Search Results (288)

Respiratory pathogens are significant causes of morbidity and mortality worldwide. Since the emergence of SARS-CoV-2 in 2019 and the mitigation measures implemented to control the pandemic, other respiratory viruses’ transmission and circulation patterns were substantially disrupted. We leveraged the influenza hospitalization surveillance in Tanzania to understand the distribution of respiratory viruses shortly after nonpharmaceutical interventions (NPIs) were lifted. A total of 475 samples that tested negative for SARS-CoV-2 and influenza from March through May 2022 were included in this study. The samples were tested for 16 virus targets using Anyplex II RV16 multiplex assays. The findings indicate that most hospitalizations (74%) were among children under 15 years, with human bocavirus (HBoV) being the most prevalent (26.8%), followed by rhinovirus (RV, 12.3%), parainfluenza viruses (PIVs1–4, 10.2%), respiratory syncytial virus (RSV, 8.7%), adenovirus (AdV, 4.3%), and metapneumovirus (MPV, 2.9%). Notably, 54% of respiratory hospitalizations had no viruses detected. The findings highlight the broad circulation of respiratory viruses shortly after NPIs were lifted in Tanzania. Surveillance for respiratory pathogens beyond influenza and SARS-CoV-2 can inform public health officials of emerging threats in the country and should be considered an important pandemic preparedness measure at a global level. Full article

Background/Objectives: While adenovirus (Ad) therapies have been proven to be effective in local administration, systemic Ad treatments have shown limited success due to pre-existing antibodies in the human blood that neutralize the virus. We developed a liposome coating procedure that protects the Ad from pre-existing neutralizing antibodies in human blood. To assess the in vivo stability of the liposomes, the present study used a novel in vivo method to quantitatively assess the protective capabilities of liposome-encapsulated Ad (DfAd) from neutralizing antibodies. Methods: The assay systemically administers DfAd with a green fluorescent protein transgene (DfAd-GFP) into pre-immunized mice and allows it to circulate in the presence of neutralizing antibodies; the infected blood is extracted and used to transduce HEK293 cells, which emits fluorescence in the presence of protected, un-neutralized Ad. Results: The PEGylated liposome formulation provides 12× protection in vivo relative to unencapsulated Ads. In vitro optimization of the liposome coating reveals a strong correlation between the structural stability of liposomes and protection against anti-Ad neutralizing antibodies, where DSPE-PEG2000-carboxylic acid (DSPE-PEG2000-CA) is a critical component for liposome stability and increasing protection against antibody neutralization of the encapsulated Ad. Conclusions: The findings in the present study confirm that the DfAd liposome can protect against neutralizing antibodies in blood circulation. The novel in vivo assay for liposome protection against neutralizing antibodies and in vitro experiments in the present study provide new tools and insights toward designing liposome–Ad complexes for the systemic treatment of cancer. Full article

Adenovirus is a frequent cause of mild, usually self-limited infections in infants and young children. Severe infections occur in immunocompromised patients but are rarely observed in healthy, immunocompetent adults. However, there have been outbreaks of infections with different adenoviral (Ad) types around the world that have resulted in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) in some of those infected. Ad14p1 is the predominant circulating strain of Ad14 worldwide that has caused ARDS. An explanation for the severity of illness caused by Ad14p1 infection in immunocompetent patients is unknown. Previously, we have shown that A549 cells infected with Ad14 repress macrophage pro-inflammatory responses, whereas cells infected with Ad14p1 fail to repress macrophages and instead can increase pro-inflammatory responses. Adenoviral infection has been shown to modulate host miRNA expression, and we hypothesized that differences in miRNA expression between Ad14- and Ad14p1-infected cells might explain the differential responses of macrophages to Ad14- and Ad14p1-infected cells. Analysis of host miRNA showed that 98 miRNAs are differentially expressed when infection reaches full cytopathic effect (CPE), the same point at which Ad14 and Ad14p1 CPE corpses induce differential inflammatory responses in macrophages. Only 10 of the miRNAs that were enriched in Ad14 CPE corpses were expressed at levels that are potentially biologically relevant. Pathway enrichment analysis showed that the differentially expressed miRNAs might explain the increased pathogenesis of Ad14p1 through strain-related loss of modulation of cytokine expression when compared with prototype Ad14. Overall, the data suggest a role for viral regulation of host miRNA expression in pathogenesis by regulating host inflammatory responses through the delivery of de-regulated miRNAs by viral CPE corpses to macrophages. Full article

Two main adenoviral diseases have been described in pigeons: pigeon adenovirus type 1 (PiAdV-1) and pigeon adenovirus type 2 (PiAdV-2), which belong to the genus Aviadenovirus under the family Adenoviridae. PiAdV-1 and PiAdV-2 are highly pathogenic to pigeons, leading to considerable losses worldwide. To date, there is little information on the epidemiological distribution of PiAdV-1 and PiAdV-2 in pigeons due to the lack of detection and differentiation platforms for these two viruses. High-resolution melting technology (HRM) has been widely used for developing detection and differentiation platforms, with the melting profile based on the GC content in the real-time PCR (qPCR-HRM) system. This study designed and synthesized a pair of specific primers on the basis of the characteristic variations of the 52K genes of PiAdV-1 and PiAdV-2, then the detection and differentiation qPCR-HRM platform was established after conditional optimization. The results showed that this method had good specificity; it could only specifically detect PiAdV-1 and PiAdV-2, with no cross-reaction with other pigeon-origin pathogens that occur in pigeons. This method had high sensitivity, with the lowest detection limits at 57 copies/µL (for PiAdV-1) and 56 copies/µL (for PiAdV-2). This method had good intra-group and inter-group coefficients of variation, both of which were less than 1.5%. Field samples for the epidemiological surveillance and investigation data of PiAdV-1 and PiAdV-2 were checked. We found only PiAdV-2-positive samples in meat pigeons, but the percentages of PiAdV-1-positive, PiAdV-2-positive, and coinfection-positive samples among the racing pigeons were 5.71%, 14.29%, and 2.86%, respectively. To our knowledge, this is the first report for the simultaneous detection and differentiation of PiAdV-1 and PiAdV-2 using the qPCR-HRM platform. Our study also provided evidence of PiAdV-1 and PiAdV-2 coinfection in racing pigeons, but further studies are needed. Full article

Background/Objectives: Respiratory syncytial virus (RSV) poses a substantial global health threat, particularly impacting infants and vulnerable pediatric populations through severe respiratory morbidity. Methods: We developed a novel adenoviral vector vaccine platform utilizing chimpanzee adenovirus 68 (AdC68) to deliver prefusion F (pre-F) antigens from RSV subtypes A and B, generating three vaccine candidates: AdC68-A (subtype A), AdC68-B (subtype B), and AdC68-A+B (bivalent formulation). Results: Single intranasal (i.n.) immunization and prime–boost immunizations via intramuscular (i.m.) routes in BALB/c mice induced robust immune activation, with single i.n. administration conferring durable protection evidenced by an 85% reduction in pulmonary viral loads (p < 0.05) at 134 days post-immunization. All vaccine formulations via i.n. single administration elicited potent subtype-specific IgG responses (geometric mean titers 50–12,800) and Th1-polarized cellular immunity (552–1201 IFN-γ+ spot-forming units/10⁶ PBMCs, IgG2a/IgG1 > 1) in bivalent formulation group, while i.m. boosting enhanced cellular responses 3-fold versus prime immunization alone (p < 0.01). Notably, despite undetectable serum-neutralizing antibodies and absent mucosal IgA in bronchoalveolar lavage at 7 days post-i.n. immunization, the sustained viral control highlights non-neutralizing antibody-mediated protective mechanisms. Conclusions: These findings establish the proof-of-concept for adenoviral-vectored intranasal vaccines against RSV, though optimization of humoral response induction and mucosal immunity duration require further investigation. Full article

Adenovirus (AdV) infections can lead to significant morbidity and increased mortality in immunocompromised populations such as hematopoietic stem cell and solid organ transplant recipients. This review evaluates currently available and emerging therapies for AdV infections. Cidofovir, while most commonly used, is limited by its variable efficacy and nephrotoxicity. This led to the development of brincidofovir, which has a better safety profile and great in vitro potency against AdV. The use of ribavirin and ganciclovir has been reported in the literature, but their use is limited due to inconsistent efficacy. Immune-based approaches, such as adoptive T-cell therapy, have shown promise in achieving viral clearance and improving survival but remain constrained by challenges related to manufacturing complexity and risks of graft-versus-host disease. This review underscores the need for standardized treatment protocols as well as comparative studies to identify optimal dosing and timing to initiate treatment. Future research should focus on individualized treatment approaches and the development of novel therapeutic agents to address the unmet clinical needs of AdV management. Full article

The insertion of a transgene downstream of the L3-23K or L5-Fiber region was reported as a vital strategy for arming E3 non-deleted oncolytic adenoviruses. However, depending on the percentage of codons with G/C at the third base position (GC3%) and the type of splicing acceptor, an insert downstream of the L5-Fiber region may substantially affect virus fitness. Since the insertion of transgenes downstream of the L3-23K and L5-Fiber regions has never been compared in terms of their expression levels and impact on virus fitness, we assessed the total virus yield, cytolytic efficacy, and plaque size of Ad5-delta-24-RGD (Ad5Δ24RGD) armed with EGFP, FLuc, the suppressor of RNA silencing p19, soluble wild-type human/mouse and high-affinity human programmed cell death receptor-1 (PD-1/PDCD1) ectodomains, and soluble human hyaluronidase PH20/SPAM1. The insertion of transgenes downstream of the L3-23K region ensures their production at considerably higher levels. However, the insertion of transgenes downstream of either region differentially and unpredictably affects the oncolytic potency of Ad5Δ24RGD, which cannot be explained by GC3% or expression level alone. Surprisingly, the expression of the human and mouse PD-1 ectodomains with 83.1% and 70.1% GC3%, respectively, does not affect cytolytic efficacy but increases the plaque size in a cell line-dependent manner. Full article

This review systematically revises adenovirus (Ad) biology, vector structure, immune responses, and currently available Ad vector COVID-19 vaccines. It analyzes the challenges associated with the Ad vector-based vaccines, including preexisting vector immunity and other side effects. Moreover, this review explores novel and innovative strategies to overcome these constraints for developing next-generation vaccines for broad protection to cover emerging SARS-CoV-2 variants. The future refinement of Ad vaccine platforms will be pivotal in achieving durable immunity against emerging variants for global preparedness. Full article

Rabies is a zoonotic viral disease that is preventable through vaccination. Effective control strategies should follow the “One Health” concept, as targeting zoonotic pathogens at their animal source is the most effective and cost-efficient approach to protecting human health. The aim of this study was to develop and evaluate two third-generation anti-rabies vaccines based on non-replicative viral vectors, MVA and Ad5, both expressing rabies virus (RABV) glycoprotein (MVA-RG and Ad-RG). MVA-RG was produced using a platform developed in our laboratory, while Ad-RG was generated using a commercial kit. Protection against rabies was assessed in a mouse intracerebral (IC) RABV challenge model. Our results demonstrated that both vectors provided protection against RABV. MVA-RG and Ad-RG administered in two homologous doses conferred 60% and 60–100% protection against RABV challenge, respectively. The survival rate was influenced by the viral vector, the dose, and the immunization scheme. Remarkably, to our knowledge, our study is the first to report 100% protection against IC RABV challenge using a non-replicative Ad5 in a homologous immunization scheme. These promising results support future evaluation of this vaccine candidate in target animals. Full article

Background: Pre-existing adenovirus immunity restricts the utilization of adenovirus-vectored vaccines. The current study aims to conduct a pooled analysis of eight clinical trials to evaluate the influence of pre-existing Ad5 neutralizing antibodies on immunogenicity of Ad5-nCoV. Methods: The primary outcome indicator of this pooled analysis is the geometric mean titers (GMTs) of live SARS-CoV-2 NAbs against the wild-type strain on day 28 post-vaccination. Participants were divided into two cohorts: an adolescent cohort comprising individuals aged 6–17 years and an adult cohort with individuals aged 18 years and older. Within each cohort, individuals were further categorized into three subgroups based on their Ad5-nCoV vaccination schedules: one subgroup received a single intramuscular dose as the primary regimen (Ad5-IM-prime), another received an intramuscular dose as the heterologous prime-boost regimen (Ad5-IM-boost), and the last subgroup received an aerosolized dose as the heterologous prime-boost regimen (Ad5-IH-boost). Results: A total of 3512 participants were included in this pooled analysis. In the Ad5-IM-prime subgroup, there were 1001 adolescents and 1450 adults; in the Ad5-IM-boost subgroup, there were 65 adolescents and 396 adults; and in the Ad5-IH-boost subgroup, there were 207 adolescents and 393 adults. In the adult cohort, the GMTs of NAbs against wild-type SARS-CoV-2 on day 28 post-vaccination for the Ad5-IM-prime, Ad5-IM-boost, and Ad5-IH-boost subgroups were 35.6 (95% CI: 32.0, 39.7), 358.3 (95% CI: 267.6, 479.6), and 2414.1 (95% CI: 2006.9, 2904.0), respectively, with negative (less than 1:12) pre-existing NAb titers compared to 10.7 (95% CI: 9.1, 12.6), 116.9 (95% CI: 84.9, 161.1), and 762.7 (95% CI: 596.2, 975.8), respectively, with high (greater than 1:1000) pre-existing NAb titers. A similar trend was observed in the adolescent cohort, where pre-existing immunity was found to reduce the peak of live SARS-CoV-2 Nabs post-vaccination. Conclusions: Regardless of whether Ad5-nCoV is administered as a primary vaccination regimen or as a heterologous prime-boost strategy, a negative impact on immunogenicity can still be observed in the presence of high pre-existing immunity. However, when primary immunization is achieved with inactivated COVID-19 vaccines, aerosol inhalation can significantly enhance the immunogenicity of Ad5-nCoV compared to intramuscular injections of Ad5-nCoV as a booster. Full article

Background/Objectives: The use of virus-like particles (VLPs) in vaccinology has expanded significantly in recent years. VLPs have the advantage of being non-infectious while effectively stimulating B cell responses through the repetitive presentation of epitope motifs on their surface. Since VLPs are often derived from human-infecting viruses, preexisting immunity may influence the immune response they elicit, warranting further investigation. Methods: We have developed a 60-mer VLP derived from human adenovirus type 3, a common pathogen. We investigated the impact of pre-existing adenovirus immunity on the immunization outcome against the linear S14P5 epitope of SARS-CoV-2, which was engineered into the particle (Ad-VLP-S14P5). To this end, antibody responses to S14P5 were evaluated following immunization with Ad-VLP-S14P5 in either naive or vector-primed mice. Results: Mice with pre-existing anti-vector immunity exhibited significantly greater anti-S14P5 antibody responses compared to vector-naive animals, demonstrating a beneficial impact of prior anti-adenovirus responses. However, the addition of an oil-in-water adjuvant for the immunizations abolished this positive impact, even leading to a deleterious effect of the pre-existing anti-vector immunity. Conclusions: The data suggest that the immune status against immunizing VLPs must be taken into consideration when designing immunization protocols. Importantly, the effects of prior immunity may vary depending on the nature of the protocol, including factors such as adjuvant use. Full article

Despite annual vaccines, Influenza B viruses (IBVs) continue to cause severe infections and have a significant impact and burden on the healthcare system. Improving IBV vaccine effectiveness is a key focus, with various strategies under investigation. In this research, we used a computational design to select wildtype sequences for a multivalent viral-vectored vaccine (rAd-Tri-Vic) targeting the Victoria-like (Vic) hemagglutinin (HA) protein. In mouse models, the vaccine induced strong antibody and T cell responses, providing complete protection against both lineage-specific and cross-lineage (Yamagata-like) lethal challenges. The immune responses remained robust for up to six months, which demonstrated sustained protection. These results highlight the potential of HA-targeted multivalent vaccines to enhance the IBV efficacy and address protection against antigenically diverse IBV strains. Full article

In this study, we present an oncolytic virus (OV) evaluation system established using microfluidic organ-on-a-chip (OOC) systems and patient-derived organoids (PDOs), which was used in the development of a novel oncolytic virus, AD4-GHPE. An OV offers advantages such as good targeting ability and minimal side effects, and it has achieved significant breakthroughs when combined with immunotherapy in recent clinical trials. The development of OVs has become an emerging research focus. PDOs can preserve the heterogeneity of in situ tumor tissues, whereas microfluidic OOC systems can automate and standardize various experimental procedures. These systems have been applied in cutting-edge drug screening and cell therapy experiments; however, their use in functionally complex oncolytic viruses remains to be explored. In this study, we constructed a novel recombinant oncolytic adenovirus, AD4-GHPE, and evaluated OOC systems and PDOs through various functional validations in hypopharyngeal and breast cancer organoids. The results confirmed that AD4-GHPE exhibits three antitumor mechanisms, namely, tumor-specific cytotoxicity, a reduction in programmed death ligand 1 (PD-L1) expression in tumor cells to increase CD8⁺ T-cell activity, and granulocyte–macrophage colony-stimulating factor (GM-CSF) secretion. The evaluation system combining OOC systems and PDOs was efficient and reliable, providing personalized OV treatment recommendations for patients and offering industrialized and standardized research ideas for the development of OVs. Full article

Monitoring immune function in post-transplant patients is crucial to reduce the risk of viral infections (e.g., cytomegalovirus [CMV] or Epstein–Barr virus [EBV]), which can lead to serious complications such as post-transplant lymphoproliferative disorder (PTLD). Recently, Torque Teno virus (TTV) has attracted interest as a marker of immune function. Thus, we studied the kinetics of common post-transplant viral infections (TTV, EBV, CMV, human herpesvirus-6 [HHV-6], and adenovirus [AdV]) and their association with clinical parameters in 23 HSCT recipients who developed PTLD (PTLD-HSCT) and 25 post-HSCT patients without PTLD (Non-PTLD-HSCT) at three different timepoints: at the time of the transplant (T0), 3 months (T1), and 6 months (T2) post-HSCT. Additionally, 25 healthy donors (HD) were used as the control. EBV, CMV, HHV-6, or AdV infections were found in a few samples, while TTV was found in all of our samples. The highest TTV levels (4.61 [T0], 6.24 [T1] and 6.70 [T2] log₁₀ copies/mL) were seen in PTLD-HSCT patients compared to Non-PTLD-HSCT (3.39 [T0], 4.86 [T1], and 3.75 [T2] log₁₀ copies/mL) and HD (2.25 log₁₀ copies/mL) at all timepoints. Higher TTV levels were also seen in patients with a destructive type of PTLD and in surviving PTLD-HSCT patients compared to deceased ones. TTV kinetics in PTLD patients post-HSCT showed that TTV levels increase with the fall in the host immunocompetence and that by monitoring TTV kinetics, the immune status of the patient can be monitored. Full article

Cholangiocarcinoma (CCA), the second most common liver cancer, remains highly resistant to chemotherapy and radiotherapy, leaving patients with unresectable tumors in urgent need of innovative therapeutic approaches. Adenovirus type 6 (Ad6), a species C human adenovirus, offers significant potential for cancer therapy due to its low seroprevalence compared to Adenovirus type 5 (Ad5) and its ability to evade Kupffer cells during systemic delivery. In this study, we developed a novel oncolytic adenovirus vector based on the Ad6 engineered to express human GM-CSF (Ad6-d24-GM) and evaluated its therapeutic efficacy in a novel immunocompetent, replication-permissive Syrian hamster model of CCA. Intratumoral administration of Ad6-d24-GM significantly suppressed tumor growth and prolonged survival without evidence of toxicity, as indicated by stable body weights and normal liver enzyme levels. Both Ad6-d24-GM and wild-type Ad6 induced robust infiltration of CD4+ and CD8+ T cells, as well as CD68+ macrophages within tumors, demonstrating activation of antitumor immunity. Notably, the Ad6-d24-GM group exhibited a statistically significant increase in CD68+ cells compared to wild-type Ad6, highlighting the immunomodulatory effect of GM-CSF transgene. These results demonstrate the oncolytic and immunostimulatory potential of Ad6-based vectors for CCA treatment and validate the Syrian hamster syngeneic CCA-OF model as a valuable platform for studying oncolytic adenovirus therapies. Full article