Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range...

46
Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität Marburg Summer School on Influenza Siena, August 1-5, 2011

Transcript of Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range...

Page 1: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Determinants of

Pathogenicity and Host

Range of Influenza Viruses

Hans Dieter Klenk

Institut für Virologie

Philipps Universität Marburg

Summer School on Influenza

Siena, August 1-5, 2011

Page 2: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Emerging Infections: Zoonoses

Virus Disease Year Natural Host

Influenza A Virus Spanish Influenza 1918 Birds

Asian Influenza 1957

Hongkong Influenza 1968

Mexican Influenza 2009

„Bird Flu“ 1997

Marburg Virus Hemorrhagic Fever 1967 Bats

Ebola Virus Hemorrhagic Fever 1976 Bats

HIV AIDS 1981 Apes

Hendra Virus Encephalitis 1994 Bats

Nipah Virus Encephalitis 1996 Bats

Sin Nombre Virus Hemorrhagic Fever 1993 Mice

SARS Coronavirus SARS 2002 Bats

Page 3: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Man (Marburg-Virus)

ManMan

AnimalAnimal

Zoonoses: 2 types

(Influenza-Virus)

Page 4: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Zoonoses

Type 1 High case-fatality rate (< 100%)Local and temporal restriction of outbreaksRestricted human to human transmissionVirus does not adapt to man

Type 2 High case numbersPandemic spreadHuman to human transmissionVirus adapts to man

Page 5: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Discovery of Influenza-Viruses

W.S. Smith, C.H. Andrewes, P.P. Laidlaw

1901E. Centanni

1955W. Schäfer

1931R.E. Shope

1933

human

avianporcine

Influenza – a Zoonosis

Page 6: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Influenza – a zoonosisMajor natural reservoir of influenza viruses: feral aquatic birds

Contains many viruses defined by 16 HA and 9 NA subtypes

Order Anseriformes (waterfowl) (ducks, geese and swans)

Order Charadriiformes (shorebirds and gulls)

Page 7: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

- Occasional transmissions with

outbreaks of various severity

- Transmission may involve

intermediate host

- On rare occasions, adaptation to

new species and establishing of

stable virus lineages

- Transmission to humans of

antigenically new virus can initiate

pandemic

Interspecies transmission of influenza viruses

H3

H7

H1

H1´

H3

H5

H6

H7

H9

H1

H2

H3

B ?

H3

H4

H13

Page 8: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Pathogenicity of Influenza A Viruses

Human Influenza Avian Influenza

E. Munch

Self portrait

1918

Respiratory infection

Enteric Infection

Pathogenic

(H5, H7)

Apathogenic

(H1-H16)

Fowl Plague

Page 9: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

1900 1910 1920 1930 1940 1950 1960 19801970 1990 2000 2010

A/H1N1

A/H2N2

A/H5N1

A/H1N1

A/H3N2

A/H1N1

Human Influenza A Outbreaks

Page 10: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

The Impact of the Spanish Influenza 1918

20-40 million deaths worldwide

70

60

50

40

30

1900 „30 „50 „70 „90

U.S. Life ExpectancyBy age

Page 11: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Influenza H5N1 virus causes severe multisystem disease in chickens and humans

• pneumonia

• severe systemic infection

• diarrhoea

• Encephalitis

• Lymphopenia, thrombocytopeni, hypoglycaemia

• death

05/02/04 10/02/04

Jeremy Farrar, Oxford, HCMC

Page 12: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

1900 1910 1920 1930 1940 1950 1960 19801970 1990 2000 2010

?1946

“non-pandemic”

19571977

Brisbane/59/2007

Human

Classical swine

Fort Dix

Human H3N2

avian

Triple reassortant

Eurasian swine

avian

1918 Pandemic

Human and swine H1N1 viruses

New H1N1

Page 13: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Pig – the mixing vessel

C. Scholtissek, 1990

Wilhelm Busch, 1832-1908

Page 14: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

H1N1 Pandemic 2009, Europe

Deaths 500 – 4.000

ARDS-cases 5000 – 75.000

ECDC, Jan. 2010

Page 15: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

ARDS/H1N1v Patients UKGM Nov. 2009 – Jan. 2010

Patient Sex Age Comorbidity Coinfection IC Influenza- Course

Treatment therapy

I.N. w 21 - - Ventilation Oseltamivir Discharged

K.C. m 40 - - ECMO Oseltamivir Discharged

K.G. w 56 ? - ECMO Oseltamivir

S.M. m 53 cor. sclero. - ECMO Zanamivir. Discharged

A.O. m 51 Lung fibrosis Klebsiella ECMO Zanamivir Lungtranspl.

H.K. w 52 - Klebs./HSV1 ECMO Zanamivir Discharged

M. Sch.w 19 - - ECMO Zanamivir Discharged

M. St. m 21 - Candida ECMO Zanamivir Discharged

A. A. m 45 - mdr. Pseudom. ECMO Zanamivir

L. M. w 30 - - ECMO Zanamivir Discharged

T. S. w 39 - - ECMO Zanamivir Discharged

V. E. m 39 - HSV1 ECMO Zanamivir Discharged

J. E. w 25 - - ECMO Zanamivir Discharged

Courtesy: S. Herold, Gießen – C. Aepinus,

Marburg

Page 16: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Extra-Corporal Membrane Oxygenation

Uniklinik Gießen, Jan 2010

H1N1v

Page 17: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

HA

NA

M1

PB1

PB2

PA

NS2

NP

M2

NS1

PB1 F2

Orthomyxoviridae

Segmented, negative stranded RNA

genome

Influenza A Virus

Page 18: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

RNP, M1

mRNA

Budding

Endocytosis

Fusion

Translation and processing

of envelope proteins

Translation of

internal proteins

Insertion of envelope proteins

into plasmamembrane

mRNA synthesis

RNA replication

RNP formation

Receptor binding

Life Cycle of Influenza Virus

Neuraminic acid

Page 19: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

The Polymerase

- Role in Host Adaptation -

Page 20: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Gabriel et al., PNAS 2005

Gabriel et al., J Virol 2007

NPPB1 PB2

PA

Adaptation to Mice is Mediated

by Mutations in the

Polymerase Complex

Host

factors

Host

factors

Host

factors

Host

factors

Adaptation of an Avian Influenza Virus to a Mammalian Host

SC35H7N7

SC35MH7N7

Page 21: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

SC35-PB2

NLS

D701 NLSD701

Importin a1

SC35M-PB2

Importin a1

NLS

N701

Cytoplasm Nucleus

NLSN

701

SC35-PB2

Importin a1

SC35M-PB2

Importin a1

Cytoplasm Nucleus

NLS NLS

NLS NLS

Differential interaction with importin a regulates nuclear import of PB2

Mammalian Cells Avian Cells

Gabriel et al., PLoS Pathogens, 2008

Page 22: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Effects of Importin-α Knockout and Silencing on Replication and Pathogenicity

Differential Use of Importin- α Isoforms Governs Cell Tropism and Host Adaptation of Influenza Viruses

α1 α3 α4 α5 α7

SC 35 = = =

SC 35 M = = =

A/FPV/Rostock/1/34 (H7N1) = = =

A/Thai/KAN-1/04 (H5N1) (human iso.) = = =

A/Victoria/3/75 (H3N2) = = =

A/Sachsen-Anhalt/101/09 (H1N1 pdm) = =

Gabriel et al., Nature Com., 2011

Page 23: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Compartment Borders are Favorite Cellular Sites for Adaptation Processes

Neuraminic acid

RNP, M1

mRNA

Budding

Endocytosis

Fusion

Translation and processing

of envelope proteins

Translation of

internal proteins

Insertion of envelope proteins

into plasmamembrane

mRNA synthesis

RNA replication

RNP formation

Receptor binding

- Receptor Binding of HA at Plasma Membrane

- Importin Binding of Pol at Nuclear Envelope

Conclusion

Page 24: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

PB1 PB2 PA NP Adaptive mutations ---------- ------------------------------------ --------- ----------- (avian-mammalian) L13P E627K D701N S714R(I) K615R N319K 2009 A(H1N1) 13P E627 D701 S714 K615 N319

Host Range Markers of New Influenza A (H1N1) Polymerase

Determinants for avian specificity have been preserved

Page 25: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Adaptive PB2 mutations increase polymerase

activity of A/Hamburg/05/2009 (H1N1)

10

100

397

335 293

627

761

565

906

0

200

400

600

800

1000

1200

moc

kW

T62

770

171

4

627-

701

627-

714

701-

714

Tripel

rela

tive a

cti

vit

y (

%)

Page 26: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

0

20

40

60

80

100

120

0 2 4 6 8 10 12 14

we

igh

t lo

ss

[%

]

days p.i.

PBS

H1N1v

H1N1v-PB2-E627K

H1N1v-PB2-D701N

H1N1v-PB2-S714I

H1N1v-PB2-E627K-D701N

H1N1v-PB2-E627K-S714I

H1N1v-PB2-D701N-S714I

0

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

su

rviv

al [%

]

days p.i.

PBS

H1N1v

H1N1v-PB2-E627K

H1N1v-PB2-D701N

H1N1v-PB2-S714I

H1N1v-PB2-E627K-D701N

H1N1v-PB2-E627K-S714I

H1N1v-PB2-D701N-S714I

Mouse pathogenicity of PB2 mutants of H1N1v

Page 27: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Summary

- The influenza virus polymerase is an important determinant

of host range, tissue tropism and pathogenicity

- Interspecies transmission depends on adaptation of

polymerase subunits to importin-α

- The H1N1v polymerase has retained genetic markers of

avian viruses

- Introduction of mammalian markers enhances

pathogenicity for mice

- The pathogenetic and pandemic potential of H1N1v may

not be exhausted yet

Page 28: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Effector DomainRBD

20 41 108 110 126 217

ISG-15 K

Effector DomainRBD

217219

SUMO1 K

221

ISG-15 NS1 SUMO-1

Importin a binding and nuclear

transport of NS1 disrupted

Dimerization of NS1 impaired

Virus replication reduced

Chen et al., PNAS 2010

Tang et al., J. Immunol. 2010

Stability of NS1 enhanced

Virus replication enhanced

Xu et al., J. Virol. 85, 1086-1098 (2011)

ISG-15ylation and SUMOylation of NS1

219

Page 29: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

C.

Strain dependent SUMOylation of

NS1

A, B: Truncated C-terminus of NS1 of 2009 pdm H1N1 is not SUMOylated

C: C-Terminal elongation does not restore SUMOylation

(De)-SUMOylation of NS1: Effect on Pathogenicity of 2009 pdm H1N1?

Page 30: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

The Hemagglutinin

- Role in Pathogenesis and Host Specificity -

Page 31: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

The Cleavage Site of HA Determines the Pathogenicity of Avian Influenza Viruses

R

H1-H16

R

X

K/R

apathogenic

virus

pathogenic

virus

local

infection

systemic

infection

trypsin-

like proteasefurin

R

H5, H7

Klenk et al., Virology 1975 Kawaoka and Webster, PNAS 1988

Bosch et al., Virology 1981 Stieneke-Gröber et al., EMBO J. 1992

Garten et al., Virology 1981 Böttcher et al., J. Virol. 2006

Page 32: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Serine Proteases HAT and TMPRSS2

TMPRSS2 (Transmembrane protease, serine S1 family member 2)

HAT (Human airway trypsin-like protease)

-CH D SSRCRLDLRAN- TM

S - S

H D SN- SEA

S - S

-CTM

Trypsin-like substrate specificity

Expression in human airways

(HAT: predominantely trachea; TMPRSS2: nasal cavity, trachea, bronchi, lung)

Type II transmembrane serine proteases

Synthesized as zymogens, autocatalytic activation

Physiological role in the airway epithelium remains to be determined

Page 33: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

TMPRSS2

HAT

??

Subcellular localization of HA cleavage

HAT cleaves HA at the cell surface

TMPRSS2 cleaves HA intracellularly

HAT activates newly synthesized HA and

HA of incoming virus

TMPRSS2 cleaves newly synthesized HA

but is not capable to activate HA of

incoming virus

Cleavage of HA by TMPRSS2 and HAT

differs in subcellular localisation and can

take place at different steps of viral

replication:

Page 34: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

nicht

infiziert

S. aureusInfluenzavirus

S. aureus

Influenzavirus

Bakterielle Protease und Influenzapneumonie

Tashiro et al., Nature 1987

Page 35: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Inhibition of Viral Spread of A/Hamburg/5/2009 (H1N1) by Peptidomimetics

I-1: Bzls-dArg-Pro-4-amidinobenzylamid

I-2: Bzls-dCha-Pro-4-amidinobenzylamid

I-3: Bzls-dCha-Lys(Dec)-4-amidinobenzylamid

Bzls = Benzylsulfonyl

Cha = Cyclohexylalanin

Dec = decanoyl

- + + + + Dox

I-1 I-2 I-3

A/H

am

bu

rg/0

9V

SV

MDCK-

HAT

MDCK-

TMPRSS2

MDCK-

TMPRSS2

Inhibitor

Böttcher-Friebertshäuser et al. (2010), J Virol

S

HN

O O

N

O

NH

NH2HN

O HN NH2

NH

S

HN

O O

N

OO H

N NH2

NH

S

HN

O O

NH

OO H

N NH2

NH

NH

O

CH38

I-2

I-3

I-1

Viral spread in HAT-expressing cells suppressed by

all applied inhibitors

Inhibition of viral spread in TMPRSS2-expressing

cells seems to require cellular uptake of the inhibitor

Page 36: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Virus spread in MDCK cells is retarded and reduced to ~300 fold by inhibitors

R

10µM 25µM 50µM Ø

MI-0299

MI-0701

MI-0702

Inhibitor

Lu, Steinmetzer & Garten, unpublished

5x107 1,5 x106 4,5 x108

MI-299 MI-701

PFU/ml

Plaque reduction test

Influenzavirus A/chick/Rostock/ 34 (H7N1)

Inhibitors

No inhibitor

control

FPV

Spread

immuno-

Stained

18 h p.i.

Time (hrs)

Δ

10

30

50

120

0 10 20 30 40 50 60 70

Δ

ΔΔ

Re

lea

se

d v

iru

s p

art

icle

s

MI-299

MI-701

w/o

HAU

25µM

Inhibition of Fowl Plague Virus (FPV) Replication by Peptidomimetics

Page 37: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Generation of Vaccine Strains by Genetic Manipulation of HA Cleavage Site

Decreasing pathogenicity

Inactivated vaccines

(pandemic H5N1 vaccine)

Stech et al.,

Nature Medicine,

2005

R

trypsin-like

protease

RX

K/RR

furin

Live vaccines

R

trypsin-like

protease

V

elastase

RX

K/RR

furin

V

elastaseGabriel et al.

Vaccine 2008

R

R

Page 38: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Receptor specificity of H1N1v

Page 39: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

HA polymorphism in position 222 (225, H3 numb.)

- Major variant, 222D. Substitutions G,E,N.

- 222G found in 7-10% of sequences in fatal and severe cases, but not in

clinically mild cases. The mutants seem to occur sporadically with no

evidence of sustained transmission.

- 222E – No apparent correlation with disease severity; transmissible

virus.

- 222N – Not enough data.

Page 40: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Amino acid 222

- Correlates with the virus host species. Avian viruses have 222G, human and

swine viruses have 222D/E. Propagation of human viruses in hen‟s eggs often

leads to mutations D222G/N.

- Mutation D222G increases binding to 3-linked receptors of human viruses

(Gambaryan et al., 1997,1999; Glaser et al., 2005; Stevens et al., 2006), including

H1N1pdm (Yang, Carney & Stevens, PLoS Curr Influenza 2010).

- Mutation D222G decreased airborne transmission of the 1918 virus in ferrets

(Tumpey et al., 2007).

Page 41: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Can mutations D222G/E in H1N1pdm

change viral cell tropism and replication

efficiency in human respiratory tract ?

Page 42: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Human and avian viruses target different types of

cells

Seasonal human virus Avian virus

<5 % of infected ciliated cells >70

Page 43: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Cell tropism of H1N1pdm in HTBE cultures

222D: 222G:

Moldova/G186/09, Cyprus/S2487/09 Lviv/N6/09 (fatal),

Hamburg/5/09 Norway/3206-3/09 (fatal)

222E: Hamburg/5/09-e (egg-derived)

Dakar/37/09

3-5 % of infected ciliated cells 20-30

Page 44: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

Receptor specificity, glycoarraysD222G mutation increases binding to 3-linked Sia

2-6

2-3

2-6

2-3

Page 45: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

- Mutation D222G alters receptor specificity

and cell tropism of H1N1v in human

respiratory epithelium

- Mutation D222G may cause (or reflect

severe disease resulting form H1N1v

replication in the LRT (Shinya et al., 2006; van Riel et al., 2007; Nell et al, 2010)

- Position 222 mutants and other mutations

with altered receptor specificity have to be

closely monitored

Conclusions

Page 46: Determinants of Pathogenicity and Host Range of … · Determinants of Pathogenicity and Host Range of Influenza Viruses Hans Dieter Klenk Institut für Virologie Philipps Universität

ACKNOWLEDGEMENTS

University of Tokushima

Hiroshi Kido

Yuushi Okumura

Universität Marburg

Joanna Baron

Volker Czudai

Björn Keiner

Folker Schwalm

Wolfgang Garten

Eva Böttcher-Friebertshäuser

Catharina Freuer

Carolin Tarnow

Mikhail Matrosovich

Tatyana Matrosovich

Jennifer Uhlendorff

Stephan Becker

Markus Eickmann

Torsten Steinmetzer

Heinrich Pette Institut Hamburg

Gülsah Gabriel

Kawasaki Medical

School

Masanobu Ohuchi

Imperial College

London

Ten Feizi

Yan Lin

Robert A. Childs

MRC NIMR Mill Hill

Alan Hay

Stephen Warton

Rodney Daniels

Deutsche

Forschungsgemeinschaft

SFB 593, SPP 1190

European Commission

STREP FLUPOL

Pasteur Institute Shanghai

Ke Xu

Bing Sun

Universität Würzburg

Christoph Klenk

University of Oxford

George Brownlee

Ervin Fodor