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Principal Investigator: Mikyung Kim
Organization: DANA-FARBER CANCER INST
Fiscal Year: 2024
Award: $1,013,381
Funding agency: National Institute of Allergy and Infectious Diseases
SUMMARY – PROJECT 1
Neutralizing antibodies are a major component of vaccine-induced protective immunity. However, induction of
broadly neutralizing antibody (bnAb) against the trimeric HIV-1 envelope (Env) spike protein gp160 continues to
be a challenging goal. An effective vaccine must address the remarkable antigenic variability of gp160, its
extensive glycan shield and/or conformational masking of conserved neutralizing target epitopes. Among bnAb
targets, the membrane proximal external region (MPER) of gp41, the Env subunit critical for virus fusion, is
attractive given its linear and highly conserved sequence as validated by the neutralization breadth of 4E10,
10E8 and DH511 bnAbs. Nonetheless, the poorly immunogenic nature of the MPER during the natural course of
infection and the lack of neutralizing activities elicited by structure-based MPER immunogens demand an
alternative immunogen design approach. The accessibility of the MPER is limited, being shielded by gp160
trimer ectodomain from above and the viral membrane from below. Furthermore, our recent MPER/liposome
results suggest that the unrestricted approach angle afforded to the B cell receptor with current vaccine
formulation is problematic, inducing a majority of polyclonal Abs as well as recombinant monoclonal Abs that lack
Env reactivity. Therefore, MPER immunogens must mimic spatial occlusion while enforcing limited Ab
accessibility to the MPER in a manner analogous to that imposed by the quaternary structural configuration of
gp160 on the virion surface. In that regard, our recent analyses of the trimeric HIV-1 Env structure and molecular
dynamics (MD) in nanodiscs provide compelling data for novel vaccine design considerations. With advanced
messenger RNA lipid nanoparticle (mRNA-LNP) vaccine technology, Project 1 proposes to create novel
mRNA-based immunogens that encode trimeric spike-MPER-TM (the MPER and adjacent transmembrane
segment) chimeras. Therein the Env ectodomain is replaced by structurally suitable host self-proteins, focusing
Ab responses solely against the conjoint membrane-arrayed viral MPER-TM epitopes. In Aim1, a pipeline
involving automated computational searches of the PDB followed by MD and single-particle cryo-electron
microscopy (cryoEM) structures in collaboration with Project 2 will generate multiple candidate immunogens.
Optimization and further modifications of mRNA-LNP vaccines will be tested by 1) in vitro expression, 2)
antigenicity and antigen presentation, and 3) in vivo immunogenicity studies. The latter use knock-in (KI) mice
harboring introduced human Ig D3-3 and JH6 gene segments for long CDRH3 generation. In Aim 2, genetic,
biochemical and functional characteristics of vaccine-elicited Abs at the single B cell level will be determined and
compared with human bnAbs analyzed structurally in Project 2. The integrated analyses will offer iterative
immunogen improvements to enhance the quantity and quality of anti-MPER Abs. In Aim 3, strategies will be
developed to prime germline bnAb precursors and then selectively expand memory B cells by heterologous
boosting to generate long-lived plasma cells in bone marrow producing high titer bnAbs in plasma.
Terms: <Ab response><Address><Affinity><Antibodies><Antibody Formation><Antibody Production><Antigen Presentation><Antigen Variation><Antigenic Determinants><Antigenic Variability><Antigenic Variation><Antigens><B blood cells><B cell><B cell receptor><B cells><B-Cell Antigen Receptor><B-Cells><B-Lymphocytes><B-cell><Binding><Binding Determinants><Binding Proteins><Biochemical><Blood Plasma><Blood Plasma Cell><Blood Serum><Bone Marrow><Bone Marrow Reticuloendothelial System><C 2a><C2a><Cell Body><Cell Isolation><Cell Lineage><Cell Segregation><Cell Separation><Cell Separation Technology><Cell surface><Cells><Characteristics><Chimera><Chimera organism><Clinical Treatment Moab><Collaborations><Computers><Conserved Sequence><Cryo-electron Microscopy><Cryoelectron Microscopy><Data><Data Bases><Databases><Development><Electron Cryomicroscopy><Epitopes><Evaluation><Fostering><Generations><Genes><Genetic><Genetic Alteration><Genetic Change><Genetic defect><Germ Lines><Glycans><Goals><HIV-1><HIV-I><HIV1><Human><Human Immunodeficiency Virus Type 1><Human immunodeficiency virus 1><Immune response><Immunity><Immunization><Immunodominant Antigenic Determinants><Immunodominant Determinants><Immunodominant Domains><Immunodominant Epitopes><Immunodominant Regions><Immunodominant Sites><Immunological response><In Vitro><Individual><Infection><KI mice><Knock-in Mouse><Length><Ligand Binding Protein><Ligand Binding Protein Gene><Link><Lipid Binding><Liposomal><Liposomes><Locales><Membrane><Membrane Protein Gene><Membrane Proteins><Membrane-Associated Proteins><Memory B Cell><Memory B-Lymphocyte><Messenger RNA><Mice><Mice Mammals><Modern Man><Modification><Molecular Configuration><Molecular Conformation><Molecular Dynamics Simulation><Molecular Interaction><Molecular Stereochemistry><Monoclonal Antibodies><Mouse Protein><Murine><Mus><Mutation><Nature><Non-Polyadenylated RNA><Plasma><Plasma Cells><Plasma Serum><Plasmacytes><Polysaccharides><Protein Binding><Proteins><Protomer><RNA><RNA Gene Products><Recombinants><Regimen><Reticuloendothelial System, Serum, Plasma><Ribonucleic Acid><Serum><Shapes><Specificity><Structure><Surface><Surface Proteins><Technology><Testing><Vaccination><Vaccine Design><Vaccines><Variant><Variation><Viral><Virion><Virus><Virus Particle><antibody biosynthesis><bound protein><cell sorting><chimeras><complement 2a><complement C2a><complement C2a fragment><conformation><conformational><conformational state><conformationally><conformations><cryo-EM><cryoEM><cryogenic electron microscopy><data base><design><designing><developmental><genome mutation><gp160><host response><immune system response><immunization strategy><immunogen><immunogenic><immunogenicity><immunoglobulin biosynthesis><immunoresponse><improved><in vivo><knockin mice><lipid based nanoparticle><lipid bound><lipid nanoparticle><mAbs><mRNA><membrane structure><mimicry><molecular dynamics><monoclonal Abs><monoclonal antibody production><nanodisk><neutralizing antibody><new vaccines><next generation vaccines><novel><novel vaccines><particle><plasmocyte><programs><response><screening><screenings><vaccination strategy><vaccine formulation>