Limits...
Globular Head-Displayed Conserved Influenza H1 Hemagglutinin Stalk Epitopes Confer Protection against Heterologous H1N1 Virus.

Klausberger M, Tscheliessnig R, Neff S, Nachbagauer R, Wohlbold TJ, Wilde M, Palmberger D, Krammer F, Jungbauer A, Grabherr R - PLoS ONE (2016)

Bottom Line: Peptide-based vaccines have gained much interest as they allow the immune system to focus on relevant but less immunogenic epitopes.Flow cytometry and competition assays suggest that the identified stalk sequences do not recapitulate the epitopes of already described broadly neutralizing stalk antibodies.Vaccine constructs displaying 25-mer stalk sequences provided up to 75% protection from lethal heterologous virus challenge in BALB/c mice and induced antibody responses against the H1 hemagglutinin.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, Vienna, Austria.

ABSTRACT
Significant genetic variability in the head region of the influenza A hemagglutinin, the main target of current vaccines, makes it challenging to develop a long-lived seasonal influenza prophylaxis. Vaccines based on the conserved hemagglutinin stalk domain might provide broader cross-reactive immunity. However, this region of the hemagglutinin is immunosubdominant to the head region. Peptide-based vaccines have gained much interest as they allow the immune system to focus on relevant but less immunogenic epitopes. We developed a novel influenza A hemagglutinin-based display platform for H1 hemagglutinin stalk peptides that we identified in an epitope mapping assay using human immune sera and synthetic HA peptides. Flow cytometry and competition assays suggest that the identified stalk sequences do not recapitulate the epitopes of already described broadly neutralizing stalk antibodies. Vaccine constructs displaying 25-mer stalk sequences provided up to 75% protection from lethal heterologous virus challenge in BALB/c mice and induced antibody responses against the H1 hemagglutinin. The developed platform based on a vaccine antigen has the potential to be either used as stand-alone or as prime-vaccine in combination with conventional seasonal or pandemic vaccines for the amplification of stalk-based cross-reactive immunity in humans or as platform to evaluate the relevance of viral peptides/epitopes for protection against influenza virus infection.

Show MeSH

Related in: MedlinePlus

Displayed H1 stalk peptides partially protect mice from lethal heterologous H1 challenge.BALB/c mice (N = 5 per group) received a full-length HA DNA prime (i.m., 40 μg, day 0) and two truncated soluble poly(I.C)-adjuvanted HA protein booster immunizations (i.n. + i.m., 2.5 μg, day 21 and 42) of an H3 subtype HA (HIR05) carrying stalk peptides from an H1 subtype (NC99) virus engineered into its globular head: HIR05/NC99-Ep66-69 (green), HIR05/NC99-Ep86-89 (pink), HIR05/NC99-Ep69+73 (blue) or HIR05/NC99-Ep73+96 (yellow). Control mice received a DNA prime and two soluble adjuvanted protein booster immunizations with wildtype H3-subtype HIR05 HA (black) or a single vaccination with the inactivated whole virus vaccine Agriflu® intramuscularly on day 42 (grey). Three weeks later, all mice were intranasally challenged with 5 mLD50 of pandemic NL09. Weight loss (A) and survival rates (B) were monitored for 14 days post challenge. The weight loss curves represent the mean percentage of the group initial body weight and error bars indicate the standard deviation. One mouse in the study group HIR05/NC99-Ep66-69 died prior to the challenge experiment and was precluded from the calculations.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4835069&req=5

pone.0153579.g005: Displayed H1 stalk peptides partially protect mice from lethal heterologous H1 challenge.BALB/c mice (N = 5 per group) received a full-length HA DNA prime (i.m., 40 μg, day 0) and two truncated soluble poly(I.C)-adjuvanted HA protein booster immunizations (i.n. + i.m., 2.5 μg, day 21 and 42) of an H3 subtype HA (HIR05) carrying stalk peptides from an H1 subtype (NC99) virus engineered into its globular head: HIR05/NC99-Ep66-69 (green), HIR05/NC99-Ep86-89 (pink), HIR05/NC99-Ep69+73 (blue) or HIR05/NC99-Ep73+96 (yellow). Control mice received a DNA prime and two soluble adjuvanted protein booster immunizations with wildtype H3-subtype HIR05 HA (black) or a single vaccination with the inactivated whole virus vaccine Agriflu® intramuscularly on day 42 (grey). Three weeks later, all mice were intranasally challenged with 5 mLD50 of pandemic NL09. Weight loss (A) and survival rates (B) were monitored for 14 days post challenge. The weight loss curves represent the mean percentage of the group initial body weight and error bars indicate the standard deviation. One mouse in the study group HIR05/NC99-Ep66-69 died prior to the challenge experiment and was precluded from the calculations.

Mentions: As we wanted to assess the ability of displayed NC99-derived H1 HA stalk peptides to confer homosubtypic cross-protection they were tested against a lethal 5 mLD50 dose of an unmatched heterologous pandemic NL09 challenge virus. Strikingly, the carrier HA displaying a 25-mer spanning the HA intersubunit region (HIR05/NC99-Ep66-69) was sufficient to protect three out of four mice (75%; p = 0.0171) from mortality in the lethal heterologous challenge experiment (Fig 5B). One mouse in this study group died prior to the challenge experiment and was precluded from further calculations. This group also experienced weight-loss kinetics comparable to the positive control group until day 6 post challenge (Fig 5A). Additionally, one out of five mice (20%; non-significant) immunized with an HA-displayed peptide from the long alpha-helix (HIR05/NC99-Ep86-89) was protected from the lethal challenge. Mice immunized with the two HA-carriers displaying putative discontinuous epitopes (HIR05/NC99-Ep69+73 or HIR05/NC99-Ep73+96) and the negative control group (HIR05) all succumbed to infection between day 7 and day 9 post challenge (Fig 5B). None of the study groups, however, were protected from morbidity, reflected by weight-loss until day 8 or 9 (Fig 5A).


Globular Head-Displayed Conserved Influenza H1 Hemagglutinin Stalk Epitopes Confer Protection against Heterologous H1N1 Virus.

Klausberger M, Tscheliessnig R, Neff S, Nachbagauer R, Wohlbold TJ, Wilde M, Palmberger D, Krammer F, Jungbauer A, Grabherr R - PLoS ONE (2016)

Displayed H1 stalk peptides partially protect mice from lethal heterologous H1 challenge.BALB/c mice (N = 5 per group) received a full-length HA DNA prime (i.m., 40 μg, day 0) and two truncated soluble poly(I.C)-adjuvanted HA protein booster immunizations (i.n. + i.m., 2.5 μg, day 21 and 42) of an H3 subtype HA (HIR05) carrying stalk peptides from an H1 subtype (NC99) virus engineered into its globular head: HIR05/NC99-Ep66-69 (green), HIR05/NC99-Ep86-89 (pink), HIR05/NC99-Ep69+73 (blue) or HIR05/NC99-Ep73+96 (yellow). Control mice received a DNA prime and two soluble adjuvanted protein booster immunizations with wildtype H3-subtype HIR05 HA (black) or a single vaccination with the inactivated whole virus vaccine Agriflu® intramuscularly on day 42 (grey). Three weeks later, all mice were intranasally challenged with 5 mLD50 of pandemic NL09. Weight loss (A) and survival rates (B) were monitored for 14 days post challenge. The weight loss curves represent the mean percentage of the group initial body weight and error bars indicate the standard deviation. One mouse in the study group HIR05/NC99-Ep66-69 died prior to the challenge experiment and was precluded from the calculations.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835069&req=5

pone.0153579.g005: Displayed H1 stalk peptides partially protect mice from lethal heterologous H1 challenge.BALB/c mice (N = 5 per group) received a full-length HA DNA prime (i.m., 40 μg, day 0) and two truncated soluble poly(I.C)-adjuvanted HA protein booster immunizations (i.n. + i.m., 2.5 μg, day 21 and 42) of an H3 subtype HA (HIR05) carrying stalk peptides from an H1 subtype (NC99) virus engineered into its globular head: HIR05/NC99-Ep66-69 (green), HIR05/NC99-Ep86-89 (pink), HIR05/NC99-Ep69+73 (blue) or HIR05/NC99-Ep73+96 (yellow). Control mice received a DNA prime and two soluble adjuvanted protein booster immunizations with wildtype H3-subtype HIR05 HA (black) or a single vaccination with the inactivated whole virus vaccine Agriflu® intramuscularly on day 42 (grey). Three weeks later, all mice were intranasally challenged with 5 mLD50 of pandemic NL09. Weight loss (A) and survival rates (B) were monitored for 14 days post challenge. The weight loss curves represent the mean percentage of the group initial body weight and error bars indicate the standard deviation. One mouse in the study group HIR05/NC99-Ep66-69 died prior to the challenge experiment and was precluded from the calculations.
Mentions: As we wanted to assess the ability of displayed NC99-derived H1 HA stalk peptides to confer homosubtypic cross-protection they were tested against a lethal 5 mLD50 dose of an unmatched heterologous pandemic NL09 challenge virus. Strikingly, the carrier HA displaying a 25-mer spanning the HA intersubunit region (HIR05/NC99-Ep66-69) was sufficient to protect three out of four mice (75%; p = 0.0171) from mortality in the lethal heterologous challenge experiment (Fig 5B). One mouse in this study group died prior to the challenge experiment and was precluded from further calculations. This group also experienced weight-loss kinetics comparable to the positive control group until day 6 post challenge (Fig 5A). Additionally, one out of five mice (20%; non-significant) immunized with an HA-displayed peptide from the long alpha-helix (HIR05/NC99-Ep86-89) was protected from the lethal challenge. Mice immunized with the two HA-carriers displaying putative discontinuous epitopes (HIR05/NC99-Ep69+73 or HIR05/NC99-Ep73+96) and the negative control group (HIR05) all succumbed to infection between day 7 and day 9 post challenge (Fig 5B). None of the study groups, however, were protected from morbidity, reflected by weight-loss until day 8 or 9 (Fig 5A).

Bottom Line: Peptide-based vaccines have gained much interest as they allow the immune system to focus on relevant but less immunogenic epitopes.Flow cytometry and competition assays suggest that the identified stalk sequences do not recapitulate the epitopes of already described broadly neutralizing stalk antibodies.Vaccine constructs displaying 25-mer stalk sequences provided up to 75% protection from lethal heterologous virus challenge in BALB/c mice and induced antibody responses against the H1 hemagglutinin.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, Vienna, Austria.

ABSTRACT
Significant genetic variability in the head region of the influenza A hemagglutinin, the main target of current vaccines, makes it challenging to develop a long-lived seasonal influenza prophylaxis. Vaccines based on the conserved hemagglutinin stalk domain might provide broader cross-reactive immunity. However, this region of the hemagglutinin is immunosubdominant to the head region. Peptide-based vaccines have gained much interest as they allow the immune system to focus on relevant but less immunogenic epitopes. We developed a novel influenza A hemagglutinin-based display platform for H1 hemagglutinin stalk peptides that we identified in an epitope mapping assay using human immune sera and synthetic HA peptides. Flow cytometry and competition assays suggest that the identified stalk sequences do not recapitulate the epitopes of already described broadly neutralizing stalk antibodies. Vaccine constructs displaying 25-mer stalk sequences provided up to 75% protection from lethal heterologous virus challenge in BALB/c mice and induced antibody responses against the H1 hemagglutinin. The developed platform based on a vaccine antigen has the potential to be either used as stand-alone or as prime-vaccine in combination with conventional seasonal or pandemic vaccines for the amplification of stalk-based cross-reactive immunity in humans or as platform to evaluate the relevance of viral peptides/epitopes for protection against influenza virus infection.

Show MeSH
Related in: MedlinePlus