Hatada, M

Matsushita, S

Narahara, C

Shigeyoshi, H

Yoshimura, K

Retrovirology

English

PubMed

C Narahara

M Hatada

H Shigeyoshi

K Yoshimura

S Matsushita

Springer - Publisher Connector

BioMed Central
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Retrovirology
Open AccessPoster presentation
P09-16. A primary R5 isolate undergoes different escape pathway 
during in vitro selection with low or high concentration of an anti-V3 
monoclonal antibody
C Narahara*, M Hatada, H Shigeyoshi, K Yoshimura and S Matsushita
Address: Clinical Retrovirology and Infectious Diseases, Center for AIDS Research, Kumamoto University, Kumamoto, Japan
* Corresponding author    
Background
The mechanisms of immune escape from neutralizing
antibody are not fully understood for primary HIV-1 iso-
lates with R5 phenotype. Using two different conditions
of the anti-V3 humanized monoclonal antibody (MAb)
KD-247 for selecting escape mutants we analyzed the
mechanism of escape pathway of a primary R5 virus.
Methods
We induced escape variants by exposing a neutralization-
sensitive primary R5 isolate, HIV-1MTA to increasing con-
centrations of KD-247 in PM1/CCR5 cells. The virus was
initially exposed 1 or 0.05 μg/ml of KD-247 and was seri-
ally passaged up to 1000 μg/ml. We determined the
changes in the amino acid (aa) sequences of gp120-
encoding region at each passage and monitored neutrali-
zation sensitivity of the passaged virus by WST-8 assay. To
compare replication fitness of the escape mutants a com-
petition assay was performed in the presence or absence of
KD-247.
Results
Under high KD-247 pressure (1 μg/ml), a substitution of
aa in V3 tip (GPGR→GQGR, MTAP313Q) was observed at
passage 2 (p2) and was subsequently detected in virtually
all the clones examined at p5 (20 μg/ml). On the other
hand, under relatively low KD-247 pressure (0.05 μg/ml),
another substitution in V3 tip (GPGR→GPGK, MTAR315K)
was emerged at p5 (0.4 μg/ml) and was dominated in vir-
tually all subsequent clones at p14 (10 μg/ml). These
escape mutants were found to have highly resistant phe-
notype to KD-247. A series of competition assay of the
mutants revealed that MTAR315K replicates better than
MTAP313Q in the absence of KD-247. On the other hand,
MTAP313Q dominated over MTAR315K in the presence of
KD-247.
Conclusion
The viral fitness to the cell and the resistance to the spe-
cific antibodies are major factors contributing the virus
escape from neutralizing antibodies. Our results demon-
strated the primary R5 isolate HIV-1MTA underwent differ-
ent escape pathway dependent on the concentration of
the antibody.
from AIDS Vaccine 2009
Paris, France. 19–22 October 2009
Published: 22 October 2009
Retrovirology 2009, 6(Suppl 3):P129 doi:10.1186/1742-4690-6-S3-P129
<supplement> <title> <p>AIDS Vaccine 2009</p> </title> <editor>Anna Laura Ross</editor> <note>Meeting abstracts – A single PDF containing all abstracts in this Supplement is available <a href="http://www.biomedcentral.com/content/files/pdf/1742-4690-6-S3-full.pdf">here</a>.</note> <url>http://www.biomedcentral.com/content/pdf/1471-2105-10-S12-info.pdf</url> </supplement>
This abstract is available from: http://www.retrovirology.com/content/6/S3/P129
© 2009 Narahara et al; licensee BioMed Central Ltd. 


P09-16. A primary R5 isolate undergoes different escape pathway during in vitro selection with low or high concentration of an anti-V3 monoclonal antibody

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P09-16. A primary R5 isolate undergoes different escape pathway during in vitro selection with low or high concentration of an anti-V3 monoclonal antibody

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