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Principal Investigator: WILLIAM R. SCHIEF
Organization: SCRIPPS RESEARCH INSTITUTE, THE
Fiscal Year: 2023
Award: $901,223
Funding agency: National Institute of Allergy and Infectious Diseases
Induction of broadly neutralizing antibodies (bnAbs) is a critical unmet goal of HIV vaccine
development. BnAb 10E8 is of particular interest as a vaccine lead due to its (1) very high
breadth, (2) low number of mutations required to develop broad neutralization, (3) low
auto-reactivity, (4) expected high frequency of precursors in the human na'ive B-cell pool and (5)
ability to provide surprisingly potent in vivo sterilizing protection in passive transfer studies.
Key challenges for inducing 10E8-like bnAbs are: (a) the low germline affinity by HIV peptides and
proteins, (b) the severe restriction on bnAb angle of approach imposed by the recessed,
membrane-proximal epitope environment and (c) the absence of the 10E8 epitope from most soluble,
native-like trimers (e.g. SOSIP or NFL or UFO).
A promising strategy to initiate 10E8-like bnAb induction is germline targeting, in which suitable
10E8-class precursors are specifically activated using engineered immunogens, thus selecting BCRs
with the potential to develop broad neutralization in the absence of autoreactivity. This approach
will also help circumvent steric problems associated with the recessed location of the epitope, by
priming precursors with known genetic and structural potential to mature into bnAbs compatible with
MPER steric restraints. In this proposal, we will engineer epitope-scaffold immunogens that
activate 10E8-like precursors, using computational design and directed evolution. We will initially
test immunogens ex vivo using human na'ive B cell sorting. We will further generate knock-in mice
that over-express 10E8-like precursors, and we will use those mice to test B-cell priming and
boosting in vivo, first adoptively transferring knockin B cells to wild- type mice in order to
mimic frequencies of 10E8 bnAb precursor and competitor B cells in humans.
As known bnAbs are highly mutated, vaccine induction of bnAbs following a germline prime will
likely require sequential immunization with other immunogens designed to shepherd affinity
maturation of the B-cell receptor. We will develop different classes of boosting immunogens,
including epitope-scaffolds with more native epitopes, membrane-protein scaffolds and
membrane-bound Env variants stabilized in a conformation to which 10E8 binds strongly. We will
conduct sequential prime/boost immunization experiments in knock-in mice and use ELISA, cytometry,
single B-cell sorting and sequencing and neutralization assays to track and optimize affinity
maturation.
In summary, these studies seek to develop novel HIV vaccine candidates and also to
shift HIV vaccine research towards a reductionist approach based on strategic
identification of bNAb precursors, state-of-the-art protein engineering to develop
germline-targeting and boosting immunogens, development of human Ig knock-in mouse models to enable
testing of human-repertoire-specific vaccines, and in-depth analysis of vaccine-induced affinity
maturation pathways in vivo to guide iterative vaccine optimization.
Terms: <AIDS Virus><Acquired Immune Deficiency Syndrome Virus><Acquired Immunodeficiency Syndrome Virus><Adoptive Transfer><Affinity><Animal Model><Animal Models and Related Studies><Antibodies><Antigenic Determinants><Antigens><Assay><Avidity><B blood cells><B cell><B cell differentiation><B cell receptor><B cells><B lymphocyte differentiation><B-Cell Activation><B-Cell Antigen Receptor><B-Cells><B-Lymphocytes><B-cell><B-cell receptor repertoire sequencing><B-cell receptor sequencing><BCR repertoire sequencing><BCR seq><BCR sequencing><BCRseq><Binding><Binding Determinants><Bioassay><Biologic Assays><Biological Assay><Biophysics><Cell Body><Cell Isolation><Cell Segregation><Cell Separation><Cell Separation Technology><Cells><Cytometry><Data><Development><Directed Molecular Evolution><ELISA><Engineering><Envelope Protein><Environment><Enzyme-Linked Immunosorbent Assay><Epitopes><Exhibits><Flow Cytofluorometries><Flow Cytofluorometry><Flow Cytometry><Flow Microfluorimetry><Flow Microfluorometry><Frequencies><Funding><Generations><Genetic><Genetic Alteration><Genetic Change><Genetic defect><Germ-Line Mutation><Germline Mutation><Glycans><Glycoproteins><Goals><HIV><HIV vaccine><HIV-1><HIV-I><HIV/AIDS Vaccines><HIV1><Health Priorities><Hereditary Mutation><Human><Human Immunodeficiency Virus Type 1><Human Immunodeficiency Viruses><Human immunodeficiency virus 1><Ig Somatic Hypermutation><Immune response><Immunity><Immunization><Immunoglobulin Somatic Hypermutation><Immunological response><In Vitro><Individual><Induced DNA Alteration><Induced Mutation><Induced Sequence Alteration><KI mice><Knock-in><Knock-in Mouse><LAV-HTLV-III><Lead><Liposomal><Liposomes><Location><Lymphadenopathy-Associated Virus><Mammalian Cell><Membrane><Membrane Protein Gene><Membrane Proteins><Membrane-Associated Proteins><Messenger RNA><Metabolic Glycosylation><Methods><Mice><Mice Mammals><Modeling><Modern Man><Molecular Configuration><Molecular Conformation><Molecular Interaction><Molecular Stereochemistry><Murine><Mus><Mutate><Mutation><NGS Method><NGS system><Passive Immunization><Pathway interactions><Pb element><Peptides><Physiologic><Physiological><Polysaccharides><Protein Engineering><Proteins><Regimen><Replication Unit><Replicon><Resistance><SHIV><Scaffolding Protein><Sorting><Specificity><Surface Proteins><Techniques><Testing><Vaccination><Vaccine Research><Vaccines><Variant><Variation><Viral><Virus><Virus-HIV><Virus-like particle><Wild Type Mouse><Yeasts><activated B cells><autoreactivity><biophysical foundation><biophysical principles><biophysical sciences><cell sorting><conformation><conformational><conformational state><conformationally><conformations><cross reactivity><design><designing><develop a vaccine><develop vaccines><development of a vaccine><developmental><directed evolution><env Antigens><env Gene Products><env Polyproteins><env Protein><enzyme linked immunoassay><experiment><experimental research><experimental study><experiments><flow cytophotometry><genetic protein engineering><genome mutation><germline variant><global health><glycosylation><heavy metal Pb><heavy metal lead><host response><human immunodeficiency virus vaccine><immune system response><immunogen><immunoresponse><improved><in vivo><interest><knockin><knockin mice><mRNA><membrane structure><model of animal><mouse model><murine model><nano particle><nano-sized particle><nanoparticle><nanosized particle><neutralizing antibody><next gen sequencing><next generation sequencing><nextgen sequencing><novel><overexpress><overexpression><pathway><protein design><protein reconstitution><prototype><resistant><response><restraint><scaffold><scaffolding><simian HIV><simian human immunodeficiency virus><somatic hypermutation><vaccine candidate><vaccine development><vaccine-related research><virus-like nanoparticles><viruslike particle><wildtype mouse>