Generation and Characterization of Recombinant Pandemic Influenza

A/H1N1 Viruses Resistant to Neuraminidase Inhibitors

Andrés Pizzorno, Xavier Bouhy, Yacine Abed, Guy Boivin

Research Center in Infectious Diseases of the CHUL, Québec, QC, Canada

PCIRN Annual MeetingApril 20 - 21, 2011

Results – Resistance to NAIs

NAVariant

WT E119V E119G D198G H274Y N294S I222V S334N I222VH274Y

H274Y S334N

OSELT IC50

nM ± sd

0,46 ± 0,01

R(60,2)

SR

(16,8)R

(982)R

(208)I S

R(1733)

R(658)

ZANAM IC50

nM ± sd

0,15 ± 0,01

R(571)

R(832)

I S S S S S S

PERAMIC50

nM ± sd

0,09 ± 0,01

R(25,3)

R(51,2)

SR

(263)R

(12)S S

R(1331)

R(178)

A315675IC50

nM ± sd

0,20± 0,03

R(69)

R(123)

S S S S S S S

Substitutions at E119 confer multi-drug resistance

Synergic effect of I222V on H274Y resistant phenotype

S=sensitive: <5 IC50 fold increase, I=intermediate: 5 to 10 IC50 fold increase, R=resistant: >10 IC50 fold increase

(Mutations in N2 numbering)

Results – Replicative capacity in vitro

* P<0.05, ** P<0.01

E119G/V have a negative effect on viral fitness

I222V can be associated with improved viral fitness

Results – In vivo transmission

Contact

Aerosol Aerosol

ContactInoculated Inoculated

Efficient contact and aerosol transmission in the ferret model

No differences in transmission rates among the WT and mutants