progress in basic research (gary j. nabel, m.d., ph.d.)

8/7/2019 Progress in Basic Research (Gary J. Nabel, M.D., Ph.D.)

1/56

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


2/56

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


3/56

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


4/56

Time (months

1

ViralLoa

d

2 3 4 5

How Might a Vaccine Prevent Infection?

Scenario 1: No Immune Protection


5/56

Time (months

1

ViralLoa

d

2 3 4 5


Scenario 2: Broadly Neutralizing Antibodies


6/56

-

CD8 CTLCD8 CTLCD8 CTLCD8 CTLTime (months

1

ViralLoa

d

2 3 4 5


Scenario 3: Highly Effective T Cell Vaccine


7/56

Time (months

1

ViralLoa

d

2 3 4 5


Scenario 4: Partially Effective nAb Response


8/56

CD8 CTLCD8 CTLCD8 CTLCD8 CTL CD8 CTLCD8 CTLCD8 CTLCD8 CTL

Time (months

1

ViralLoa

d

2 3 4 5


Scenario 5: Partially Effective nAb and T Cells


9/56

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


10/56




primate



11/56

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


12/56

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


13/56

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)


14/56




primate



15/56

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


16/56

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

)


17/56

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


18/56

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


19/56

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


20/56

Strategy for Isolation of New mAbsBased on

Epitope Specific Protein Probes

+

X

RSC3

(positive)

RSC3(negative)

epitope specific B cells


21/56

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


22/56

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


23/56

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


24/56

gp120

CD4 and VRC01 in highly similar positions

Mimicry of CD4 Receptor byAntibody VRC01

gp120

CD4

VRC01

heavy chain

V-domain


25/56

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


26/56

Structural Models of Alternative Forms of HIV-1 Envelope


27/56

Induction of CD4 BS Antibodies by Trimeric Immunogens

in Rabbit

R f d S bili d C P b f H Ab d


28/56

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


29/56

Scope of Clinical Applications of

Anti-HIV Neutralizing Antibodies

Scope

Prevention

Therapy

Eradication of

reservoir


30/56


Scope

Prevention- Topical microbicides

- Regulated gene expression

(e.g. AAV, lentiviral vectors)

- Passive infusion (systemic)

Therapy

Eradication of

reservoir


31/56

Scope

Prevention

Therapy Passive infusion - antiviral

Combination of antibodies

Combination of drugs/antibodies

Eradication of reservoir



32/56


Scope

Prevention

Therapy

Eradication of reservoir- Fc mediated: Virolysis, ADCC- Targeting viral reservoirs

Ab-toxin chimeras


33/56




primate


Vaccine Mediated Protection Against


34/56

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


35/56

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


36/56

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


37/56


38/56

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


39/56

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


40/56

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:


41/56

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


42/56

Tongqing Zhou et al. Nature 445,732-737

b12 binds to gp120

conformational

invariant surface.

Overall Structure of b12:gp120 Complex


43/56

A Site of Vulnerability on HIV-1

b12 E it St t B D i


44/56

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


45/56

Trimers



Scaffolding



46/56

Kwong et al. J Virol 2000.

Modeled HIV-1 Env Trimer and Glycan Shield

90 rotation

b12 E it St t B D i


47/56

Trimers



Scaffolding


gp120 core cloaked core


48/56

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


49/56

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


50/56

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


51/56

Model of Free Trimer

b12 Trimer Structure Model


52/56

b12 Trimer Structure Model

M d l f F T i


53/56

Model of Free Trimer

Cl ki f I l t HIV 120 S f


54/56

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


55/56

Structural Models of Alternative Forms of HIV-1 Envelope

Competition of CD4 BS Antibodies in Rabbit Antisera


56/56

p

by IgG1 b12 and b13

progress in basic research (gary j. nabel, m.d., ph.d.)

Documents