Biology subjects

Gervais, C.

Publications and source records attributed to Gervais, C..

4 recordsLinked to original sources

bioRxiv2024

A new spatial multi-omics approach to deeply characterize human cancer tissue using a single tissue section

In the ever-changing world of digital pathology, being able to extract a maximum amount of information from a patient tissue sample is of paramount importance for better diagnosis, disease characterization, and therapeutic strategies. Recent technologies such as multiplex immunofluorescence imaging and spatial transcriptomic now enable a deep analysis of protein and gene expression while retaining the spatial context of the tissue. Here, we describe an innovative approach combining a 34-protein Phenocycler panel and transcriptome analysis using Visium on a single head and neck squamous cell carcinoma section. While protein analysis reveals the complexity of the immune phenotypes involved in the disease, transcriptome analysis reveals the intricate cellular states of cancer cells that coexist within the patients tumor. Finally, integrating both omics modalities, we uncover unique comparison of gene and protein expression of spatially resolved cellular subspaces.

cancer biology↗

bioRxiv2021

Arsenal of Nanobodies for Broad-Spectrum Countermeasures against Current and Future SARS-CoV-2 Variants of Concerns

Nanobodies offer several potential advantages over mAbs for the control of SARS-CoV-2. Their ability to access cryptic epitopes conserved across SARS-CoV-2 variants of concern (VoCs) and feasibility to engineer modular, multimeric designs, make these antibody fragments ideal candidates for developing broad-spectrum therapeutics against current and continually emerging SARS-CoV-2 VoCs. Here we describe a diverse collection of 37 anti-SARS-CoV-2 spike glycoprotein nanobodies extensively characterized as both monovalent and IgG Fc-fused bivalent modalities. The panel of nanobodies were shown to have high intrinsic affinity; high thermal, thermodynamic and aerosolization stability; broad subunit/domain specificity and cross-reactivity across many VoCs; wide-ranging epitopic and mechanistic diversity; high and broad in vitro neutralization potencies; and high neutralization efficacies in hamster models of SARS-CoV-2 infection, reducing viral burden by up to six orders of magnitude to below detectable levels. In vivo protection was demonstrated with anti-RBD and previously unreported anti-NTD and anti-S2 nanobodies. This collection of nanobodies provides a therapeutic toolbox from which various cocktails or multi-paratopic formats could be built to tackle current and future SARS-CoV-2 variants and SARS-related viruses. Furthermore, the high aerosol-ability of nanobodies provides the option for effective needle-free delivery through inhalation.

bioengineering↗

bioRxiv2020

Rapid, high-yield production of full-length SARS-CoV-2 spike ectodomain by transient gene expression in CHO cells

Recombinant forms of the spike protein of SARS-CoV-2 and related viruses have proven difficult to produce with good yields in mammalian cells. Given the panoply of potential COVID-19 diagnostic tools and therapeutic candidates that require purified spike protein and its importance for ongoing SARS-CoV-2 research, we have explored new approaches for spike production and purification. Three transient gene expression methods based on PEI-mediated transfection of CHO or HEK293 cells in suspension culture in chemically-defined media were compared for rapid production of full-length SARS-CoV-2 ectodomain. A high-cell-density protocol using DXB11-derived CHOBRI/rcTA cells gave substantially better yields than the other methods. Different forms of the spike were expressed, including the wild-type SARS-CoV-2 sequence and a mutated/stabilized form (to favor expression of the full-length spike in prefusion conformation), with and without fusion to putative trimerization domains. An efficient two-step affinity purification method was also developed. Ultimately, we have been able to produce highly homogenous preparations of full-length spike, both monomeric and trimeric, with yields of 100-150 mg/L. The speed and productivity of this method support further development of CHO-based approaches for recombinant spike protein manufacturing.

bioengineering↗

bioRxiv2020

CAR T cell entry into tumor islets is a two-step process dependent on IFNγ and ICAM-1

Adoptive transfer of T cells expressing chimeric antigen receptors (CARs) has shown remarkable clinical efficacy against advanced B cell malignancies but not yet against solid tumors. Here, we used fluorescent imaging microscopy and ex vivo assays to compare the early functional responses (migration, Ca2+ and cytotoxicity) of CD20 and EGFR CAR T cells upon contact with malignant B and carcinoma cells. Our results indicate that CD20 CAR T cells rapidly form productive ICAM-1-dependent conjugates with their targets. By comparison, EGFR CAR T cells only interact at first with a subset of carcinoma cells located at the periphery of tumor islets. After this initial peripheral activation, EGFR CAR T cells progressively infiltrate the center of tumor cell regions. The analysis of this two-step entry process shows that activated CAR T cells trigger the upregulation of ICAM-1 on tumor cells in an IFN{gamma}-dependent pathway. The blockade of ICAM-1/LFA-1 interactions prevents CAR T cell recruitment into tumor islets. The requirement for IFN{gamma} and ICAM-1 to enable CAR T cell entry into tumor islets is of significance for improving CAR T strategy in solid tumors.

immunology↗