Evoluzione genomica ed antigenica del virus della West Nile e analisi dei fattori di virulenza

Alessio Lorusso

2

• WNV, Usutu• Arboviruses• Flavivirus• Uomini, cavalli, uccelli

Flavivirus: structure

E dimer M protein

Capsid protein

Genomic RNA

Structuralproteins Non structural proteins

Genome (+ssRNA, 11000 nt)

Cap 5’

5’ 3’-OHGenomic polyprotein

C M E NS1 NS2ANS2B NS3 NS4A

NS4B NS5

Single-stranded RNA

viruses, surrounded by a

protein capsid icosahedral

symmetry with envelope.

Lineage 1a

Lineage 1b

Lineage 2

Lineage 3Lineage 4

Lineage 1: global distribution: Africa Occidentale, Medio Oriente, Est e Sud Europa, America, Australia, Asia Meridionale Lineage 2: Africa (Senegal, Uganda, R.C.A., Kenya, Madagascar) Europa

Lineage 3: Repubblica Ceca (Rabensburg virus) Lineage 4: RussiaLineage 5: India Lineage 6: strains Sarawak Kunjin virusLineage 7: African Koutango virusLineage 8: sequences in Spain

West Nile Virus Lineage

4

USUV multiple lineages

EVOLUZIONE ANTIGENICAE GENOMICA

• WNV ITALIANI 2009-2015• USUTU• CEPPI REFERENZA STORICI • JEV

• VIRUS INATTIVATI• SIERI IPERIMMUNI

USUTUJEVWNV L1WNV L2

E PROTEIN

99.4-100 % aa id tra Lin199.7-100 % aa id tra Lin293.3-95.6 % aa id tra Lin1 e Lin2 (ventina di mutazioni)76.2-78 % aa id tra WNV e USUTU (più di 100 mutazioni)

3 domains

38 WNV residues specific Abs

306, 308, 330, 366, 391conserved

• Bluetongue• African Horse Sickness

• Epizootic disease of cervids• Influenza

• Morbilliviruses!

+

STANDARDIZZAZIONE MODELLO MURINO

Survival curve, LD WNV

LD, low doseHD, high dose

competent mice

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 150

102030405060708090

100WNV Lin 1 20652WNV Lin 1 15803WNV Lin 2 20168

Time post infection

Perc

ent s

urvi

val

Survival curve, HD WNV

HD, high dose

neg