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8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Dale and Betty Bumpers
Vaccine Research CenterNational Institute of Allergy and Infectious Diseases
National Institutes of Health
Department of Health and Human Services
Gary J. Nabel M.D., Ph.D.
Vaccine Research Center
NIAID, NIH
Sept. 28, 2010
HIV Vaccine Enterprise: Progress in Basic Research
International AIDS Vaccine Meeting
2010
Atlanta, GA
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Acquisition vs.Viral Load:Acquisition vs.Viral Load:
Independent ParametersIndependent Parameters
Vaccination to Prevent AcquisitionVaccination to Prevent Acquisition
XX
XX
XX
Vaccination to Control ViremiaVaccination to Control Viremia
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1. Blocking infection vs. controlling viral load
2. Paradigm for HIV vaccine development differs
from all licensed vaccine: basic science drivesprogress in rational vaccine design.
3. Basic science is done in clinical trials
Key Issues in AIDS Vaccine Development
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Time (months
1
ViralLoa
d
2 3 4 5
How Might a Vaccine Prevent Infection?
Scenario 1: No Immune Protection
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Time (months
1
ViralLoa
d
2 3 4 5
How Might a Vaccine Prevent Infection?
Scenario 2: Broadly Neutralizing Antibodies
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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-
CD8 CTLCD8 CTLCD8 CTLCD8 CTLTime (months
1
ViralLoa
d
2 3 4 5
How Might a Vaccine Prevent Infection?
Scenario 3: Highly Effective T Cell Vaccine
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Time (months
1
ViralLoa
d
2 3 4 5
How Might a Vaccine Prevent Infection?
Scenario 4: Partially Effective nAb Response
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CD8 CTLCD8 CTLCD8 CTLCD8 CTL CD8 CTLCD8 CTLCD8 CTLCD8 CTL
Time (months
1
ViralLoa
d
2 3 4 5
How Might a Vaccine Prevent Infection?
Scenario 5: Partially Effective nAb and T Cells
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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1. T cell vaccine vectors and concepts
2. Advances in B cell immunogen design
3. Modeling of HIV infection in the non-human
primate
Basic Science and AIDS Vaccine Development
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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1. T cell vaccine vectors and concepts
2. Advances in B cell immunogen design
3. Modeling of HIV infection in the non-human
primate
Basic Science and AIDS Vaccine Development
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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New Vectors and Combinations DNA prime + adenoviral vector boost
Heterologous rAd vector prime/boost
LCMV prime/boost
Chimp and simian Ads
Integrase-deficient lentiviral vectors
Next Generation T Cell Vaccines
Sim rAdrAd41rAd35rAd28rAd26rAd5 ch rAd rLCMV rLVV
Human rAds simian Ads non Ads
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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New Vectors and Combinations DNA prime + adenoviral vector boost
Heterologous rAd vector prime/boost
LCMV prime/boost
Chimp and simian Ads
Integrase-deficient lentiviral vectors
Next Generation T Cell Vaccines
Sim rAdrAd41rAd35rAd28rAd26rAd5 ch rAd rLCMV rLVV
Human rAds simian Ads non Ads
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Next Generation Inserts: Expanding Breadth
Informatically
B. Korber, B. Hahn, Norm Letvin, Bart Haynes
HIV/SIV Gag Chimeras and
Chimeric Mosaics
Mosaics (Env, Gag, Pol, Nef)
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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1. T cell vaccine vectors and concepts
2. Advances in B cell immunogen design
3. Modeling of HIV infection in the non-human
primate
Basic Science and AIDS Vaccine Development
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Neutralizing mAbs as of 2008
2F5, 4E10
(1993, 1994)
gp120trimer
2G12 (1996)
447-D (1993)
gp41
b12 (1994)
CD4bs
Co-receptor
bs
V3
Until last year (2009) - No new
broadly NAb since 1996
NAbs were unable to explain the
potent neutralization found in
some sera
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Laura M Walker and Dennis R Burton
Current Opinion in Immunology 2010
2010: New Potent mAbs against
Model of known neutralization epitopes based on
atomic level structure of gp120 and the
cryoelectron tomographic structure of trimeric Env
VRC01 - 03
HJ16
(CD4bs)
2G12(glycan)
2F5, Z13, 4E10
MPER
Liu/Subramaniam Nature 2008
Zhou/Kwong Nature 2007
PG9/16
(V2/V3 region)
PG9/16 Quaternary neutralizationepitope in regions of V2/V3
VRC01, 02, 03 target CD4bs
Neutralize more potently, and with
far more breadth than prior mAbs(80% - 90%); often < 1 ug/ml
Additional new potent and broadly
reactive NAbs at this meeting
PG9/16
(V2/V3region
)
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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A Proof of Concept for Vaccines?
Broad and Potent Neutralizing Antibodies are
Synthesized in Natural HIV-1 Infection
Doria-Rose, Wyatt, Korber, Mascola, Connors et al. J Virol 83:188-199 (2009) VRC/NIAID: 110 clade B sera
Sather/Stamatatos J Virol 83:757-769 (2009) SBRI/Vanderbilt: 64 clade B sera
Simek, Burton, Koff et al; J Virol 83: 7337-7448 (2009) IAVI protocol G: >1700 clade A, B, C, D, E sera
Gray, Montefiori, Mascola, Morris et al. J. Virol. 83:8925-37 (2009): SAAVI/CHAVI/CAVD 70 clade C sera
15 - 25% sera display
significant cross-clade breadth
of neutralization-to what are
they directed?> 150
> 500
ID50
Sera
Viruses
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Strategy for Isolation of New Monoclonal Antibodies Based
On HIV Protein Structure
Nabel, Schief, Kwong, Mascola
Resurfaced Stabilized Cores (RSC)
Designer Envelopes
OuterInnerStabilizing inner
domain and
bridging sheet
Stabilizing the
inner/outer
domains
Core Stabilized Core
Mascola et al. VRC Broadly Neutralizing Ab Isolation
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X
RSC3 RSC3
Biotin
SA-APC SA-PE
Resurfaced Stabilized Cores (RSC) as
Epitope-Specific Probes for B-Cell Isolation
Kwong, Schief, Zhou, Nabel
Wu et al. Science (2010) 329:856
gp120 core
resurfaced
residues glycans
Bill Schief
Gary Nabel (ZY Yang)
Peter Kwong (T Zhou
CD4 binding
site
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Strategy for Isolation of New mAbsBased on
Epitope Specific Protein Probes
+
X
RSC3
(positive)
RSC3(negative)
epitope specific B cells
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Three mAbs bind to the RSCprotein
0.0001 0.001 0.01 0.1 1 100
1
2
3
4
mAb (g/ml)
OD450
0.0001 0.001 0.01 0.1 1 100
1
2
3
4
VRC02 g/ml0.0001 0.001 0.01 0.1 1 100
1
2
3
4
VRC03 g/ml
VRC01 VRC02 VRC03
Two closely related somatic variants (VRC01, VRC02)
bind to CD4bs region of gp120
Neutralize ~90% viruses, often < 1ug/ml
1 additional mAb (VRC03)
CD4bs directed
Neutralizes ~ 60% viruses
RSC
RSC/d371I
Wu et al. Science (2010) 329:856
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0.01
IC50 < 1 g/ml
IC50
1-50 g/ml
IC50 > 50 g/ml
VRC01
HXB2
B
G
CRF02_AG
A CRF0
1_AE
C
D
CRF0
7_
BC
b12
HXB2
IC50 < 50 g/ml IC50 < 1 g/ml
Virus clade Number ofviruses
VRC01 b12 VRC01 b12
A 22 100% 45% 95% 23%
B 49 96% 63% 80% 39%
C 38 87% 47% 66% 13%
D 8 88% 63% 50% 25%
CRF01_AE 18 89% 6% 61% 0%
CRF02_AG 16 81% 19% 56% 0%
G 10 90% 0% 90% 0%
CRF07_BC 11 100% 27% 45% 9%
Other 18 83% 33% 78% 6%
Total 190 91% 41% 72% 17%
gp160 protein distance
Neighbor-Joining tree
Panel of 190 Diverse Viral IsolatesMike Seaman
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Crystal Structure of VRC01:gp120
gp120 outer domain
Light chainHeavy chain
Inner domain
CDR H2
CD4 binding loop
Loop D
Loop V5
CDR H1CDR H3CDR L1CDR L3
Zhou/Kwong Science (2010) 329;811
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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gp120
CD4 and VRC01 in highly similar positions
Mimicry of CD4 Receptor byAntibody VRC01
gp120
CD4
VRC01
heavy chain
V-domain
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Why does VRC01 Work So Well?
1. Partial mimicry
of CD4 binding
to gp120
2. Binding
focused on the
conformational
ly invariant site
of initial CD4
attachment.
gp120inner domain
gp120outer domain
bridging sheet
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Structural Models of Alternative Forms of HIV-1 Envelope
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Induction of CD4 BS Antibodies by Trimeric Immunogens
in Rabbit
R f d S bili d C P b f H Ab d
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Resurfaced Stabilized Cores: Probes for Human Abs and
Templates for Immunogens
Nabel, Schief, Kwong, Mascola
Resurfaced Stabilized CoresCores
Alter surfaceresidues to eliminate
reactivity with non-
neutralizing
antibodies
1. Probe to isolate B cells and clone broadly neutralizing abs
2. Prototype immunogens to elicit antibodies to the highly
conserved CD4 binding site
CD4
binding site
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Scope of Clinical Applications of
Anti-HIV Neutralizing Antibodies
Scope
Prevention
Therapy
Eradication of
reservoir
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Anti-HIV Neutralizing Antibodies
Scope
Prevention- Topical microbicides
- Regulated gene expression
(e.g. AAV, lentiviral vectors)
- Passive infusion (systemic)
Therapy
Eradication of
reservoir
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Scope
Prevention
Therapy Passive infusion - antiviral
Combination of antibodies
Combination of drugs/antibodies
Eradication of reservoir
Anti-HIV Neutralizing Antibodies
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Anti-HIV Neutralizing Antibodies
Scope
Prevention
Therapy
Eradication of reservoir- Fc mediated: Virolysis, ADCC- Targeting viral reservoirs
Ab-toxin chimeras
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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1. T cell vaccine vectors and concepts
2. Advances in B cell immunogen design
3. Modeling of HIV infection in the non-human
primate
Basic Science and AIDS Vaccine Development
Vaccine Mediated Protection Against
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Acquisition of Established Infection
Vaccine-Mediated Protection Against
SIVsmE660 Infection
Vaccine
Control
Plasmalog
10
RNAco
pi e
s/mL
Peak Viral Load
p = 0.31
Control Vaccine
Letvin, Mascola et al., VRC NHP Studies
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The Three Pillars of a Highly Effective AIDS VaccineThe Three Pillars of a Highly Effective AIDS Vaccine
Clinical Efficacy TrialsClinical Efficacy Trials
Non-human PrimateNon-human Primate
ModelsModelsNeutralizing AntibodiesNeutralizing Antibodies
and T cell immunogensand T cell immunogens
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mAb Isolation Acknowledgments
VRC and NIAID
Xueling Wu
Yuxing Li
Rich Wyatt
Mark Connors
Nicole Doria-Rose
Krisha McKee Mark Louder
Sijy ODell
Steve Schmidt
Diane Wycuff
Mario Roederer
Carl Hogerkorp
Tongqing Zhou Zhi-Yong Yang
Peter Kwong
John Mascola
Collaborators
Bill Schief
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External Viral Protein
Envelope
The Neutralizing Antibody Vaccine ConceptThe Neutralizing Antibody Vaccine Concept
A broad and potent neutralizing antibody response will prevent
HIV infection or control HIV disease through inactivation of virus
and/or by mobilization of antibody-dependent or innate immune
responses to virus infected cells .
HIV-infected cells
Cell-free virus Neutralizing antibodies
CD4 Provirus
ADCC, ComplementEnv
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Structure Based Vaccine Design
Recessed receptor binding sites:
CD4 and CCR5 Decoy effects from monomer and V regions:
induction of non-neutralizing antibodies
M j C f i l Al i f HIV E
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Unbound CD4-bound conformation
Major Conformational Alterations of HIV Env
Upon Engaging the CD4 Receptor
The coreceptor binding domain is only formed
after CD4 engagement.
Chen et al. & Harrison, Nature 2005
Structure Assisted Vaccine Design:
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Mutagenic stabilization of the CD4-bound conformation of
gp120: have engineered four domain-stabilizing disulfides
and three cavity-filling mutants. (Zhou, et al. & Wyatt, Nabel & Kwong)
Structure Assisted Vaccine Design:
Constraint of Conformational Flexibility
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Tongqing Zhou et al. Nature 445,732-737
b12 binds to gp120
conformational
invariant surface.
Overall Structure of b12:gp120 Complex
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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A Site of Vulnerability on HIV-1
b12 E it St t B D i
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Trimers
Monomeric gp120 (core) and cloaks
Outer domain of gp120
Scaffolding
b12-Epitope Structure-Base Design
Outer Domain
CD4-bindingloop
Complex epitope
gp120 core cloaked core
b12 E it St t B D i
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Trimers
Monomeric gp120 (core) and cloaks
Outer domain of gp120
Scaffolding
b12-Epitope Structure-Base Design
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Kwong et al. J Virol 2000.
Modeled HIV-1 Env Trimer and Glycan Shield
90 rotation
b12 E it St t B D i
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Trimers
Monomeric gp120 (core) and cloaks
Outer domain of gp120
Scaffolding
b12-Epitope Structure-Base Design
gp120 core cloaked core
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Cloaking of Irrelevant HIV gp120 Surface
Determinants with SIV
180o
Cloak siv_8b_11_2a
Cloak 2NXY-11b-comp-6e_0007
Inner domain Outer domain
Bridging Sheet
Core (8B)
Wild type HXB2
CD4 binding
loop
D i Vi f CD4
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Designs: View from CD4
Binding Face
2nxy_11b_1 siv_8b_sg_11b siv_8b_11_2a 2nxy-11b-comp-6e_0007
2nxy-
polar1pt5_01772nxy-11b-
redes-8_0105
2nxy-11b-
redes-8_01052nxy-11b-
comp-2g_0017
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Designs: View from Backside
2nxy_11b_1 siv_8b_sg_11bsiv_8b_11_2a 2nxy-11b-
comp-6e_0007
2nxy-11b-
comp-2g_0017
2nxy-11b-
redes-8_0105
2nxy-
polar1pt5_0177
2nxy-IIc-
25_0188
f i
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Model of Free Trimer
b12 Trimer Structure Model
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b12 Trimer Structure Model
M d l f F T i
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Model of Free Trimer
Cl ki f I l t HIV 120 S f
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Cloaking of Irrelevant HIV gp120 Surface
Determinants with SIV
180o
Cloak siv_8b_11_2a
Cloak 2NXY-11b-comp-6e_0007
Inner domain Outer domain
Bridging Sheet
Core (8B)
Wild type HXB2
CD4 binding
loop
St t l M d l f Alt ti F f HIV 1 E l
8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)
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Structural Models of Alternative Forms of HIV-1 Envelope
Competition of CD4 BS Antibodies in Rabbit Antisera
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p
by IgG1 b12 and b13