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Principal Investigator: Richard Thomas Wyatt
Organization: SCRIPPS RESEARCH INSTITUTE, THE
Fiscal Year: 2021
Award: $1,264,760
Funding agency: National Institute of Allergy and Infectious Diseases
The elicitation of cross-neutralizing or broadly neutralizing Abs (bNAbs) to diverse HIV strains by Env vaccination
remains a high priority for a broadly efficacious vaccine. The elicitation of bNAbs against conserved Env
determinants remains elusive; however, the recent isolation of bNAbs to the fusion peptide and other sites of
vulnerability demark promising leads in this process. Using N-glycan deleted NFL trimer-liposome priming and
heterologous boosting/restoration, cross-neutralizing responses in rabbits were elicited with isolation of a CD4
binding site (CD4bs)-directed bNAb, E70, and 1C2 (87% breadth) directed toward the gp120:gp41 interface, as
delineated by high resolution cryoEM (Dubrovskaya et al., Immunity 2019). More recently, we have also elicited
cross-neutralizing responses in guinea pigs using this approach with novel, full length stabilized “MIF” trimers as
well as autologous tier 2 neutralizing responses in wild type mice following mRNA lipid nanoparticle (LNP)
vaccination. Accordingly, the major objective of Project 1 will be to leverage these initial promising small animal
results to elicit bNAbs in non-human primates (NHPs) using an “epitope-targeted” approach against the CD4bs
and the gp120:gp41 trimer interface. As both sites are conserved Env protein determinants ringed by glycans,
the N-glycan deletion priming and restoration regimen will be further optimized. The NFL trimers will be modified
to enhance presentation of the targeted sites, while improving trimer stability and homogeneity by tail-anchoring
on covalently coupled trimer-liposomes, the cell surface from mRNA, or with a heterologous trimer motif (MIF).
The three presentation platforms will be cross-compared for effectiveness and translatability. Further, based on
studies indicating human infants and adolescents more readily develop bNAbs compared to HIV-infected adults,
immunization responses will be compared between juvenile and adult macaques. As a secondary objective, the
same regimens will be tested in guinea pigs to cross-validate the animal models. Guided approaches monitoring
“real-time” serum IgG responses by EM polyclonal epitope mapping (EMPEM; Core C) as well as rapid
monoclonal Ab (mAb) isolation (Project 2/VRC) will be utilized to inform boosting from a select, diverse panel of
structure-based, stabilized and homogeneous NFLs, iterative redesign and subsequent experiments. All NFL
trimers will be produced in Project 1 for the entire P01, validated by biophysical methods, including DSC, EM
and crystallography (Core C). Following elicitation of Env serum responses, isolated mAbs will be screened to
confirm elicitation and neutralization specificity. By these integrated processes and comprehensive analysis, we
will elicit and preferentially drive neutralizing antibodies to cross-neutralizing sites in primates in anticipation of
human testing in the clinic.
Terms: <21+ years old><7S Gamma Globulin><AIDS Virus><Acquired Immune Deficiency Syndrome Virus><Acquired Immunodeficiency Syndrome Virus><Adolescent><Adolescent Youth><Adult><Adult Human><Animal Model><Animal Models and Related Studies><Animals><Antigenic Determinants><Antigens><Antisera><Autologous><B blood cells><B cell><B cells><B-Cells><B-Lymphocytes><B-cell><Binding><Binding Determinants><Binding Sites><Blood Serum><Cavia><Cell surface><Clinic><Combining Site><Complex><Coupled><Cryo-electron Microscopy><Cryoelectron Microscopy><Crystallographies><Crystallography><Cysteine><Development><Disulfides><Domestic Rabbit><Electron Cryomicroscopy><Envelope Protein><Epitope Mapping><Epitopes><Glycans><Goals><Guinea Pigs><Guinea Pigs Mammals><HIV><HIV Envelope Glycoprotein gp120><HIV Envelope Protein gp120><HIV env Protein gp120><HIV-1 vaccine><HIV1 vaccine><HTLV-III gp120><Half-Cystine><Human><Human Immunodeficiency Viruses><IgG><Immune Sera><Immunity><Immunization><Immunoglobulin G><Immunologic Sensitization><Immunologic Stimulation><Immunological Sensitization><Immunological Stimulation><Immunostimulation><Infant><KLH><KLH antigen><Keyhole Limpet Hemocyanin><L-Cysteine><LAV-HTLV-III><Length><Liposomal><Liposomes><Lymphadenopathy-Associated Virus><Macaca><Macaque><Maps><Membrane><Messenger RNA><Modern Man><Modification><Molecular Interaction><Negative Staining><Oryctolagus cuniculus><Peptides><Polysaccharides><Primates><Primates Mammals><Process><Protomer><Public Health><Rabbits><Rabbits Mammals><Reactive Site><Regimen><Resolution><Serum><Site><Specificity><Structure><Tail><Techniques><Technology><Testing><Time><Translating><Vaccination><Vaccines><Validation><Virus-HIV><Wild Type Mouse><adulthood><alpha helix><base><biophysical approaches><biophysical methodology><biophysical methods><biophysical techniques><compare effectiveness><cryo-EM><cryoEM><design><designing><developmental><env Antigens><env Gene Products><env Polyproteins><env Protein><experiment><experimental research><experimental study><gp120><gp120 ENV Glycoprotein><gp120(HIV)><immune serum><immunogen><immunogenicity><improved><in vivo><juvenile><juvenile human><keyhole-limpet hemacyanin><lipid nanoparticle><mRNA><membrane structure><model of animal><model organism><neutralizing antibody><non-human primate><nonhuman primate><novel><real time monitoring><realtime monitoring><response><restoration><wildtype mouse><α-helix>