Potent immunogenicity and efficacy of a universal influenza vaccine candidate comprising a recombinant fusion protein linking influenza M2e to the TLR5 ligand flagellin.
The recognition of specific pathogen associated molecular patterns (PAMPs) by members of the Toll-like receptor (TLR) family is critical for the activation of the adaptive immune response. Thus, incorporation of PAMPs into vaccines should result in more potent, protective antigen-specific responses in the absence of adjuvants or complex formulations. Here we describe an influenza A vaccine that is refractory to the genetic instability of hemagglutinin and neuraminidase and includes a trigger of the innate immune response to enhance immunogenicity and efficacy. A recombinant protein comprising the TLR5 ligand flagellin fused to four tandem copies of the ectodomain of the conserved influenza matrix protein M2 (M2e) was expressed in Escherichia coli and purified to homogeneity. This protein, STF2.4xM2e, retained TLR5 activity and displayed the protective epitope of M2e defined by a monoclonal antibody, 14C2. Mice immunized with STF2.4xM2e in aqueous buffer, without adjuvants or other formulation additives, developed potent M2e-specific antibody responses that were quantitatively and qualitatively superior to those observed with M2e peptide delivered in alum. The antibody response was dependent on the physical linkage of the antigen to flagellin and recognized the epitope defined by monoclonal antibody 14C2, which has been shown to protect mice from challenge with influenza A virus. Moreover, immunization with STF2.4xM2e at a dose of 0.3 microg per mouse protected mice from a lethal challenge with influenza A virus, and significantly reduced weight loss and clinical symptoms. These data demonstrate that the linkage of specific TLR ligand with influenza M2e yields a vaccine candidate that offers significant promise for widespread protection against multiple influenza A virus strains.
Huleatt
James W
JW
VaxInnate Corporation, 300 George Street, New Haven, CT 06511, USA.
Nakaar
Valerian
V
Desai
Priyanka
P
Huang
Yan
Y
Hewitt
Duane
D
Jacobs
Andrea
A
Tang
Jie
J
McDonald
William
W
Song
Langzhou
L
Evans
Robert K
RK
Umlauf
Scott
S
Tussey
Lynda
L
Powell
T J
TJ
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D000939:Epitopes / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics; D005408:Flagellin / Q000235:genetics / Q000276:immunology*; D009980:Influenza A virus / Q000235:genetics; D007252:Influenza Vaccines / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D016019:Survival Analysis; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014763:Viral Matrix Proteins / Q000235:genetics / Q000276:immunology*; D015431:Weight Loss; D000086082:Viroporin Proteins
D000914:Antibodies, Viral; D000942:Antigens, Bacterial; D000956:Antigens, Viral; D000939:Epitopes; D005408:Flagellin; D007252:Influenza Vaccines; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins