Project description:Throughout life, humans experience repeated exposure to viral antigens through infection and vaccination, resulting in the generation of diverse, and largely unique, antigen specific antibody repertoires. A paramount feature of antibodies that enables their critical contributions in counteracting recurrent and novel pathogens, and consequently fostering their utility as valuable targets for therapeutic and vaccine development, is the exquisite specificity displayed against their target antigens. Yet, there is still limited understanding of the determinants of antibody-antigen specificity, particularly as a function of antibody sequence. In recent years, experimental characterization of antibody repertoires has led to novel insights into fundamental properties of antibody sequences, but has been largely decoupled from at-scale antigen specificity analysis. Here, using the LIBRA-seq technology, we generated a large dataset mapping antibody sequence to antigen specificity for thousands of B cells, by screening the repertoires of a set of healthy individuals against twenty viral antigens representing diverse pathogens of biomedical significance. Analysis uncovered virus specific patterns in variable gene usage, gene pairing, somatic hypermutation, as well as the presence of convergent antiviral signatures across multiple individuals, including the presence of public antibody clonotypes. Notably, our results showed that, for B cell receptors originating from different individuals but leveraging an identical combination of heavy and light chain variable genes, there is a specific CDRH3/CDRL3 identity threshold that defines whether these B cells may share the same antigen specificity. This finding provides a quantifiable measure of the relationship between antibody sequence and antigen specificity and further defines experimentally grounded criteria for defining public antibody clonality. Understanding the fundamental rules of antibody-antigen interactions can lead to transformative new approaches for the development of antibody therapeutics and vaccines against current and emerging viruses.
Project description:The sequence determinants of chromatin bivalency remain unclear. We analysed sequence determinants of chromatin bivalency genome-wide in several mammalian species and performed a series of transgenic experiments in mouse ES cells. Genome-wide mapping of H3K27me3 in rat ES cells and ChIP-seq with anti-Ezh2 antibody in transgenic mouse ES cells
Project description:Cells communicate with each other via receptor-ligand interactions. Here we describe lentiviral-mediated cell e¬ntry by engineered receptor-ligand interaction (ENTER) to display ligand proteins, deliver payloads, and record receptor specificity. We optimize ENTER to decode interactions between T cell receptor (TCR)-MHC peptides, antibody-antigen, and other receptor-ligand pairs. A viral presentation strategy allows ENTER to capture interactions between B cell receptor and any antigen. We engineer ENTER to deliver genetic payloads to antigen-specific T or B cells to selectively modulate cellular behavior in mixed populations. Single-cell readout of ENTER by RNA-sequencing (ENTER-seq) enables multiplexed enumeration of antigen specificities, TCR clonality, cell-type and states of individual T cells. ENTER-seq of CMV-seropositive patient blood samples reveals the viral epitopes that drive effector memory T cell differentiation and inter- vs intra-clonal phenotypic diversity targeting the same epitope. ENTER technology enables systematic discovery of receptor specificity, linkage to cell fates, and antigen-specific cargo delivery.
Project description:Cells communicate with each other via receptor-ligand interactions. Here we describe lentiviral-mediated cell e¬ntry by engineered receptor-ligand interaction (ENTER) to display ligand proteins, deliver payloads, and record receptor specificity. We optimize ENTER to decode interactions between T cell receptor (TCR)-MHC peptides, antibody-antigen, and other receptor-ligand pairs. A viral presentation strategy allows ENTER to capture interactions between B cell receptor and any antigen. We engineer ENTER to deliver genetic payloads to antigen-specific T or B cells to selectively modulate cellular behavior in mixed populations. Single-cell readout of ENTER by RNA-sequencing (ENTER-seq) enables multiplexed enumeration of antigen specificities, TCR clonality, cell-type and states of individual T cells. ENTER-seq of CMV-seropositive patient blood samples reveals the viral epitopes that drive effector memory T cell differentiation and inter- vs intra-clonal phenotypic diversity targeting the same epitope. ENTER technology enables systematic discovery of receptor specificity, linkage to cell fates, and antigen-specific cargo delivery.
Project description:Hepatitis B virus (HBV) core antigen (HBc) is a structural protein that forms the viral nucleocapsid and is involved in various steps of the viral replication cycle, but its role in the pathogenesis of HBV infection is still elusive. In this study, we generated a mouse monoclonal antibody against HBc and used it in an antibody-based in situ biotinylation to identify the host proteins that interact with HBc.
Project description:Post-translational modifications (PTMs) of proteins play critical roles in regulating many cellular events. Antibodies targeting site-specific PTMs are essential tools for detecting and enriching PTMs at sites of interest. However, fundamental difficulties in molecular recognition of both PTM and surrounding peptide sequence have hindered the efficient generation of highly specific anti-PTM antibodies. Furthermore, the widespread use of potentially inconsistent, non-renewable and molecularly undefined antibodies presents experimental challenges thought to contribute to the reproducibility crisis in biomedical research. In this study, we describe the structure-guided development of a platform that efficiently generates potent and selective recombinant antibodies to PTMs that are molecularly-defined and infinitely renewable. Our platform is built on our previous discovery of an unconventional binding mode of anti-PTM antibodies, antigen clasping, where two antigen binding sites cooperatively clasp a single antigen, creating extensive interactions with the antigen and leading to high selectivity and potency. We designed the platform that generates clasping antibodies with two distinct binding units, resulting in efficient generation of antibodies to a set of trimethylated histone H3 with high levels of specificity and affinity. Performance comparison in chromatin immunoprecipitation (ChIP), a common application in epigenomics, revealed that an anti-H3K27me3 clasping antibody exhibited superior specificity to a widely-used conventional antibody and captured symmetric and asymmetric nucleosomes in a less biased manner. We further generated clasping antibodies to phosphotyrosine antigens by using the same principle. These results suggest the broad applicability of our platform to generating high-performance clasping antibodies to diverse PTMs.