Biology subjects

Daniel, K.

Publications and source records attributed to Daniel, K..

8 recordsLinked to original sources

bioRxiv2026

Antibody evasion and receptor binding of SARS-CoV-2 RW.1.1

The continued evolution of SARS-CoV-2 is shaped by changes in antibody evasion and receptor engagement that influence viral fitness. RW.1.1, an emerging descendant of XFJ carrying five additional spike substitutions, has recently increased in frequency in North America. Here, we characterized the serum antibody evasion, monoclonal antibody sensitivity, and ACE2 receptor engagement of RW.1.1. Pseudovirus neutralization assays using sera from adults showed that RW.1.1 was not more resistant to serum neutralization than currently circulating variants, with neutralizing titers comparable to XFG, BA.3.2.2, and NB.1.8.1 in the tested cohort. Neutralization of RW.1.1 also did not differ significantly among adults, children, and infants and toddlers. Despite the absence of increased overall serum antibody resistance, monoclonal antibody neutralization assays revealed substantial resistance to several RBD class 1 antibodies and increased resistance to a subset of class 1/4 antibodies. Moreover, RW.1.1 exhibited reduced ACE2 receptor engagement compared with XFG, which itself has reduced receptor engagement relative to earlier JN.1 subvariants. Thus, RW.1.1 has continued to expand despite a further reduction in receptor engagement and without a substantial increase in overall serum antibody evasion. These findings suggest that the fitness of emerging SARS-CoV-2 variants may depend not only on the magnitude of antibody evasion but also on the specific components of the polyclonal antibody response that are evaded, highlighting the increasingly complex interplay between population immunity and receptor engagement in shaping SARS-CoV-2 evolution.

microbiology↗

bioRxiv2026

SARS-CoV-2 BA.3.2.2 is more evasive of neutralization by sera from young children

Dominant SARS-CoV-2 variants have most prominently displayed greater evasion of serum neutralizing antibodies than predecessor strains. BA.3.2, a descendant of Omicron BA.3, carrying 43 additional spike mutations, emerged in 2024, and over the last several months its subvariant BA.3.2.2 has slowly increased in prevalence globally. BA.3.2.2 continues to circulate at lower frequency than the genetically and antigenically distant dominant JN.1 subvariants NB.1.8.1 and XFG. However, concerningly, epidemiologic analyses have suggested that a larger proportion of COVID-19 cases in children are caused by BA.3.2.2 compared to adults, raising the possibility that susceptibility to BA.3.2.2 differs across age groups. Since immune imprinting shapes variant-specific anti-SARS-CoV-2 antibody profiles and children born after 2021 primarily were first exposed to Omicron subvariants, we hypothesized that young children may have lower circulating neutralizing antibody titers against BA.3.2.2 than adults. Using pseudovirus neutralization assays, we measured titers against BA.3.2.2 and other SARS-CoV-2 variants in serum or plasma samples from a total of 36 adults ([≥]18 years old), school-age children (3-10 years old), and infants/toddlers (6-28 months old) in the US. We found that both cohorts of children had lower geometric mean titers against BA.3.2.2 than adults, even though all tested age groups had similar titers against dominant strains NB.1.8.1 and XFG. Together, these findings suggest that susceptibility to emerging SARS-CoV-2 variants may diverge across age groups, perhaps as a result of their different exposure histories. Furthermore, these results highlight the importance of SARS-CoV-2 surveillance and the monitoring of immunity against viral variants across age ranges.

microbiology↗

bioRxiv2026

VYD2311 is a promising candidate for passive immunization against COVID-19 in immunocompromised individuals

For millions of immunocompromised individuals, vaccines may not elicit adequate protection from infections, so alternative strategies for pre-exposure prophylaxis are essential. There is only one non-vaccine product authorized in the U.S. as pre-exposure prophylaxis against COVID-19: the monoclonal antibody pemivibart. We previously showed that pemivibart had lower neutralizing activity in vitro against many recent dominant SARS-CoV-2 variants, such as KP.3.1.1, NB.1.8.1, and LP.8.1.1, than it had against JN.1, which was dominant when the antibody was first authorized. The manufacturer of pemivibart (Invivyd) recently initated clinical testing of a new monoclonal antibody derived from pemivibart, VYD2311, but there are no available studies of the activity of VYD2311 against dominant and emerging SARS-CoV-2 variants. Here, using pseudovirus neutralization assays, we measured the neutralizing activity of laboratory-synthesized VYD2311 and pemivibart against dominant and emerging SARS-CoV-2 variants, including XFG, NB.1.8.1, and the genetically distant BA.3.2.2. We found that VYD2311 potently neutralized all tested variants in vitro, dramatically more so than pemivibart. Combined with interpretation of earlier clinical trials of a parental antibody product, we conclude that VYD2311 is a promising candidate for passive immunoprophylaxis against COVID-19, particularly for those who do not respond well to vaccination.

microbiology↗

bioRxiv2026

Development of a multi-species luciferase-based double antigen ELISA for the detection of antibodies against Influenza A virus H5 clade 2.3.4.4b

The highly pathogenic avian influenza viruses (HPAIV) of subtype H5N1 represent a major threat to animal and public health. The current panzootic with H5 clade 2.3.4.4b has caused numerous, widespread outbreaks in various domestic and wild avian species with high mortalities, massive losses and a high frequency of spillover events to unexpected novel mammalian hosts such as dairy cows. The global H5N1 situation raises serious concerns about zoonotic risks due to effective mammal-to-mammal transmission. Therefore, it is critical to increase surveillance intensity of a broadened species range, particularly at the human-animal interface. For this purpose, reliable and cost-effective serological tools that are easy to perform and suitable for high-throughput screenings are critically needed. The newly developed double antigen ELISA format employing a luminescence-based detection technology has demonstrated to comply with such prerequisites. The assay allowed the detection of H5-specific antibodies even early after infection or vaccination in a wide range of birds and mammals including humans. It further demonstrated superior analytical sensitivity and high specificity for antibodies directed against H5 hemagglutinin of clade 2.3.4.4b as no cross-reactivity with other hemagglutinin subtypes was observed. Thus, the assay represents a valuable contribution to existing serological diagnostic tests for a clade-optimized detection of influenza A virus antibodies in a broad range of species. ImportanceThe ongoing HPAIV H5N1 panzootic has caused numerous outbreaks in domestic and wild animals with frequent spillover events to unexpected host species, which underscores the importance of an intensified surveillance. However, sensitive and specific multi-species serological assays represent a major gap. For this purpose, we developed a novel double antigen ELISA which employs an innovative luminescence-based read-out strategy. The test allowed a highly sensitive and specific detection of H5-specific antibodies even early after infection or vaccination in a wide range of avian and mammalian species including humans. It therefore represents a significant contribution to improving species-independent serological diagnostic tools for the detection of influenza A virus antibodies.

microbiology↗

bioRxiv2025

Detection of low pre-existing humoral immunity against influenza virus H5N1 clade 2.3.4.4b in unexposed individuals

The spill-over of Influenza A virus H5N1 clade 2.3.4.4b from cattle to humans highlights the risk of a human H5N1 pandemic. Given the impact of pre-existing immunity on the course and severity of viral infections, we comprehensively assessed the humoral immunity against the H5N1 A/Texas/37/2024 isolate in H5N1-naive individuals. To this end, we performed complementary binding and neutralization assays on 66 subjects and ranked activities among a panel of 76 influenza A virus isolates. We detected low but distinct cross-neutralizing titers against A/Texas/37/2024 with a 3.9 to 15.6-fold reduction compared to selected H1N1 or H3N2 strains. By cloning and evaluating 136 monoclonal antibodies from memory B cells, we identified potent A/Texas/37/2024-neutralizing monoclonal antibodies in five out of six investigated individuals. These antibodies cross-neutralize H1, compete with antibodies targeting the HA stem, and protect mice from lethal H5N1 challenge. Our findings demonstrate partial pre-existing humoral immunity to A/Texas/37/2024 in H5N1-naive individuals.

immunology↗

bioRxiv2024

Scoping Review of Maternal Monocytes and the Syncytiotrophoblast: Bi-Directional Communication in the Intervillous Space

The relationship between maternal monocytes and the placenta is crucial for successful pregnancy. As existing reviews focus on the research on decidual macrophages or Hofbauer cells (fetal macrophages), we conducted a scoping review of literature studies examining the relationship between circulating maternal monocytes and the villous trophoblast. The goal of this review was to outline existing research within the field, disseminate further information, and to identify current knowledge gaps within the field. We searched the PubMed (MEDLINE) database for relevant articles published since 1995 that studied human tissue or cell lines. Our results showed clear trends in the type of monocyte and placental primary tissues and cell lines used. Further classification of these articles revealed four primary categories of monocyte-trophoblast interaction research: monocyte presence or recruitment to the placenta, monocyte phenotype in the intervillous space, monocyte-placental adhesion, and monocyte interaction with syncytiotrophoblast-derived extracellular vesicles (STBEVs). Although limited in scope and number, these studies implicate the importance of monocyte-trophoblast interactions, and their significant roles in maternal disease.

immunology↗

bioRxiv2022

Glycolytic interference blocks influenza A virus propagation by impairing viral polymerase-driven synthesis of genomic vRNA

Influenza A virus (IAV), like any other virus, provokes considerable modifications of its host cells metabolism. This includes a substantial increase in the uptake as well as the metabolization of glucose. Although it is known for quite some time that suppression of glucose metabolism restricts virus replication, the exact molecular impact on the viral life cycle remained enigmatic so far. Using 2-deoxy-D-glucose (2-DG) we examined how well inhibition of glycolysis is tolerated by host cells and which step of the IAV life cycle is affected. We observed that effects induced by 2-DG are reversible and that cells can cope with relatively high concentrations of the inhibitor by compensating the loss of glycolytic activity by upregulating other metabolic pathways. Moreover, mass spectrometry data provided information on various metabolic modifications induced by either the virus or agents interfering with glycolysis. In the presence of 2-DG viral titers were significantly reduced in a dose-dependent manner. The supplementation of direct or indirect glycolysis metabolites led to a partial or almost complete reversion of the inhibitory effect of 2-DG on viral growth and demonstrated that indeed the inhibition of glycolysis and not of N-linked glycosylation was responsible for the observed phenotype. Importantly, we could show via conventional and strand-specific qPCR that the treatment with 2-DG led to a prolonged phase of viral mRNA synthesis while the accumulation of genomic vRNA was strongly reduced. At the same time, minigenome assays showed no signs of a general reduction of replicative capacity of the viral polymerase. Therefore, our data suggest that the significant reduction in IAV replication by glycolytic interference occurs mainly due to an impairment of the dynamic regulation of the viral polymerase which conveys the transition of the enzymes function from transcription to replication. Author SummaryUpon infection the influenza A virus alters the metabolism of infected cells. Among others, this includes a pronounced increase in glucose metabolism. We aimed to get a better understanding of these metabolic virus-host interactions and to unravel the mechanism by which glycolytic inhibition impairs the viral life cycle. On the one hand, we observed a virus-induced upregulation of many glycolysis metabolites which could often be reversed by the administration of a glycolysis inhibitor. On the other hand, our data suggested that the inhibitor treatment severely impaired viral propagation by interfering with the regulation of the viral polymerase. This manifested in an extended phase of transcription, while replication was strongly reduced. Additionally, we assessed the safety and tolerability of the used drug in immortalized and primary cells. Our study sheds more light on metabolic virus-host interactions and provides a better understanding of metabolic interference as a potential host-targeted antiviral approach, which does not bear the risk of creating resistances.

microbiology↗

bioRxiv2018

Conditional control of fluorescent protein degradation by an auxin-dependent nanobody

The conditional and reversible depletion of proteins by auxin-mediated degradation is a powerful tool to investigate protein functions in cells and whole organisms. However, its wider applications require fusing the auxin-inducible degron (AID) to individual target proteins. Thus, establishing the auxin system for multiple proteins can be challenging. Another approach for directed protein degradation are anti-GFP nanobodies, which can be applied to GFP stock collections that are readily available in different experimental models. Here, we combine the advantages of auxin and nanobody-based degradation technologies creating an AID-nanobody to degrade GFP-tagged proteins at different cellular structures in a conditional and reversible manner in human cells. We demonstrate efficient and reversible inactivation of the anaphase promoting complex/cyclosome (APC/C) and thus provide new means to study the functions of this essential ubiquitin E3 ligase. Further, we establish auxin degradation in a vertebrate model organism by employing AID-nanobodies in zebrafish.

cell biology↗