Development of a live-attenuated influenza B DeltaNS1 intranasal vaccine candidate.
We discovered a unique, single amino acid mutation in the influenza B M1 protein promoting viral growth of NS1 truncation mutants in Vero cells. Due to this mutation, we were able to generate an influenza B virus lacking the complete NS1 open reading frame (DeltaNS1-B virus) by reverse genetics, which was growing to titers of 8log(10)TCID(50)/ml in a Vero cell culture-based micro-carrier fermenter. The DeltaNS1-B vaccine candidate was attenuated in IFN-competent hosts such as human alveolar epithelial cells (A549) similar to influenza A DeltaNS1 viruses. In ferrets, the DeltaNS1-B virus was replication-deficient and did not provoke any clinical symptoms. Importantly, a single intranasal immunization of ferrets at a dose as low as 6 log(10)TCID(50)/animal induced a significant HAI response and provided protection against challenge with wild-type influenza B virus. So far, the lack of a DeltaNS1-B virus component growing to high titers in cell culture has been limiting the possibility to formulate a trivalent vaccine based on deletion of the NS1 gene. Our study closes this gap and paves the way for the clinical evaluation of a seasonal, trivalent, live replication-deficient DeltaNS1 intranasal influenza vaccine.
Avir Green Hills Biotechnology, Gersthoferstrasse 29-31, 1180 Vienna, Austria.
Nina
N
Wressnigg
Daniel
D
Voss
Thorsten
T
Wolff
Julia
J
Romanova
Tanja
T
Ruthsatz
Ines
I
Mayerhofer
Manfred
M
Reiter
Sabine
S
Nakowitsch
Johannes
J
Humer
Alexander
A
Morokutti
Thomas
T
Muster
Andrej
A
Egorov
Christian
C
Kittel
D000281:Administration, Intranasal; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002522:Chlorocebus aethiops; D005289:Ferrets / Q000276:immunology; D006801:Humans; D009981:Influenza B virus / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D009154:Mutation / Q000235:genetics; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000517:prevention & control; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D014779:Virus Replication
C085820:INS1 protein, influenza virus; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D017361:Viral Nonstructural Proteins