent COVID-19 infection. [ABSTRACT FROM AUTHOR]

Dengue virus (DENV) infection has emerged as a global health problem, with no specific treatment available presently. Clinacanthus nutans (Burm. f.) Lindau extract has been used in traditional medicine for its anti-inflammatory and antiviral properties. We thus hypothesized C. nutans had a broad-ranged activity to inhibit DENV and the liver inflammation caused by DENV infection. The study showed that treatment using C. nutans extract during DENV infection (co-infection step) showed the highest efficiency in lowering the viral antigen concentration to 22.87 ± 6.49% at 31.25 μg/mL. In addition, the virus–host cell binding assay demonstrated that C. nutans treatment greatly inhibited the virus after its binding to Huh7 cells. Moreover, it could remarkably lower the expression of cytokine and chemokine genes, including TNF-α, CXCL10, IL-6, and IL-8, in addition to inflammatory mediator COX-2 genes. Interestingly, the activation of the NF-κB signaling cascade after C. nutans extract treatment was dramatically decreased, which could be the underlying mechanism of its anti-inflammatory activity. The HPLC profile showed that gallic acid was the bioactive compound of C. nutans extract and might be responsible for the antiviral properties of C. nutans. Taken together, our results revealed the potential of C. nutans extract to inhibit DENV infection and lower inflammation in infected cells. [ABSTRACT FROM AUTHOR]

Copyright of Viral Hepatitis Journal / Viral Hepatit Dergisi is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)