Search Results (263)

T-cell receptors (TCRs) exhibit degeneracy, enabling individual TCRs to recognize multiple altered peptide ligands (APLs) derived from a single cognate antigen. This characteristic has been involved in the pathogenesis of autoimmune diseases through cross-reactivity between microbial and self-antigens. Cytotoxic T lymphocytes (CTLs), which recognize peptide–MHC class I complexes via TCRs, play a critical role in the immune response against viral infections. However, the extent to which TCR degeneracy within a population of virus-specific CTLs contributes to effective viral control remains poorly understood. In this study, we investigated the magnitude and functional relevance of TCR degeneracy in CTLs targeting an immunodominant epitope of human T-cell leukemia virus type 1 (HTLV-1) in patients with HTLV-1-associated myelopathy (HAM). Using peripheral blood mononuclear cells (PBMCs) from these patients, we quantified TCR degeneracy at the population level by comparing CTL responses to a panel of APLs with responses to the cognate epitope. Our findings demonstrated that increased TCR degeneracy, particularly at the primary TCR contact residue at position 5 of the antigen, was inversely correlated with HTLV-1 proviral load (p = 0.038, R = −0.40), despite similar functional avidity across patient-derived CTLs. Viral sequencing further revealed that CTLs with high TCR degeneracy exerted stronger selective pressure on the virus, as indicated by a higher frequency of nonsynonymous substitutions within the epitope-encoding region in patients with highly degenerate TCR repertoires. Moreover, TCR degeneracy was positively correlated with the recognition rate of epitope variants (p = 0.018, R = 0.76), suggesting that CTLs with high TCR degeneracy exhibited enhanced recognition of naturally occurring epitope variants compared to those with low TCR degeneracy. Taken together, these results suggest that virus-specific CTLs with high TCR degeneracy possess superior antiviral capacity, characterized by broadened epitope recognition and more effective suppression of HTLV-1 infection. To our knowledge, this is the first study to systematically quantify TCR degeneracy in HTLV-1-specific CTLs and evaluate its contribution to viral control in HAM patients. These findings establish TCR degeneracy as a critical determinant of antiviral efficacy and provide a novel immunological insight into the mechanisms of viral suppression in chronic HTLV-1 infection. Full article

Background: This study intended to fully assess the predictive efficiency of different clinical laboratory parameters for the mortality risk in severe fever with thrombocytopenia syndrome (SFTS). Methods: We systematically searched the Web of Science, PubMed, Cochrane Library, and Embase up to 13 December 2024 for studies on the association of laboratory parameters with SFTS mortality. Two investigators were independently responsible for the study screening and data extraction, and they assessed the study quality using the Newcastle–Ottawa Scale (NOS). Stata17.0 was adopted for the meta-analyses. Results: We finally included 33 observational studies involving 9502 participants (1799 deaths and 7703 survivors). The results showed that increases in the viral load (odds ratio (OR) 1.93, 95% confidence interval (CI) 1.56–2.38), neutrophil-to-lymphocyte ratio (hazard ratio (HR) 1.31, 95% CI 1.13–1.51), neutrophil percentage (HR 1.02, 95% CI 1.01–1.03), white blood cells (HR 1.06, 95% CI 1.01–1.11), activated partial thromboplastin time (OR 1.07, 95% CI 1.04–1.09), prothrombin time (OR 1.31, 95% CI 1.03–1.65), creatine kinase-myocardial band (OR 1.01, 95% CI 1.01–1.02), and procalcitonin (HR 1.27, 95% CI 1.10–1.47) greatly increased the SFTS mortality, while decreases in the lymphocyte percentage (HR 0.96, 95% CI 0.94–0.98), platelets (HR 0.98, 95% CI 0.97–0.99), and albumin (HR 0.91, 95% CI 0.86–0.96) also greatly increased the SFTS mortality; the results were all statistically significant (p < 0.05). Conclusion: Abnormalities of laboratory parameters (e.g., viral load, blood routine, coagulation, multi-organ dysfunction, and inflammation indicators) are good predictors of SFTS mortality, which can provide valuable references in clinical practice. Full article

Equine Herpesvirus Type 1 (EHV-1) is a significant pathogen within the Alphaherpesvirinae subfamily, causing respiratory disease, abortions, and, in severe cases, equine herpesvirus myeloencephalopathy (EHM). While nasal swabs and blood samples are commonly used for real-time polymerase chain reaction (RT-PCR) diagnosis, variability in viral shedding necessitates exploring additional sample types. This study reports the first molecular detection of EHV-1 in ocular swabs from naturally infected horses during an outbreak in the Valencian Community in 2023. Nasal and ocular swabs were collected from ten symptomatic horses and analyzed via RT-PCR. EHV-1 was detected in all cases, with higher viral loads in nasal samples. Although nasal swabs remain the most reliable sample for EHV-1 detection, the presence of viral DNA in tear fluid suggests a previously unrecognized route of viral shedding. These findings support further investigation into the role of ocular secretions in the pathogenesis and epidemiology of EHV-1. Additional studies are needed to determine the clinical relevance and potential utility of ocular swabs in specific outbreak scenarios. Full article

Background: Dengue is a global health concern, with half of the world’s population at risk and no antiviral treatment available. This Phase 0 study investigated dengue infections among household contacts (HHCs) of dengue index cases (ICs) and assessed the feasibility of conducting a Phase 2 trial for a novel antiviral. Methods: Participants were enrolled in Nha Trang, Vietnam, from April 2022 to February 2023. Dengue ICs were identified within 72 h of fever onset, and their healthy adult HHCs enrolled within 48 h. Blood samples and questionnaires were collected bi-weekly for four weeks, with a follow-up visit on day 40. DENV RT-qPCR, NS1, and anti-DENV IgM/IgG ELISAs were performed. Results: Overall, 130 dengue ICs and 301 HHCs were enrolled, with 91.7% (276/301) completing all follow-up visits. Baseline anti-DENV IgG showed prior dengue infections in 262/301 HHCs (87.0%). Fifty HHCs were excluded from the HHC infection analysis based on evidence of a DENV infection (viral load [VL], NS1, IgM, and IgG results) at enrollment. During follow-up, 2.0% of HHCs (5/251) had DENV infections based on virological parameters (DENV RNA and/or NS1 positivity), and anti-DENV IgG/IgM seroconversion was detected in 7.2% (18/251). Conclusions: This study demonstrated the operational feasibility of a dengue IC-HHC design for a Phase 2 trial. Full article

Background/Objectives: Sustained drug exposure is a key factor in the treatment of patients infected with human immunodeficiency virus (HIV) or hepatitis B virus (HBV) in order to achieve the intended virological response. Although influenced also by other parameters, adherence to the treatment scheme is the most important for adequate drug exposure. This can be assessed by therapeutic drug monitoring (TDM). Tenofovir (TFV) is a nucleotide analogue used in the treatment of both HIV and HBV. Although various analytical methods for the quantification of tenofovir prodrugs have been published, there is limited literature on methods for simultaneous TFV and its active metabolite, tenofovir diphosphate (TFVDP) direct determination. Methods: In this study, we describe a novel micro-liquid-chromatography-mass spectrometry (micro-LC-MS/MS) method for TDM of TFV and TFVDP in biological matrices (whole blood, plasma). The challenging separation of the high-polarity analytes was resolved on an amino stationary phase, eluted in HILIC (hydrophilic interaction liquid chromatography) mode. The sample preparation included a clean-up step with hexane for the removal of lipophilic compounds and then protein precipitation with organic solvent. Results: The achieved low limits of quantification in blood were 0.25 ng/mL for TFV, and 0.5 ng/mL for TFVDP. Linearity, accuracy (91.63–109.18%), precision (2.48–14.08), and stability were validated for whole blood matrix, meeting the guidelines performance criteria. Samples collected from treated patients were analyzed, with results being in accordance with the reported pharmacokinetics. Conclusions: The new method is adequate for analyzing samples in a clinical set-up. The measurement of both TFV and TFVDP improves clinical decision by an in-depth evaluation of long-term adherence, and together with viral load and resistance data helps guiding the treatment towards the intended virological suppression. Full article

Background: Dental professionals were thought to have the most significant risk of coronavirus infection during the pandemic. Since the first Coronavirus Disease 2019 (COVID-19) patient was detected in Japan in January 2020, Japan has faced several waves of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections. However, no cluster of SARS-CoV-2 infections associated with dental procedures has been reported in Japan. In this study, we aimed to investigate the actual status of SARS-CoV-2 infection during the pandemic through antibody testing for dental professionals. We further investigated saliva and oral management-related aerosol to estimate the risk of virus transmission during dental procedures. Methods: SARS-CoV-2 antibody titer in the blood of dental professionals and their families was determined during the pre-vaccinated period of the SARS-CoV-2 wave to see the history of infection in Japan. Viral loads in saliva and in the aerosol generated during the oral management of COVID-19 patients were detected by RT-qPCR. Results: The antibody testing of dental healthcare providers during the early phases of the pandemic in Japan revealed low antibody positivity, which supported the low incidence of infection clusters among dental clinics. The aerosol generated during dental procedures may contain trace levels of SARS-CoV-2, indicating the risk of transmission through dental procedures is limited. Therefore, SARS-CoV-2 did not spread through dental clinics. Conclusions: Very few SARS-CoV-2 infections were observed in dental professionals who took appropriate infection control measures in the early period of the pandemic. Performing dental procedures using standard precautions seems to be sufficient to prevent SARS-CoV-2 infections. Full article

This study investigates the virulence properties and pathogenetic characteristics of the Kazakhstani strain of LSDV (LSDV KZ-Kostanay-2018) in indigenous cattle under controlled conditions. Twelve non-breed cattle were inoculated intradermally and monitored for clinical, pathological, and immunological responses. Clinical signs, including fever, skin nodules, and lymphadenopathy, emerged as early as day 5 post-infection (pi), with peak severity observed between days 11 and 14. Rapid seroconversion was observed, with 100% of animals showing virus-neutralizing antibodies by day 13. Pathological findings revealed extensive necrosis, thrombosis, and edema, with pronounced damage in the spleen, lungs, and lymph nodes. Histological analyses identified widespread destructive changes in the dermis and systemic tissues, consistent with highly aggressive disease progression. Viral genome and replication were confirmed in blood, skin nodules, and lymph nodes, with peak viral loads between days 11 and 14 pi. These results align with findings in Russian cattle infected with the Saratov/2017 strain but demonstrate more rapid symptom onset and severe pathology, suggesting strain-specific virulence. These findings contribute to a deeper understanding of LSDV pathogenesis and underscore the importance of regional adaptations in disease management. Full article

SARS-CoV-2 can cause neurological issues, including cognitive dysfunction in COVID-19 survivors. Endothelial dysfunction, a key mechanism in COVID-19, is also a risk factor for vascular dementia (VaD). Reduced nitric oxide (NO) bioavailability is a pathogenic factor of endothelial dysfunction and platelet aggregation in COVID-19 patients, and endothelial NO synthase (eNOS) levels decline with advancing age, a risk factor for both COVID-19 morbidity and VaD. SARS-CoV-2 also induces cellular senescence and senescence-associated secretory phenotype (SASP). We hypothesized that eNOS deficiency would worsen neuroinflammation, senescence, blood–brain barrier (BBB) permeability, and hypercoagulability in eNOS-deficient mice. Six-month-old eNOS^+/− (pre-cognitively impaired experimental VaD) and wild-type (WT) male mice were infected with mouse-adapted (MA10) SARS-CoV-2. Mice were evaluated for weight loss, viral load, and markers of inflammation and senescence 3 days post-infection. eNOS^+/− mice showed more weight loss (~15%) compared to WT mice (~5%) and increased inflammatory markers (Ccl2, Cxcl9, Cxcl10, IL-1β, and IL-6) and senescence markers (p53 and p21). They also exhibited higher microglial activation (Iba1) and increased plasma coagulation and BBB permeability, despite comparable lung viral loads and absence of virus in the brain. This is the first experimental evidence demonstrating that eNOS deficiency exacerbates SARS-CoV-2-induced morbidity, neuroinflammation, and brain senescence, linking eNOS to COVID-19-related neuropathology. Full article

Pigs are affected by a variety of pathogenic agents that need to be identified correctly and diagnosed even when co-infections may complicate the application of specific and targeted assays. Next-generation sequencing can provide new perspective to monitor viruses infecting or co-infecting diseased pigs. In this study, we tested, for the first time for diagnostic purposes in a livestock species, a new method based on whole-genome sequencing of all the DNAs extracted from the blood of nine pigs sampled from a farm where there was a suspected outbreak of Post-weaning Multisystemic Wasting Syndrome. We then used unmapped reads on the porcine reference genome to mine for viral sequences using a specifically designed bioinformatic pipeline. Within this fraction of reads, viral sequences ranged from 0.002% to 4.4% of the total unmapped reads and were derived from twelve different viruses known to infect pigs, where three were herpesviruses, eight were parvoviruses, and one was a circovirus. All pig sequencing datasets were positive for one or more viruses, with various potential viral loads. Suid betaherpesvirus 2, also known as Porcine cytomegalovirus (PCMV), was the most frequently identified virus as five out of the nine pig sequencing datasets contained viral sequences from this virus. The results may suggest a heterogeneous viral profile of the diseased pigs that may be derived from potential secondary infections or co-infections. This pilot application demonstrated that a whole-genome sequencing approach can complement other routine diagnostic assays in veterinary virology. Other studies and improvements are needed to validate the results and apply this approach in routine monitoring applications. Full article

Fish red blood cells (RBCs) are nucleated, transcriptionally active, and key players in both gas transport and immune responses. They are the primary targets of Orthoreovirus piscis (PRV), the etiological agent of heart and skeletal muscle inflammation (HSMI), which includes three genotypes (PRV-1, PRV-2, and PRV-3), linked to circulatory disorders in farmed salmon. In Chile, PRV-3 affects the coho salmon (Oncorhynchus kisutch), but host–pathogen interactions remain poorly characterized. This study compared the interactions of PRV-3 in coho salmon and PRV-1 in Atlantic salmon (Salmo salar) using RBC infection models. RBCs were isolated from healthy juvenile salmon (n = 3) inoculated with either PRV-1 (Ct = 18.87) or PRV-3 (Ct = 21.86). Poly I:C (50 µg/mL) was used as a positive control for the antiviral response. Cells were monitored for up to 14 days post-infection (dpi). PRV-3 infection in coho salmon RBCs caused significant metabolic disruption, apoptosis from 7 dpi, and correlated with increasing viral loads. In contrast, PRV-1 infection in Atlantic salmon RBCs showed limited apoptosis and maintained cell viability. Coho salmon RBCs upregulated rig-i, mx, and pkr transcripts, indicating activation of the type I interferon pathway, whereas Atlantic salmon RBCs exhibited a more attenuated response. PRV-3 induced notable morphological changes in coho salmon RBCs, although neither PRV-3 nor PRV-1 caused hemolysis. These findings highlight species-specific differences in RBC responses to PRV infection and provide new insights into the pathogenesis of PRV-3 and PRV-1. Full article

Background: Vietnam has made significant strides in reducing the prevalence of HIV infection and achievements in its antiretroviral treatment program. However, the COVID-19 pandemic and financial challenges in the healthcare system have posed significant obstacles to maintaining effective HIV treatment and monitoring, particularly among vulnerable populations. This study aims to evaluate the situation of HIV drug resistance among patients who have experienced treatment failure in the Mekong Delta region and to compare data from 2019 to 2022. Methods: The study material was blood plasma samples from HIV-infected individuals with ART failure: 316 collected in 2019 and 326 collected in 2022. HIV-1 genotyping and mutation detection were performed based on an analysis of the nucleotide sequences of the Pol gene region. A total of 116 HIV-infected individuals with virological failure in 2019 and 2022 were assessed for HIV drug resistance. Results: The study revealed a high proportion of participants with viral loads exceeding 1000 copies/mL, significantly increasing from 12.0% in 2019 to 23.9% in 2022 (OR = 2.3; p = 0.0001). HIV drug resistance mutations were detected in 84.21% of cases in 2019 and 92.59% in 2022. The prevalence of concurrent resistance to NRTIs and NNRTIs was 37.5% and 30.13% in 2019 and 2022, respectively. There was a statistically significant decrease in NNRTI resistance (OR = 0.32, χ² = 5.43, p < 0.05). In contrast, multi-drug resistance to protease inhibitors rose from 18.52% to 45.21% (φ* = 0.00403, p < 0.05). Triple-class resistance was identified only in 2022 (17.81%). The most common mutations included M184I/V, D67N, K103N, Y181C, and V82A/S/T, with D67N rising significantly from 3.13% to 21.92%. The predominant subtype was CRF01_AE. Conclusion: A high prevalence of viral non-suppression and HIV drug resistance was observed among patients in the Mekong Delta region, particularly after the onset of the COVID-19 pandemic. Our study highlights the ongoing challenges that the HIV/AIDS treatment program in Vietnam must address in the post-pandemic period to sustain its success and achieve the goals of the country’s HIV prevention strategies. Full article

Background: Understanding immune response is essential for preparing for public health crises. COVID-19 vaccination provides robust immunity against SARS-CoV-2, but immunocompromised populations may have weaker immune responses. We assessed SARS-CoV-2 spike (trimer) total IgG/IgM/IgA (total Ig) to investigate immune response to COVID-19 vaccination in people living with HIV (PLWH), considering CD4⁺ T cell count, viral load, substance use, and comorbidities. Methods: This cross-sectional study was conducted in Miami, Florida, between May 2021 and December 2021 as part of the NIH Rapid Acceleration of Diagnostics-Underserved Populations (RADx-UP) initiative (3U01DA040381-05S1) and the Miami Adult Studies on HIV (MASH) cohort (U01DA040381). Blood samples were collected and SARS-CoV-2 spike (trimer) total Ig was quantified. HIV serostatus, viral load, CD4⁺ T cell count, and COVID-19 vaccinations were abstracted from medical records. Substance use (tobacco, alcohol, and drug use [marijuana, cocaine, heroin, fentanyl, methamphetamine, amphetamine, hallucinogens, ecstasy, or misuse of prescription drugs]), and comorbidities (hypertension, diabetes, autoimmune disease, obesity, chronic kidney disease, and substance use disorders) were assessed via validated questionnaires. Drug use was confirmed via urine toxicology. Multivariable linear regression was conducted. Results: Median age (n = 1317) was 57.8 years, 49.8% were male, 50% were Black non-Hispanic, 66.2% had received ≥1 dose of a COVID-19 vaccine, and 29.6% were PLWH (71.3% virally suppressed and median CD4⁺ T cell count > 500 cells/µL). PLWH, compared to people without HIV, were more likely to have received ≥1 dose of a COVID-19 vaccine (76.2% vs. 62.0%, p < 0.001) and present with substance use (77.2% vs. 42.9%, p < 0.001) and comorbidities (72.8% vs. 48.2%, p < 0.001). Vaccinated PLWH, compared to unvaccinated PLWH, had higher CD4⁺ T cell counts (577.5 vs. 517.5, p = 0.011) and were more likely to be virally suppressed (76.4% vs. 54.8%, p < 0.001). A lower CD4⁺ T cell count (<200 vs. ≥500, β = −0.400, p = 0.033) and higher HIV viral load (≥200–<5000 vs. <200, β = −0.275, p < 0.001) were associated with lower spike (trimer) total Ig titers, indicating a diminished response to COVID-19 vaccination. Conclusions: A lower CD4⁺ T cell count and higher HIV viremia were linked to reduced SARS-CoV-2 immunogenicity in racial/ethnic minority PLWH, a population underrepresented in vaccine clinical trials. HIV care providers should target efforts to maintain viral suppression to avoid diminished responses to COVID-19 vaccination. Full article

Background: Asymptomatic congenital cytomegalovirus (acCMV) infections represent 85–90% of all congenital CMV infection. The incidence of late-onset sequelae in these cases significantly contribute to the burden of CMV disease. The timing of maternal infection (TMI) has been identified as the main predictor of late-onset sequelae in acCMV infants, and follow-up programs in Europe are currently calibrated according to the TMI. Our aim was to evaluate neonatal viremia as a possible predictor of the TMI in acCMV infections. Methods: Plasma viral loads (PVLs) were assessed in the first month of life in a population of acCMV-infected newborns delivered by women who suffer a primary CMV infection during pregnancy. TMI was assigned to a trimester of pregnancy according to the maternal serological screening. PVLs were evaluated in relation to the TMI and gestational age (GA) at birth. Results: One hundred and ten newborns were, respectively, assigned to preconceptional (6.4%), 1st (27.3%), 2nd (38.2%), and 3rd (28.2%) trimester infections. Median neonatal PVLs values were significantly different between groups (p < 0.001). First-trimester infections exhibited significantly higher PVLs when compared with third-trimester ones (p < 0.001). Overall, PVLs showed an inverse correlation with GA at birth (p = 0.003). Conclusions: Median neonatal PVLs are significantly higher in 1st trimester infections if compared with 3rd trimester ones, but a wide overlap between PVL values prevent their possible use as a predictor of the TMI. In our population, a significant inverse relationship, mainly dependent on 1st and 2nd trimester infections, is demonstrated between PVLs and GA. Overall, fetal viremia is already decreasing weeks before the term of pregnancy. Full article

Background/Objectives: Helminth infections, particularly prevalent in low- and middle-income countries, have been extensively studied for their effects on human health. With the emergence of new infectious diseases like SARS-CoV-2 and Ebola, their impact on disease outcomes become more apparent. While individual studies have explored the impact of helminth co-infections on disease severity and vaccine efficacy, the findings are often inconsistent and context-dependent. Furthermore, the long-term effects of helminth-mediated immunosuppression on vaccine efficacy and its broader implications for co-infections in endemic regions remain not fully understood. Methods: This systematic review conducted in line with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines synthesizes the current evidence, identifies patterns, and highlights areas needing further research, offering a cohesive understanding of the topic. PubMed, Scopus, Google Scholar, and Cochrane Library were searched to include studies published from 2003 to February 2025. Results: Co-infection reveals a dual role of helminths in modulating immune responses, with both beneficial and detrimental interactions reported across studies. It may confer benefits against respiratory viral infections by muting hyper-inflammation associated with the severity of conditions like COVID-19, Influenza, and RSV. However, they can exacerbate disease outcomes in most bacteria and blood-borne viral conditions by impairing immune functions, such as neutrophil recruitment and antibody response, leading to more severe infections and higher viral loads. The stage of helminth infection also appears critical, with early-stage infections sometimes offering protection, while late-stage infections may worsen disease outcomes. Helminth infection can also negatively impact vaccine efficacy by suppressing B cell activity, reducing antibody levels, and decreasing vaccine effectiveness against infectious diseases. This immunosuppressive effect may persist after deworming, complicating efforts to restore vaccine efficacy. Maternal helminth infections also significantly influence neonatal immunity, affecting newborn vaccine responses. Conclusions: There is a need for targeted interventions and further research in helminth-endemic regions to mitigate the adverse effects on vaccine efficacy and improve public health outcomes. Full article

Background: COVID-19, caused by SARS-CoV-2, poses a significant threat to human health. Vaccines designed for T-cell epitopes play an important role in eliminating the virus. However, T cell epitope screening often requires the use of a large number of peripheral blood mononuclear cells (PBMCs) from infected or convalescent patients, and if MHC humanized mice can be used for epitope screening, they will not have to wait for enough PBMCs to be available to screen for epitopes, thus buying time for epitope confirmation and vaccine design. Methods: In this study, we used SARS-CoV-2 BA.5 to infect HLA-A11/DR1, C57BL/6, hACE2 mice, and detected body weight changes, viral load, and pathological changes after infection. Fourteen days after the HLA-A11/DR1 and C57BL/6 mice were immunized against inactivated viruses, IgG antibodies were detected in mouse serum using ELISA, and IFN-γ produced by peptide stimulation of splenocytes was detected by ELISpot. Results: There is no obvious pathogenic phenotype of SARS-CoV-2 infection in HLA-A11/DR1 mice. Specific IgG antibodies were detected in serum after immunization of inactivated virus in both HLA-A11/DR1 and C57BL/6 mice, but specific IFN-γ was detected in splenocytes of HLA-A11/DR1 mice. Conclusions: Although HLA-A11/DR1 mice are unable to replicate the virus effectively in vivo, they are able to generate cellular immune responses after immunization inactivated viruses. Therefore, it can be used as a tool to substitute for human PBMCs in epitope screening, thus shortening the timeliness of T cell epitope screening and obtaining the immunogenicity information of new epitopes in a timely manner. Full article