Biology subjects

Kipar, A.

Publications and source records attributed to Kipar, A..

At least 19 recordsLinked to original sources

bioRxiv2026

Histopathological and virus-associated features of Boid Inclusion Body Disease in Boa constrictor

Boid inclusion body disease (BIBD) is a reptarenavirus-induced fatal disease of boid snakes that, while diagnosed with ease due to the pathognomonic intracytoplasmic inclusion bodies (IB), is not yet fully characterized pathomorphologically and with regards to its pathogenesis. The present study retrospectively investigated a random cohort of 50 captive male and female boa constrictors of variable age (neonate to 25 years) for histopathological changes and in situ viral protein (nucleoprotein, NP, and glycoprotein 2, GP2) expression patterns. IB formation and NP expression were scored semiquantitatively. The vast majority of snakes (42/50; 84%) exhibited histopathological changes; these mainly (39/42; 93%) represented inflammatory processes that most frequently affected the gastrointestinal tract. Overall, IB and NP scores were significantly higher in the more recent cases (2020-2025) compared to the older cases (2000-2003). NP scores did not differ between age groups or sex, but were lower in animals with clinical signs and higher in those with histopathological changes. No statistically significant association was found between NP scores and inflammatory processes, neither in general nor in individual organs. GP2 expression, as an indicator of virion assembly, was less consistent than NP expression and generally restricted to individual cells with and without IBs. There was no histological evidence of overt damage in infected cells. Jointly, the results indicate different phases of restrictive and systemic viral replication that are not directly associated with pathological processes and/or clinical signs.

pathology↗

bioRxiv2026

The biodistribution and effect of post-exposure neutralising monoclonal antibody treatment in a mouse model of SARS-CoV-2 infection with viral spread to the brain

Ronapreve, a combination of two neutralising monoclonal antibodies, casirivimab and imdevimab, was amongst the authorised treatments against SARS-CoV-2 early in the COVID-19 pandemic. Ronapreve has lost some of its efficiency with the rise of new virus variants, however, it remains a valuable tool for experimental studies to gain insights into the mechanisms and effects of anti-viral drugs. In this study we combined morphological, pharmacokinetic and molecular approaches (including multiomics) to investigate the biodistribution of Ronapreve in the K18-hACE2 murine model of SARS-CoV-2 neuroinvasion, as well as possible consequences for the brain. We also investigated the effect of the treatment on the infection status. Our results showed that after intraperitoneal injection, Ronapreve accumulates in the serum and is unable to cross the blood-brain barrier, thus not reaching the brain parenchyma; treatment has only a minimal effect on the brain transcriptome, with no significant changes in the brain lipidome or metabolome. Nonetheless, post-exposure Ronapreve treatment resulted in reduced viral loads in the lung and, in particular, the brain, with markedly reduced tissue response in the brain, as shown by the transcriptomic analysis. The results suggest a peripheral mode of action of Ronapreve to block brain infection, possibly by lowering viral replication in the nasal epithelium, reducing a subsequent spread to the brain.

pathology↗

bioRxiv2026

Snake Kolmiovirus Encodes a Single Form of Delta Antigen and Shows No Evidence of Translation from Open Reading Frame 2

Hepatitis D virus (HDV) is a satellite virus that utilizes hepatitis B virus (HBV) as a helper for infectious particle formation. HDV was originally identified as a novel antigen in liver biopsies of HBV patients, and later studies showed the "delta" antigen (DAg) to be the sole protein encoded by HDV. Until the discovery of HDV-like agents in birds and snakes in 2018, HDV was a unique example of animal satellite viruses. We identified Swiss snake colony virus 1 (SwSCV-1) in the brain of a Boa constrictor, and through comparison we found the genome organization of SwSCV-1 to resemble that of HDV. However, in addition to the DAg open reading frame (ORF), the genome of SwSCV-1 includes another >500 nt ORF, "ORF2". To study whether the putative ORF2-encoded protein plays a role in the SwSCV-1 life cycle, we established an infectious clone of the virus with a point mutation in the methionine initiation codon of ORF2. The mutation did not significantly affect initiation of replication, establishment of persistent infection, or infectious particle formation upon superinfection with a helper virus. Using additional methods, we gathered further evidence confirming that ORF2 is not actively translated in boa constrictor cells. We further showed that unlike HDV, SwSCV-1 expresses a single form of the DAg. Although the proteins encoded by SwSCV-1 and HDV only include one and two forms of the DAg, respectively, whether other kolmioviruses express additional forms of DAg or related proteins in some cell types or host species merits further research. IMPORTANCEApproximately 40 years after the discovery of hepatitis D virus (HDV), satellite viruses with similar genome organization were found in various animals, thereby giving rise to family Kolmioviridae. HDV encodes a single protein, the delta antigen (DAg), which comes in small and approximately 20 amino acids longer large form. The genome of some HDV species and many of the newly found kolmioviruses contains additional open reading frames (ORFs), potentially enabling protein expression. Here, we studied the viral proteins expressed during Swiss snake colony virus 1 (SwSCV-1) infection of boa constrictor cells. Our findings show that unlike HDV, SwSCV-1 encodes only a single form of DAg. In addition, our study suggests that, like in HDV, the additional ORF in SwSCV-1 genome does not give rise to a protein. Although we could not demonstrate expression of additional viral proteins during SwSCV-1 infection, it is important to study the proteome of other kolmioviruses.

microbiology↗

bioRxiv2026

Nanobodies against the S2 region of the spike protein potently neutralize SARS-CoV-2 viruses and show resistance to virus escape

Entry of coronaviruses into cells is mediated by the viral spike (S) glycoproteins each consisting of S1 receptor binding and S2 membrane fusion subunits. The sequence of the S2 region is very highly conserved amongst variants of SARS-CoV-2 and compared to the S1 unit shares significant sequence identity amongst different beta-coronavirus lineages. By targeting the S2 of SARS-CoV-2 we have identified two selective and potent neutralizing nanobodies (BA.1-C2 and BA.1-D3) that bind to two different quaternary epitopes in the S2 formed by the Heptad Repeat 2 (HR2) trimer at the base of the spike protein. The HR2 sequence is identical in SARS-CoV and SARS-CoV-2 but differs in other beta-coronaviruses explaining the lack of binding to the spike proteins of MERS-CoV or HuCoV-OC43. No viral escape was observed following serial passaging of SARS-CoV-2 (JN.1) with a combination of BA.1-C2 and BA.1-D3 and the most potent of these nanobodies reduced viral load in the hamster model of COVID-19, following intranasal administration. Overall, the results show the value of nanobody technology for identifying novel neutralising epitopes in the S2 region of beta-coronaviruses with potential for the development of new selective anti-viral agents.

molecular biology↗

bioRxiv2025

The pharmacokinetics, bio-distribution and therapeutic efficacy of a trimeric nanobody against SARS-CoV-2 in the Syrian golden hamster COVID-19 model

The rapid emergence of SARS-CoV-2 prompted the development of anti-viral therapies and vaccines to combat the COVID-19 pandemic. The continuous emergence of variants of concern has necessitated the development of platforms that can be rapidly adapted. Nanobodies, offer advantages over conventional monoclonal antibodies, including low molecular weight, high antigen-binding affinity, enhanced tissue penetration, blood-brain barrier permeability, and simplified production. Previous studies have demonstrated the efficacy of nanobodies against respiratory viruses such as SARS-CoV-2, respiratory syncytial virus, and influenza A virus in animal models. We previously reported the protective effects of nanobody trimers against SARS-CoV-2. However, pharmacokinetic and biodistribution data for nanobodies remain limited. To address this, we evaluated the efficacy, biodistribution and longevity of action of a nanobody trimer (A8) administered intranasally (IN) or intraperitoneally (IP) in Syrian golden hamsters. Our findings revealed that the A8 trimer reached peak concentrations shortly after administration and was subsequently cleared from the system via both routes. Importantly, early administration of A8 trimer reduced virus mediated weight loss and viral load compared with untreated controls supporting its potential as a therapeutic candidate for SARS-CoV-2 infection.

microbiology↗

bioRxiv2025

Fatal consequences of feline coronavirus infection are associated with virus persistence and a distinct adaptive immune repertoire

The pathogenesis of feline infectious peritonitis (FIP), arising in a minority of cats infected with feline coronavirus (FCoV), is complex and incompletely understood. Without extended use of direct-acting antivirals FIP is invariably fatal, but there is potential for the emergence of anti-viral resistance. To understand host and viral factors associated with FIP, multiple tissues from cats with and without FIP were subjected to RNA sequencing (RNA-seq), and targeted sequencing of the T cell receptor (TCR) repertoire was conducted for mesenteric lymph nodes in a larger cohort. Samples from cats with FIP demonstrated higher expression of genes involved in type I interferon and proinflammatory cytokine signalling, as well as the adaptive immune response, and expression of these genes was highly correlated with FCoV abundance. Analysis of FCoV genomic variation across tissues revealed dynamic within-host evolution of FCoV, and identified distinct mutations associated with systemic virus spread both within and among cats. Assembly of TCR and B-cell receptor (BCR) sequences identified changes in the immune repertoire associated with FIP, highlighting the polyclonality and ineffectiveness of the immune response to FCoV in cats with FIP, and revealing the presence of potentially protective TCR clonotypes in cats without FIP. Together, these results represent the first analysis of immune repertoire in any feline infectious disease and demonstrate naturally occurring within-host evolution of FCoV. These novel insights into a life-threatening systemic coronaviral disease have the potential to transform therapeutic approaches in FIP.

immunology↗

bioRxiv2025

Tmem117, an oligodendrocyte-enriched regulator of NCX activity, links myelin homeostasis to counterregulation and metabolic health.

The counterregulatory response (CRR) to hypoglycemia is a fundamental, evolutionarily conserved homeostatic mechanism orchestrated by the central nervous system (CNS) to ensure survival during glucose scarcity. In individuals with diabetes, this response is frequently impaired, contributing to life-threatening episodes of hypoglycemia. Tmem117 was previously identified in a genetic screen as a promising hypothalamic regulator of CRR. Our previous work highlighted its contribution to CRR through regulation of vasopressin secretion. Here, we reveal that Tmem117 is also enriched in cells of the oligodendrocytic lineage and we characterize the contribution of oligodendrocytic Tmem117 in CRR. We show that depletion of Tmem117 from either all oligodendrocyte lineage cells or only mature oligodendrocytes leads to myelin deficits and male-specific defects in CRR. Furthermore, we reveal that transient, adult-onset depletion of Tmem117 in mature oligodendrocytes is sufficient to induce long-lasting metabolic imbalances in male mice, suggesting that defects in oligodendrocytes and myelin can affect peripheral glucose homeostasis. Mechanistically, we provide for the first-time insights on the function of Tmem117 showing that it regulates intracellular calcium dynamics through its interaction with the sodium-calcium exchanger NCX1. Together, these results redefine our understanding of the cellular contributors to the CRR, highlight the importance of oligodendrocytes in systemic glucose regulation, and position Tmem117 as a promising molecular target for cell-specific manipulation of NCX activity.

neuroscience↗

bioRxiv2025

Hypoxia inducible factors regulate Pneumovirus replication by enhancing innate immune sensing

The immune mechanisms responsible for protection and pathogenesis in pneumoviral infection are not well defined. We demonstrated that pharmacological activation of the hypoxic inducible factor (HIF) signalling axis using Daprodustat limited viral replication through enhanced immune signalling. Transcriptomic analysis revealed HIF augmented activation of innate immune response genes, including interferon-stimulated gene 15 (Isg15), in the lung and spleen of mice infected with pneumonia virus of mice (PVM). In human respiratory syncytial virus (hRSV) infected airway epithelial cells, Daprodustat inhibited viral replication and enhanced ISG15 expression in a HIF-dependent manner. Importantly, inhibition of type I interferon signalling or the RIG-I sensing pathway abrogated the antiviral activity of HIF. Moreover, Daprodustat increased interferon signalling in response to viral RNA, suggesting that HIF inhibits pneumovirus replication through enhancing viral RNA sensing. Mechanistically, Daprodustat reduced N6-methyladenosine modification of viral RNA through upregulation of RNA demethylases, promoting detection by innate immune sensors. This study highlights the intricate interplay between hypoxia and antiviral immunity and offers valuable insights into pneumovirus-host interactions and potential therapeutic interventions. SIGNIFICANCE STATEMENTThis study explores the role of the hypoxic inducible factor (HIF) signalling pathway in limiting pneumoviral infections, such as respiratory syncytial virus (hRSV) and pneumonia virus of mice (PVM). Using Daprodustat, a clinically approved activator of HIF signalling we demonstrated that stimulation of this pathway enhanced innate immune signalling and limited viral replication. Transcriptomic analysis showed that HIF promoted innate immune response genes in mice infected with PVM and human airway epithelial cells infected with hRSV. Importantly, inhibition of type I interferon signalling or the RIG-I sensing pathway abrogated the antiviral activity of HIF. We uncovered a role for HIF to regulate the levels of N6-methyladenosine modification of viral RNA transcripts, resulting in the increased activation of nucleic acid sensing.

microbiology↗

bioRxiv2025

Integrated Histology and Molecular Profiling of Postmortem Human Auditory and Vestibular Organs via a Poly(Methyl Methacrylate)-Based Workflow

Hearing and balance disorders are the most prevalent sensory impairments, affecting hundreds of millions worldwide, yet their underlying cellular and molecular pathologies remain poorly understood. This knowledge gap stems from the inaccessibility of the ears sensory organs--embedded within the temporal bone (TB), the hardest bone in the body--which cannot be biopsied in living patients without causing irreversible damage. Conventional histopathology workflows rely on postmortem en bloc extraction of TBs, followed by lengthy decalcification, celloidin embedding, and manual serial sectioning of these large specimens--a process that takes one to two years, is labor- and cost-intensive, and lacks compatibility with most modern protein, DNA, and RNA assays. Here, we present a rapid, reversible polymethyl methacrylate (rPMMA) workflow that enables advanced molecular histopathology studies on formalin-fixed, calcified TBs. Our protocol uses low-temperature (-40 {degrees}C to +4 {degrees}C) resin embedding, precision near-serial sectioning (10-50 {micro}m) via femtosecond laser microtomy or precision diamond wire sawing, and subsequent deacrylation to fully restore tissue accessibility for high-fidelity histomorphology, multiplexed immunofluorescence, whole-genome sequencing, and in situ mRNA detection (RNAscope) assays. Compared to the gold-standard celloidin workflow, our method reduces processing time and costs by approximately 90% while integrating equivalent histomorphology with advanced molecular assays, providing a new benchmark for multidimensional studies in human hearing and balance pathologies.

pathology↗

bioRxiv2025

SARS-CoV-2 infection of the brain: the K18-hACE2 mouse model to illustrate the role and response of the vasculature in neurotropic viral infection

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) primarily affects the respiratory tract and lungs; however, the associated disease, coronavirus disease 2019 (COVID-19), can involve the central nervous system (CNS) in both its acute and long-term (Long COVID) clinical manifestation. The pathomechanisms underlying neurological impairments in COVID-19 are not yet fully understood, hence experimental studies to clarify the direct effect of SARS-CoV-2 in the brain can provide further insight. In the present study we used the K18-hACE2 model, intranasally challenged with SARS-CoV-2 ancestral and Delta isolates at low or medium doses, to address the hypothesis that the inflammatory response raised in the brain of infected mice is secondary to neuronal infection. Our data confirmed that the virus reaches the brain even after low dose (102 PFU/mouse, Delta isolate) infection where it targets the neurons without overt neuropathic effect, sparing the blood vessels. In situ investigation of the resulting inflammatory response showed the recruitment of leukocytes via postcapillary venules, with their accumulation in the perivascular space and occasional migration into the neuroparenchyma, without targeting and/or damage to the vessel wall. These changes were reflected in the brain transcriptome and proteome which showed positive enrichment of pathways and up-regulation of genes involved in the inflammatory response including the recruitment (including adhesion and migration) and activity of leukocytes. Additionally, morphological and transcriptome/proteome changes suggest minimal associated blood-brain barrier dysfunction. The brain metabolome and lipidome showed minimal changes; these were consistent with oxidative stress and inflammatory and immune/antiviral responses. The results obtained from our model indicate that SARS-CoV-2 infection of the neurons can result in limited neuroinflammation. These data can help to understand more fully the reaction of the CNS in COVID-19 patients, and neurotropic virus infections in general.

pathology↗

bioRxiv2025

An ultra-long heavy chain bovine antibody neutralizes SARS-CoV-2 and reacts broadly with sarbecoviruses.

The ongoing threat of new SARS-CoV-2 variants and other sarbecoviruses has driven efforts to develop broadly neutralizing monoclonal antibodies (mAbs). This study used immunized cattle, known for producing antibodies with ultra-long CDRH3 domains, to generate 33 mAbs, ten of which had ultra-long CDRH3s (>50 amino acids). Of these, mAbs P7 and 99, demonstrated broad and potent neutralization. Notably, mAb P7 neutralized all tested variants, including SARS-CoV-1, with IC50 values between 0.05 and 9.2 {micro}g/mL, and showed cross-reactivity with RBDs from various sarbecoviruses. Structural analysis revealed that mAb 99 binds the spike proteins RBD at the ACE2 binding site. Although the exact binding of P7 wasnt resolved, evidence suggests it targets a hidden epitope, promoting spike trimer dissociation via its extended CDRH3. In Syrian hamsters, both mAbs significantly reduced lung viral loads. These results support the potential of bovine-derived mAbs, particularly those with ultra-long CDRH3s, for future antiviral therapies.

immunology↗

bioRxiv2024

Unveiling a unique macrophage population in exocrine glands sustained by ILC2-derived GM-CSF

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has a non-redundant role in the emergence and maintenance of alveolar macrophages (AMs). However, its role in developmental and steady-state myelopoiesis outside the lung is largely unexplored. Scanning through developing tissues using a Fate-map and reporter of GM-CSF mouse strain, we discovered that GM-CSF was produced by type 2 innate lymphoid cells (ILC2s) in the submandibular and sublingual salivary gland (SG) during postnatal development. GM-CSF producing ILC2s foster the development of a hitherto undescribed phagocyte subset, which we named adenophages. Detailed analysis focusing on phenotypic and transcriptional profiling revealed that adenophages display shared aspects of both, macrophages and dendritic cells (DCs). We found them to be homogenously distributed across the SG, but always in close proximity to GM-CSF producing ILC2s and myoepithelial cells. Importantly, adenophages were present throughout all analyzed exocrine glands such as lacrimal glands and mammary glands, and were also identified in human SG sections, indicating a conserved role in exocrine glands across species.

immunology↗

bioRxiv2024

Multifocal cutaneous neoplastic vascular proliferations in a rainbow boa (Epicrates cenchria) collection with boid inclusion body disease

Reports on neoplastic processes in snakes are sparse regardless of their location, origin or behavior. Here, we describe the occurrence of multifocal cutaneous neoplastic processes consistent with hemangioma and hemangioendothelioma, with a differential diagnosis of angiomatosis, in a colony of native Brazilian rainbow boas (Epicrates cenchria) which also included animals affected by boid inclusion body disease (BIBD). Thirteen snakes were affected; seven of these had been introduced from other Brazilian sites years earlier, the others had been bred in house but were not offspring of knowingly affected animals. The breeding regime allowed contact between all female and male animals over the years. The cutaneous lesions were first observed over eight years ago, with additional cases detected during the three following years, but no new cases in the last five years. Two affected animals were subjected to a post mortem examination and were found to suffer from peliosis hepatis as one of the additional pathological changes. BIBD was confirmed in five of the eight examined animals, by histology, immunohistology for reptarenavirus nucleoprotein, and multiplex RT-PCR targeting the reptarenavirus S segment. Reptarenavirus infection was also detected in cells in the cutaneous neoplastic processes. PCRs for Bartonella henselae and B. quintana as well as bacterial DNA in general, performed on a pool of six skin lesions, yielded negative results, ruling out ongoing bacterial infection, like bacillary angiomatosis in humans, of the lesions. The results hint towards an association of reptarenavirus infection and BIBD with neoplastic processes which is worth further investigations.

pathology↗

bioRxiv2024

The golden Syrian hamster (Mesocricetus auratus) as a model to decipher relevant pathogenic aspects of sheep-associated malignant catarrhal fever

Malignant catarrhal fever (MCF) is an often fatal sporadic gammaherpesvirus-induced disease of ruminants with global relevance. Ovine gammaherpesvirus-2 (OvHV-2), with sheep as reservoir host, is a major cause of MCF in susceptible species. Despite extensive research on the molecular aspects of the disease, its pathogenesis is not yet fully understood. The present study re-established the Syrian golden hamster (Mesocricetus auratus) as amenable animal model of MCF and applied complementary in situ approaches to confirm recent findings in natural disease that could shed new light on pathogenetic aspects of MCF. These showed that systemic OvHV-2 infection is associated with T cell and macrophage dominated mononuclear infiltrates and vasculitis in various organs. Both T cells and monocytes/macrophages harbor the virus, and infected leukocytes are abundant in the infiltrates. The results also indicate that OvHV-2 has a broader target cell spectrum, including vascular endothelial cells and selected squamous epithelia. The former supports the interpretation that the inflammatory processes develop due to circulating activated, infected T cells and monocytes that home to tissues and emigrate from vessels prone to leukocyte emigration, possibly with direct interaction between virus infected leukocytes and endothelial cells. The latter supports the hypothesis of a graft versus host disease scenario, without viral cytopathic effect on epithelial cells but infiltration of the mucosa by infected T cells and macrophages. The disease processes are accompanied by evidence of expansion of the T cell compartments and the monocyte/macrophage pool in lymphatic tissues and bone marrow.

pathology↗

bioRxiv2024

Haemolymphatic tissues of captive boa constrictor (Boa constrictor): morphological features in healthy individuals and with Boid Inclusion Body Disease

Knowledge on the structure and composition of the haematopoietic tissue (HT) is essential to understand the basic immune functions of the immune system in any species. For reptiles, it is extremely limited, hence we undertook an in-depth in situ investigation of the HT (bone marrow, thymus, spleen, lymphatic tissue of the alimentary tract) in the common boa (Boa constrictor). We also assessed age- and disease-related changes, with a special focus on Boid Inclusion Body Disease, a highly relevant reptarenavirus-associated disease in boid snakes. The HT was subjected to gross, histological and ultrastructural examination, including special stains, immunohistochemistry, in situ hybridization and morphometric analyses. In general, the HT was dominated by T cells and lacked a clear structural organization, such as follicle formation. BIBD was associated with significantly higher cellularity and a granulomatous response in the spleen, and the presence of virus-infected haematopoietic cells in the bone marrow, suggesting the latter as a persistent source of viremia. HighlightsO_LILymphatic tissues of B. constrictor lack organization and are dominated by T cells C_LIO_LIThe thymus of B. constrictor shows slow age-related involution C_LIO_LIBIBD-positive boas show a granulomatous response in the spleen C_LIO_LIReptarenaviruses infect haematopoietic cells in the bone marrow C_LIO_LIReptarenavirus infected bone marrow cells might represent a source of viremia C_LI

pathology↗

bioRxiv2024

Phlorotannin rich Ascophyllum nodosum seaweed extract inhibits influenza infection

Seaweed derived compounds are a renewable resource utilised in the manufacturing and food industry. This study focuses on an Enriched seaweed extract (ESE) isolated from Ascophyllum nodosum. ESE was screened for antiviral activity by plaque reduction assays against influenza A viruses (IAV) H1N1 and H3N2 subtypes. Time of addition assays and FACS analysis were used to help determine the modes of action. The therapeutic potential of ESE was then explored using differentiated human bronchiole epithelial cells at the air liquid interphase and a murine model challenged with IAV. The data indicates ESE primarily interacts directly with virions, preventing virus cell binding. Interestingly, ESE also inhibits early and late stage of the influenza A lifecycle when treatment occurs after cell binding. This inhibitory effect appears to prevent internalisation of virus and release of progeny virus by targeting neuraminidase activity. Intranasal administration of ESE in mice infected with IAV reduced viral load in lung tissue. ESE may be a promising broad acting antiviral agent in the treatment of influenza infections.

microbiology↗

bioRxiv2024

Dendritic cell targeting in lymph nodes with engineered modular adapters improves HAdV5 and HC-HAdV5 tumor vaccination by co-secretion of IL-2v and IL-21

Adenoviral vectors demonstrate encouraging clinical outcomes for B- and T-cell vaccines. With such approaches, multiple payloads can be delivered, beyond the antigen itself. Nevertheless, the human adenoviral vector serotype C5 (HAdV5) exhibits limited transduction efficiency to dendritic cells (DC), therefore necessitating very high viral loads. Targeting antigen-presenting cells (APC) has remained challenging. To solve this problem, we developed a versatile platform that employs modular retargeting adapters to enhance transduction of specific cell types, including challenging host cells. By rational design, we constructed a dual-adapter for DC-SIGN and CD11c and demonstrate successful targeting of HAdV5 to human and murine DCs. Our in vivo characterization highlights improved and specific transduction of DCs in draining lymph nodes. Moreover, a tumor vaccination study showcases the advantageous co-expression of T cell stimulatory cytokines (IL-2v or IL-21) locally in lymph nodes alongside a potent tumor antigen. Lymph node-directed gene therapy at significantly reduced vector loads circumvents potential systemic toxicity of stimulating payloads. Our proposed low-dosage DC-targeted vaccine offers an effective solution for patients and also minimizes potential adenovirus-related side-effects. The robust immunogenicity of HC-HAdV5, with its large coding capacity (37 kbp DNA), opens up exciting possibilities for future therapeutic combination strategies.

biochemistry↗

bioRxiv2024

The effect of molnupiravir and nirmatrelvir on SARS-CoV-2 genome diversity in infected and immune suppressed mice

SynopsisO_ST_ABSObjectivesC_ST_ABSImmunocompromised individuals are susceptible to severe COVID-19 and potentially contribute to the emergence of variants with altered pathogenicity due to persistent infection. This study investigated the impact of immunosuppression on SARS-CoV-2 infection in k18-hACE2 mice and the effectiveness of antiviral treatments in this context during the first 7 days of infection. MethodsMice were immunosuppressed using cyclophosphamide and infected with a B daughter lineage of SARS-CoV-2. Molnupiravir and nirmatrelvir, alone and in combination, were administered and viral load and viral sequence diversity was assessed. ResultsTreatment of infected but immune compromised mice with both compounds either singly or in combination resulted in decreased viral loads and pathological changes compared to untreated animals. Treatment also abrogated infection of neuronal tissue. However, no consistent changes in the viral consensus sequence were observed, except for the emergence of the S:H655Y mutation. Molnupiravir, but not nirmatrelvir or immunosuppression alone, increased the transition/transversion (Ts/Tv) ratio, representative of G>A and C>U mutations and this increase was not altered by the co-administration of nirmatrelvir with molnupiravir. Notably, immunosuppression itself did not appear to promote the emergence of mutational characteristic of variants of concern (VOCs). ConclusionsFurther investigations are warranted to fully understand the role of immunocompromised individuals in VOC development, especially by taking persistence into consideration, and to inform optimised public health strategies. It is more likely that immunodeficiency promotes viral persistence but does not necessarily lead to substantial consensus-level changes in the absence of antiviral selection pressure. Consistent with mechanisms of action, molnupiravir showed a stronger mutagenic effect than nirmatrelvir in this model.

pharmacology and toxicology↗