Biology subjects

Christie-Holmes, N.

Publications and source records attributed to Christie-Holmes, N..

3 recordsLinked to original sources

bioRxiv2022

Antibody avidity and multi-specificity combined to confer protection against SARS-CoV-2 and resilience against viral escape

SARS-CoV-2, the causative agent of COVID-19, has been responsible for a global pandemic. Monoclonal antibodies have been used as antiviral therapeutics, but have been limited in efficacy by viral sequence variability in emerging variants of concern (VOCs), and in deployment by the need for high doses. In this study, we leverage the MULTI-specific, multi-Affinity antiBODY (Multabody, MB) platform, derived from the human apoferritin protomer, to drive the multimerization of antibody fragments and generate exceptionally potent and broad SARS-CoV-2 neutralizers. CryoEM revealed a high degree of homogeneity for the core of these engineered antibody-like molecules at 2.1 [A] resolution. We demonstrate that neutralization potency improvements of the MB over corresponding IgGs translates into superior in vivo protection: in the SARS-CoV-2 mouse challenge model, comparable in vivo protection was achieved for the MB delivered at 30x lower dose compared to the corresponding IgGs. Furthermore, we show how MBs potently neutralize SARS-CoV-2 VOCs by leveraging augmented avidity, even when corresponding IgGs lose their ability to neutralize potently. Multiple mAb specificities could also be combined into a single MB molecule to expand the neutralization breadth beyond SARS-CoV-2 to other sarbecoviruses. Our work demonstrates how avidity and multi-specificity combined can be leveraged to confer protection and resilience against viral diversity that exceeds that of traditional monoclonal antibody therapies.

immunology↗

bioRxiv2021

Systematic genome-scale identification of host factors for SARS-CoV-2 infection across models yields a core single gene dependency; ACE2

SARS-CoV-2, depends on host cell components for replication, therefore the identification of virus-host dependencies offers an effective way to elucidate mechanisms involved in viral infection. Such host factors may be necessary for infection and replication of SARS-CoV-2 and, if druggable, presents an attractive strategy for anti-viral therapy. We performed genome wide CRISPR knockout screens in Vero E6 cells and 4 human cell lines including Calu-3, Caco-2, Hek293 and Huh7 to identify genetic regulators of SARS-CoV-2 infection. Our findings identified only ACE2, the cognate SARS-CoV-2 entry receptor, as a common host dependency factor across all cell lines, while all other host genes identified were cell line specific including known factors TMPRSS2 and CTSL. Several of the discovered host-dependency factors converged on pathways involved in cell signalling, lipid metabolism, immune pathways and chromatin modulation. Notably, chromatin modulator genes KMT2C and KDM6A in Calu-3 cells had the strongest impact in preventing SARS-CoV-2 infection when perturbed. Overall, the network of host factors that have been identified will be broadly applicable to understanding the impact of SARS-CoV-2 on human cells and facilitate the development of host-directed therapies. IN BRIEFSARS-CoV-2, depends on host cell components for infection and replication. Genome-wide CRISPR screens were performed in multiple human cell lines to elucidate common host dependencies required for SARS-CoV-2 infection. Only ACE2, the cognate SARS-CoV-2 entry receptor, was common amongst cell lines, while all other host genes identified were cell line specific, several of which converged on pathways involved in cell signalling, lipid metabolism, immune pathways, and chromatin modulation. Overall, a network of host factors was identified that will be broadly applicable to understanding the impact of SARS-CoV-2 on human cells and facilitate productive targeting of host genes and pathways. HIGHLIGHTS- Genome-wide CRISPR screens for SARS-CoV-2 in multiple human cell lines - Identification of wide-ranging cell-type dependent genetic dependencies for SARS-CoV-2 infection - ACE2 is the only common host factor identified across different cell types

systems biology↗

bioRxiv2020

Multivalency transforms SARS-CoV-2 antibodies into broad and ultrapotent neutralizers

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes Coronavirus Disease 2019 (COVID-19), has caused a global pandemic. Antibodies are powerful biotherapeutics to fight viral infections; however, discovery of the most potent and broadly acting clones can be lengthy. Here, we used the human apoferritin protomer as a modular subunit to drive oligomerization of antibody fragments and transform antibodies targeting SARS-CoV-2 into exceptionally potent neutralizers. Using this platform, half-maximal inhibitory concentration (IC50) values as low as 9 x 10-14 M were achieved as a result of up to 10,000-fold potency enhancements. Combination of three different antibody specificities and the fragment crystallizable (Fc) domain on a single multivalent molecule conferred the ability to overcome viral sequence variability together with outstanding potency and Ig-like in vivo bioavailability. This MULTi-specific, multi-Affinity antiBODY (Multabody; or MB) platform contributes a new class of medical countermeasures against COVID-19 and an efficient approach to rapidly deploy potent and broadly-acting therapeutics against infectious diseases of global health importance. One Sentence Summarymultimerization platform transforms antibodies emerging from discovery screens into potent neutralizers that can overcome SARS-CoV-2 sequence diversity.

molecular biology↗