Post on 14-Jan-2016
description
transcript
Selection of CTL escape mutations is determined by both the ability to avoid CTL
recognition and by minimizing the impact on viral replicative capacity
Arne Schneidewind
Partners AIDS Research Center
Boston
HLA-B27HLA-B27
HLA-B27 restricted Epitope KK10
L268M is an early, partial escape mutation
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
R264K is the dominant escape mutation
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
R264K is accompanied by S173A
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
R264K
L268M
S173A
Replicative capacities of KK10-variants
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
Replicative capacities of KK10-variants
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
No reduction in RC for L268M
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
R264K dramatically reduces RC
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
S173A restores RC of R264K
pNL4-3 V I P M F S A L S E G // P P I P V G E I Y K R W I I L G L N K I V R M YL268M . . . . . . . . . . . // . . . . . . . . . . . . . . M . . . . . . . . .R264K . . . . . . . . . . . // . . . . . . . . . . K . . . . . . . . . . . . .S173A . . . . . A . . . . . // . . . . . . . . . . . . . . . . . . . . . . . .
265 270 275170 175 255 260
Replicative capacities of KK10-variants
Impact on replicative capacity and requirement for
compensation delays escape in B27-KK10
Replicative capacities of KK10-variants
Are there alternative ways to escape the CTL pressure against KK10?
Replicative capacities of KK10-variants
Alternative Escape Mutations in KK10
R264T
Alternative Escape Mutations in KK10
Escape Mutations in KK10 abrogate binding to HLA-B27
Alternative Escape Mutations in KK10
Replication capacity of SARKLM > than replication capacity of alternative escape mutants
Simulation of CTL pressure
Simulation of CTL pressure
Simulation of CTL pressure
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Conclusions
In VitroReplication Capacity
In Vivo Replication Capacity
Time Time
(R264T/Q/G)KTWIIL/MGLNKKQWIIL/MGLNKKGWIILGLNK
(R264K)KKWIIL/MGLNK
(WT)KRWIIL/MGLNK
(SARKLM)(SARKLM)KKKKWIIMGLNKWIIMGLNK
+ S+ S173173AA
HLA BindingVirus
strong
weak
very weak
weak Rep
licat
ion
Rep
licat
ion
Rep
licat
ion
Rep
licat
ion
Conclusions
- All CTL escape mutations at position P2 of KK10 efficiently abrogate binding to HLA-B27.
- Replicative capacity of the frequent R264K escape mutation is dramatically reduced.
- S173A efficiently compensates for the R264K replicative defect.
Conclusions
-The compensated R264K mutant (including S173A) replicated more efficiently than alternative escape mutations in the presence of KK10-specific CTL pressure.
- Replication capacities in vitro correlate well to the frequency of escape mutations in vivo.
-An in vivo threshold determines the propensity for escape variants to be selected.
AcknowledgementsPartners AIDS Research Center: California State University, San Marcos:
Mark A. Brockman Bianca R. Mothé
Yaoyu E. Wang
Huabiao Chen
Todd J. Suscovich La Jolla Institute for Allergy and Immunity:
Bin Li
Rahma I. Adam John Sidney
Rachel L. Allgaier Alessandro Sette
Thomas Kuntzen
Cesar Oniangue-Ndza
Christian Brander Funding:
Bruce D. Walker
Todd M. Allen R01-AI054178 + R21-AI067078