Biology subjects

Moore, K. M.

Publications and source records attributed to Moore, K. M..

6 recordsLinked to original sources

bioRxiv2026

Light Chain Dominant Quaternary Epitope Recognition and IgG3 Switching Drive Broad Dengue and Zika Virus Neutralization

Defining how antibodies achieve broad neutralization across antigenically related flaviviruses is essential for rational therapeutics and vaccine design. Here, we describe 3A06, a human monoclonal antibody that neutralizes dengue virus (DENV) serotypes 1-3 and zika virus (ZIKV). Notably, subclass switching to IgG3 exhibits expanded neutralizing activity against all four DENV serotypes. High-resolution cryo-electron microscopy (cryo-EM) analysis of 3A06 Fab bound to chimeric ZIKV virions shows that 3A06 engages a quaternary epitope spanning three E protomers. Functional analyses identify a major functional contribution from the light-chain, where somatic hypermutations are critical for neutralization potency, and reversion of improbable mutations substantially reduces neutralization and increases antibody dependent enhancement (ADE) at sub-neutralizing concentrations. Cryo-EM analyses of intact IgG3 in complex with chimeric DENV2 and DENV4 show that the conformational clexibility and extended IgG3 Fc-hinge enable bivalent engagement across E-protein rafts in multiple concigurations, overcoming geometrical constraints that limit binding in the IgG1 format. Together, these results define a distinct mode of epitope recognition relative to previously characterized E-dimer epitope (EDE)-specific broadly neutralizing antibodies (bnAbs), and demonstrate how IgG3 subclass architecture can expand virus neutralization breadth. These insights inform the rational engineering of antibodies and vaccines targeting quaternary epitopes on flaviviruses to overcome viral diversity.

immunology↗

bioRxiv2025

FcγRI is the key determinant of antibody-mediated Zika virus infection of human placental macrophages

Zika virus (ZIKV) can be vertically transmitted from a pregnant mother to the developing fetus, resulting in microcephaly and/or other congenital malformations. Dengue virus (DENV) cross-reactive antibodies can facilitate ZIKV placental transcytosis and enhance ZIKV infection of placenta macrophage-Hofbauer cells through binding to Fc-{gamma} receptors (Fc{gamma}Rs). To understand the role of individual Fc{gamma}R in antibody-mediated ZIKV placental infection, we generated a comprehensive panel of Fc-variants spanning a wide range of binding affinities to different Fc{gamma}Rs. We found that mutations with increased affinity to Fc{gamma}RI strongly correlated with an increased frequency of infected pro-monocytic U937 and Hofbauer cells. Next, we genetically deleted individual Fc{gamma}R in U937 cells, and found that the knockout of FCGR1A gene completely abolished ZIKV infection. In contrast, the deletion of FCGR2B gene showed no effect on ZIKV infection, and the deletion of FCGR2A gene had only a moderate impact on ZIKV infection. We further observed that Fc{gamma}RI was involved in both increased ZIKV internalization and replication. Collectively, our results establish Fc{gamma}RI as the key Fc receptor responsible for antibody-mediated ZIKV infection in both U937 and primary placental macrophages. These mechanistic findings not only provide insight into the importance of Fc{gamma}RI in ZIKV vertical transmission but also highlight Fc{gamma}RI as a potential therapeutic target, with significant implications for the development of strategies to prevent ZIKV transmission from mother to fetus.

immunology↗

bioRxiv2024

Eosinophils protect against SARS-CoV-2 following a vaccine breakthrough infection

Waning immunity and the emergence of immune evasive SARS-CoV-2 variants jeopardize vaccine efficacy leading to breakthrough infections. We have previously shown that innate immune cells play a critical role in controlling SARS-CoV-2. To investigate the innate immune response during breakthrough infections, we modeled breakthrough infections by challenging low-dose vaccinated mice with a vaccine-mismatched SARS-CoV-2 Beta variant. We found that low-dose vaccinated infected mice had a 2-log reduction in lung viral burden, but increased immune cell infiltration in the lung parenchyma, characterized by monocytes, monocyte-derived macrophages, and eosinophils. Single cell RNA-seq revealed viral RNA was highly associated with eosinophils that corresponded to a unique IFN-{gamma} biased signature. Antibody-mediated depletion of eosinophils in vaccinated mice resulted in increased virus replication and dissemination in the lungs, demonstrating that eosinophils in the lungs are protective during SARS-CoV-2 breakthrough infections. These results highlight the critical role for the innate immune response in vaccine mediated protection against SARS-CoV-2.

immunology↗

bioRxiv2024

Single cell analysis reveals an antiviral network that controls Zika virus infection in human dendritic cells

Zika virus (ZIKV) is a mosquito-borne flavivirus that caused an epidemic in the Americas in 2016 and is linked to severe neonatal birth defects, including microcephaly and spontaneous abortion. To better understand the host response to ZIKV infection, we adapted the 10x Genomics Chromium single cell RNA sequencing (scRNA-seq) assay to simultaneously capture viral RNA and host mRNA. Using this assay, we profiled the antiviral landscape in a population of human moDCs infected with ZIKV at the single cell level. The bystander cells, which lacked detectable viral RNA, expressed an antiviral state that was enriched for genes coinciding predominantly with a type I interferon (IFN) response. Within the infected cells, viral RNA negatively correlated with type I IFN dependent and independent genes (antiviral module). We modeled the ZIKV specific antiviral state at the protein level leveraging experimentally derived protein-interaction data. We identified a highly interconnected network between the antiviral module and other host proteins. In this work, we propose a new paradigm for evaluating the antiviral response to a specific virus, combining an unbiased list of genes that highly correlate with viral RNA on a per cell basis with experimental protein interaction data. Our ZIKV-inclusive scRNA-seq assay will serve as a useful tool to gaining greater insight into the host response to ZIKV and can be applied more broadly to the flavivirus field.

microbiology↗

bioRxiv2021

mRNA-1273 and BNT162b2 mRNA vaccines have reduced neutralizing activity against the SARS-CoV-2 Omicron variant

The BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) vaccines generate potent neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the global emergence of SARS-CoV-2 variants with mutations in the spike protein, the principal antigenic target of these vaccines, has raised concerns over the neutralizing activity of vaccine-induced antibody responses. The Omicron variant, which emerged in November 2021, consists of over 30 mutations within the spike protein. Here, we used an authentic live virus neutralization assay to examine the neutralizing activity of the SARS-CoV-2 Omicron variant against mRNA vaccine-induced antibody responses. Following the 2nd dose, we observed a 30-fold reduction in neutralizing activity against the omicron variant. Through six months after the 2nd dose, none of the sera from naive vaccinated subjects showed neutralizing activity against the Omicron variant. In contrast, recovered vaccinated individuals showed a 22-fold reduction with more than half of the subjects retaining neutralizing antibody responses. Following a booster shot (3rd dose), we observed a 14-fold reduction in neutralizing activity against the omicron variant and over 90% of boosted subjects showed neutralizing activity against the omicron variant. These findings show that a 3rd dose is required to provide robust neutralizing antibody responses against the Omicron variant.

immunology↗

bioRxiv2018

Integrin αVβ6-EGFR crosstalk regulates bidirectional force transmission and controls breast cancer invasion

The mechanical properties of the extracellular matrix within tumours control multiple cellular functions that drive cancer invasion and metastasis. However, the mechanisms controlling microenvironmental force sensation and transmission, and how these regulate transcriptional reprogramming and invasion, are unclear. Our aim was to understand how mechanical inputs are transmitted bidirectionally and translated into biochemical and transcriptional outputs to drive breast cancer progression. We reveal that adhesion receptor and growth factor receptor crosstalk regulates a bidirectional feedback mechanism co-ordinating force-dependent transcriptional regulation and invasion.\n\nIntegrin V{beta}6 drives invasion in a range of carcinomas and is a potential therapeutic target. V{beta}6 exhibits unique biophysical properties that promote force-generation and increase matrix rigidity. We employed an inter-disciplinary approach incorporating proteomics, biophysical techniques and multi-modal live-cell imaging to dissect the role of V{beta}6-EGFR crosstalk on transmission of mechanical signals bidirectionally between the extracellular matrix and nucleus.\n\nWe show that V{beta}6 expression correlates with poor prognosis in triple-negative breast cancer (TNBC) and drives invasion of TNBC cells. Moreover, our data show that a complex regulatory mechanism exists involving crosstalk between V{beta}6 integrin and EGFR that impacts matrix stiffness, force transmission to the nucleus, transcriptional reprogramming and microenvironment rigidity. V{beta}6 engagement triggers EGFR & MAPK signalling and V{beta}6-EGFR crosstalk regulates mutual receptor trafficking mechanisms. Consequently, EGF stimulation suppresses V{beta}6-mediated force-application on the matrix and nuclear shuttling of force-dependent transcriptional co-activators YAP/TAZ. Finally, we show that crosstalk between V{beta}6 & EGFR regulates TNBC invasion.\n\nWe propose a model whereby V{beta}6-EGFR crosstalk regulates matrix stiffening, but also the transmission of extracellular forces into the cell in order to co-ordinate transcriptional reprogramming and invasion. To exploit adhesion receptors and receptor tyrosine kinases therapeutically, it will be essential to understand the integration of their signalling functions and how crosstalk mechanisms influence invasion and the response of tumours to molecular therapeutics.

cancer biology↗