Properties of the immune system 1. Specificity 2. Diversity 3. Memory
Clonal Selection Theory
Ag
B
DC T
Diversity Specificity Memory Burnet, Lederberg, Talmage
VDJ Rearrangement 134 V
13 D
4 J
C
• Combinatorial diversity: ~2.5 x106 • Junctional diversity: >1014 • Human: ~1011 B cells • Mouse: ~5 x 107 B cells
Antibody Affinity Maturation:
H.N. Eisen & G.W. Siskind, Biochemistry, 1964
Cellular basis of affinity maturation 1. Diversification 2. Affinity-based selection AID
Antibody Affinity
B T
LZ
DZ
Naïve B cells GC B cells FDCs
Schwickert et al Nature 2008 Victora et al Cell 2010
The Germinal Center Produces Plasma Cells and Memory B cells memory B cell TFH cell
TCR
FDC Plasma cell BCR
Apoptotic cell
memory B cell
LZ DZ
GC B cell
Act B cell CD38+ GL7+
B cell follicle
T cell
T cell zone
Plasma Cells are Selected for High Affinity
AID
Plasma Cells Antibody Affinity
Cellular basis of memory formation 1. Diversification
AID
Memory Cells Antibody Affinity Viant et al Cell 2020
5-10% of HIV+ individuals develop broadly neutralizing serum antibodies BUT only after 2-3 years and this has not been reproduced in vaccines
1. Select elite serologic responders (top 5%)
Antibody Discovery
2. Enrich for B cells from donor PBMCs.
3. Incubate donor B cells with labelled antigen.
4. Singlecell sort doublepositive B cells, and clone antibody genes.
Wardemann et al., Science 2003 Scheid et al., Nature 2009
Pseudotype Virus Neutralization Assay
HIV-1pp NT50 SARS-CoV-2 NT50
1000 100
32 5 120 107 55 183 310 393 56 280 325 460 182 394 547 205 201 21 72 47
NT50
10000
10
R2 =0.58, p<0.0001 Spearmans r=0.91, p<0.0001
1000
SARS2-CoV-2 IC50 (ng/ml)
100000
C
Plasma
100
10
1 1 10 100 1000 HIV-1NL ΔEnv-NanoLuc IC50 (ng/ml)
Schmidt et al JEM 2020 Robbiani et al Nature 2020
Rockefeller University CoViD19 Response •
http://clinicalstudies.rucar es.org/coronavirus.php
•
April 1, 2020 – May 4th, 2020, 2077 volunteers screened
•
Plasma, serum and PBMC processed and stored from 148 selected volunteers
•
Rapid ELIZA, and Neutralization assays
•
Cell sorting and antibody cloning
Variable Neutralizing Titers After Infection And Decreased Neutralizing Activity Over 6 Months
Gaebler et al Nature 2021
NT50
Neutralizing Antibody Levels After Vaccination
103
102 R=0.69 p=0.0008
101 25
50
75
100
Time in days
125
150
Gaebler et al Nature 2021 Wang et al Nature 2021
SARS-CoV-2 Spike Bound to its Cellular Receptor ACE-2 RBD
ACE2 down RBD
up RBD
NTD
NTD
NTD S1 S2
Viral Membrane
Isolation of antiSARS2 Antibodies
Wardemann et al. Science 2003; Scheid et al. Nature 2009
Anti-RBD Memory B cells Increased and Clones Evolve After 6 Months
Gaebler et al Nature 2021
Shared Antibodies Among Convalescent and Vaccinated Individuals
Robbiani, Nussenzweig Nature 2020 Gaebler, Nussenzweig Nature 2021 Wang Nussenzweig Nature 2021
Summary 1. Infected individuals retain serum neutralizing activity after 6 months but it is 5X decreased from the peak. 2. Memory B cells persist after SASRS-CoV-2 infection for over 6 months 3. mRNA vaccination and natural infection elicit similar levels of plasma neutralizing antibodies 4. Older individuals produce more modest responses to vaccine 5. Vaccination prevents serious disease but does not prevent infection 6. The half-life of mRNA elicited antibody responses appears to be shorter than natural infection 7. mRNA vaccination and natural infection elicit similar levels of memory B cells 8. Monoclonal anti-RBD antibodies produced during natural infection are closely related to antibodies elicited by vaccination Gaebler et al Nature 2021 Bretton et al JEM 2021
SARS-CoV-2 Spike Bound to its Cellular Receptor ACE-2 RBD
ACE2 down RBD
up RBD
NTD
NTD
NTD S1 S2
Viral Membrane
Common Theme For Group 1 SARS-CoViD-2 Binding to Open RBD
Barnes et al Cell 2020
Top Monoclonals are Sensitive to Mutations in Emerging Variants
Class 1 Antibodies are Generally Sensitive to K417N and N501Y
Wang, Nussenzweig Nature 2021
Class 2 Antibodies are Generally Sensitive to E484K
Wang, Nussenzweig Nature 2021
Decreased Plasma Activity Against Circulating Variants
Vaccinees
Convalescent 1.3 month
6.2 month
Wang et al Nature 2021
A replication competent VSV/SARSCoV-2 chimera rVSV/SARS-2
N
10μg/ml mAb or plasma dilution
P
M
SARS-CoV-2 Spike (Δ19)
10μg/ml mAb or plasma dilution
1x106 IU rVSV/SARS-CoV-2/GFP
p1
p2
EGFP
Sequence, Isolate mutants by limiting dilution
L
Sequence
Plasma [5x initial]
Plasma [5x initial]
p3
p4
Sequence, Isolate mutants by limiting dilution
Schmidt et al ELife 2020
Antibody Selection is Consistent with Sensitivity Mapping and Structure
Wang et al Nature 2021
Summary 1. Vaccinee and convalescent plasma have reduced activity against emerging SARS-CoV-2 variants 2. Monoclonal anti-RBD antibodies are sensitive to emerging SARS-CoV-2 mutations 3. Antibodies select for the same RBD mutations as in the emerging variants in VSV pseudotyped with SARS-CoV-2 S in vitro
Wang et al Nature 2021
What is the Role of Passive Antibody Administration • Protection - individuals that cannot respond to vaccine. For example, individuals undergoing cancer therapy or immunotherapy. • Therapy –infected individuals receiving antibodies early are protected from severe outcomes. This can be a very large group including those that fail to respond or mount sub-optimal responses to vaccine and those that whatever reason do not take the vaccine.
Rockefeller University CoViD19 Response •
http://clinicalstudies.rucar es.org/coronavirus.php
•
April 1, 2020 – May 4th, 2020, 2077 volunteers screened
•
Plasma, serum and PBMC processed and stored from 148 selected volunteers
•
Rapid ELIZA, and Neutralization assays
•
Cell sorting and antibody cloning
Isolation of antiSARS2 Antibodies
Wardemann et al., Science 2003; Scheid et al., Nature 2009
Moderna and Pfizer Vaccinee and Convalescent Antibodies are Closely Related
Four Classes of Neutralizing Human Monoclonals
Antibody Selection is Consistent with Sensitivity Mapping and Structure
Wang et al BioRix 2021
Acknowledgement Nussenzweig Lab Davide Robbiani Gaelle Bretton Julio Lorenzi Zijun Wang Alice Cho Shlomo Finkin Thomas Hagglof Charlotte Viant Pilar Mendoza Anna Gazumyan Marianna Agudelo Melissa Chipolla Dennis Schaefer-Babajew
Bjorkman Lab Christopher Barnes Anthony West Morgan Abernathy Kathryn Huey-Tubman Morgan Abernathy
Bieniasz Lab Frauke Muecksch Fabian Schmidt Yiska Weisblum Theodora Hatziioannou
Caskey Clinical Group Christian Gaebler Jill Horwitz Katrina Millard Arlene Hurley
RU Processing Lab Irina Shimeliovich Roshni Patel Cecile Unson-O’Brien Juan P Dizon Mridushi Daga
Mount Sinai Saurabh Mehandru
Rice Lab Hans-Heinrich Hoffman Eleftherios Michailidis Casellas Lab Jena Lieberman Jianliang Xu
. Lieberman
Baric Lab Timothy Sheahan Alexandra Schaefer Sarah Leist Bowen Lan Richard Bowen