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Recombinant trimeric HA protein immunogenicity of H5N1 avian influenza viruses and their combined use with inactivated or adenovirus vaccines.

Lin SC, Huang MH, Tsou PC, Huang LM, Chong P, Wu SC - PLoS ONE (2011)

Bottom Line: The hemagglutinin (HA) envelope protein is the primary target for subunit vaccine development.We investigated trimeric rHA protein immunogenicity in mice via immunizations, and found that the highest levels of neutralizing antibodies resulted from coupling with a PELC/CpG adjuvant.We also found that the combined use of trimeric rHA proteins with (a) an inactivated H5N1 vaccine virus, or (b) a recombinant adenovirus encoding full-length HA sequences for prime-boost immunization, further improved antibody responses against homologous and heterologous H5N1 virus strains.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biotechnology and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan.

ABSTRACT

Background: The highly pathogenic avian influenza (HPAI) H5N1 virus continues to cause disease in poultry and humans. The hemagglutinin (HA) envelope protein is the primary target for subunit vaccine development.

Methodology/principal findings: We used baculovirus-insect cell expression to obtain trimeric recombinant HA (rHA) proteins from two HPAI H5N1 viruses. We investigated trimeric rHA protein immunogenicity in mice via immunizations, and found that the highest levels of neutralizing antibodies resulted from coupling with a PELC/CpG adjuvant. We also found that the combined use of trimeric rHA proteins with (a) an inactivated H5N1 vaccine virus, or (b) a recombinant adenovirus encoding full-length HA sequences for prime-boost immunization, further improved antibody responses against homologous and heterologous H5N1 virus strains. Data from cross-clade prime-boost immunization regimens indicate that sequential immunization with different clade HA antigens increased antibody responses in terms of total IgG level and neutralizing antibody titers.

Conclusion/significance: Our findings suggest that the use of trimeric rHA in prime-boost vaccine regimens represents an alternative strategy for recombinant H5N1 vaccine development.

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Related in: MedlinePlus

Neutralization against H5 pseudotyped particles in mice receiving combined immunizations.Neutralizing antibody titers in sera were determined using KAN-1 pseudotyped viruses (A, dose-dependent neutralization curves; C, ID50). For neutralization against the KAN-1 strain, mice immunized with NIBRG-14 or rAd (KAN-1) followed by HA (Anhui) had the highest levels of neutralization antibodies; mice immunized with HA (Anhui) followed by NIBRG-14 had the lowest. For neutralization against the Anhui strain (B, dose-dependent neutralization curves; D, ID50), mice immunized with Anhui rAd followed by KAN-1 HA had the highest levels of neutralization antibodies, and mice immunized with two doses of NIBRG-14 had the lowest. Asterisk (*) indicates a statistically significant difference compared to the double-dose of inactivated NIBRG-14 group (p<0.05, Student t test). Triangle (▽) indicates a statistically significant difference compared to other immunized groups (p<0.05, Student t test).
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pone-0020052-g007: Neutralization against H5 pseudotyped particles in mice receiving combined immunizations.Neutralizing antibody titers in sera were determined using KAN-1 pseudotyped viruses (A, dose-dependent neutralization curves; C, ID50). For neutralization against the KAN-1 strain, mice immunized with NIBRG-14 or rAd (KAN-1) followed by HA (Anhui) had the highest levels of neutralization antibodies; mice immunized with HA (Anhui) followed by NIBRG-14 had the lowest. For neutralization against the Anhui strain (B, dose-dependent neutralization curves; D, ID50), mice immunized with Anhui rAd followed by KAN-1 HA had the highest levels of neutralization antibodies, and mice immunized with two doses of NIBRG-14 had the lowest. Asterisk (*) indicates a statistically significant difference compared to the double-dose of inactivated NIBRG-14 group (p<0.05, Student t test). Triangle (▽) indicates a statistically significant difference compared to other immunized groups (p<0.05, Student t test).

Mentions: Neutralization H5pp assays were used to determine neutralizing antibody titers elicited by the use of trimeric rHA proteins in combination with inactivated NIBRG-14 or rAd-HA versus dual-dose NIBRG-14 virus immunizations. According to our results, all of these prime-boost immunization combinations induced dose-independent neutralizing antibody responses against KAN-1 (Fig. 7A) and Anhui (Fig. 7B). The ID-50 values were higher for the inactivated NIBRG-14 virus plus trimeric rHA protein booster than for the two-dose inactivated NIBRG-14 virus immunization against the same or different H5N1 HA clade (Figs. 7C–D). An Anhui rHA protein booster induced more neutralizing antibody titers than a KAN-1 rHA protein booster following inactivated NIBRG-14 virus priming, but the difference was not statistically significant. Compared to two-dose inactivated NIBRG-14 virus immunization, priming with KAN-1 or Anhui rHA protein plus an inactivated NIBRG-14 virus booster resulted in either a slower increase or outright reduction of neutralizing antibody titers against both the homologous (clade 1) and heterologous (clade 2.3.4) strains of H5N1 viruses. Priming with KAN-1 rAd-HA followed by an Anhui rHA protein booster resulted in the highest ID50 values against KAN-1, but the difference was not statistically significant compared to two-dose inactivated NIBRG-14 virus immunization (Fig. 7C). Priming with either rAd-HA (KAN-1 or Anhui) followed by a booster with KAN-1 or Anhui rHA protein elicited stronger neutralizing antibody responses against the H5N1 Anhui clade (2.3.4) than two doses of inactivated NIBRG-14 (Fig. 7D). Priming with Anhui rAd-HA followed by a KAN-1 rHA protein booster resulted in the highest ID50 values against Anhui (Fig. 7D). The use of different HA antigen clades in adenovirus vector-primed and recombinant protein booster immunizations further enhanced neutralizing antibody responses to homologous and heterologous H5N1 virus strains.


Recombinant trimeric HA protein immunogenicity of H5N1 avian influenza viruses and their combined use with inactivated or adenovirus vaccines.

Lin SC, Huang MH, Tsou PC, Huang LM, Chong P, Wu SC - PLoS ONE (2011)

Neutralization against H5 pseudotyped particles in mice receiving combined immunizations.Neutralizing antibody titers in sera were determined using KAN-1 pseudotyped viruses (A, dose-dependent neutralization curves; C, ID50). For neutralization against the KAN-1 strain, mice immunized with NIBRG-14 or rAd (KAN-1) followed by HA (Anhui) had the highest levels of neutralization antibodies; mice immunized with HA (Anhui) followed by NIBRG-14 had the lowest. For neutralization against the Anhui strain (B, dose-dependent neutralization curves; D, ID50), mice immunized with Anhui rAd followed by KAN-1 HA had the highest levels of neutralization antibodies, and mice immunized with two doses of NIBRG-14 had the lowest. Asterisk (*) indicates a statistically significant difference compared to the double-dose of inactivated NIBRG-14 group (p<0.05, Student t test). Triangle (▽) indicates a statistically significant difference compared to other immunized groups (p<0.05, Student t test).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3104987&req=5

pone-0020052-g007: Neutralization against H5 pseudotyped particles in mice receiving combined immunizations.Neutralizing antibody titers in sera were determined using KAN-1 pseudotyped viruses (A, dose-dependent neutralization curves; C, ID50). For neutralization against the KAN-1 strain, mice immunized with NIBRG-14 or rAd (KAN-1) followed by HA (Anhui) had the highest levels of neutralization antibodies; mice immunized with HA (Anhui) followed by NIBRG-14 had the lowest. For neutralization against the Anhui strain (B, dose-dependent neutralization curves; D, ID50), mice immunized with Anhui rAd followed by KAN-1 HA had the highest levels of neutralization antibodies, and mice immunized with two doses of NIBRG-14 had the lowest. Asterisk (*) indicates a statistically significant difference compared to the double-dose of inactivated NIBRG-14 group (p<0.05, Student t test). Triangle (▽) indicates a statistically significant difference compared to other immunized groups (p<0.05, Student t test).
Mentions: Neutralization H5pp assays were used to determine neutralizing antibody titers elicited by the use of trimeric rHA proteins in combination with inactivated NIBRG-14 or rAd-HA versus dual-dose NIBRG-14 virus immunizations. According to our results, all of these prime-boost immunization combinations induced dose-independent neutralizing antibody responses against KAN-1 (Fig. 7A) and Anhui (Fig. 7B). The ID-50 values were higher for the inactivated NIBRG-14 virus plus trimeric rHA protein booster than for the two-dose inactivated NIBRG-14 virus immunization against the same or different H5N1 HA clade (Figs. 7C–D). An Anhui rHA protein booster induced more neutralizing antibody titers than a KAN-1 rHA protein booster following inactivated NIBRG-14 virus priming, but the difference was not statistically significant. Compared to two-dose inactivated NIBRG-14 virus immunization, priming with KAN-1 or Anhui rHA protein plus an inactivated NIBRG-14 virus booster resulted in either a slower increase or outright reduction of neutralizing antibody titers against both the homologous (clade 1) and heterologous (clade 2.3.4) strains of H5N1 viruses. Priming with KAN-1 rAd-HA followed by an Anhui rHA protein booster resulted in the highest ID50 values against KAN-1, but the difference was not statistically significant compared to two-dose inactivated NIBRG-14 virus immunization (Fig. 7C). Priming with either rAd-HA (KAN-1 or Anhui) followed by a booster with KAN-1 or Anhui rHA protein elicited stronger neutralizing antibody responses against the H5N1 Anhui clade (2.3.4) than two doses of inactivated NIBRG-14 (Fig. 7D). Priming with Anhui rAd-HA followed by a KAN-1 rHA protein booster resulted in the highest ID50 values against Anhui (Fig. 7D). The use of different HA antigen clades in adenovirus vector-primed and recombinant protein booster immunizations further enhanced neutralizing antibody responses to homologous and heterologous H5N1 virus strains.

Bottom Line: The hemagglutinin (HA) envelope protein is the primary target for subunit vaccine development.We investigated trimeric rHA protein immunogenicity in mice via immunizations, and found that the highest levels of neutralizing antibodies resulted from coupling with a PELC/CpG adjuvant.We also found that the combined use of trimeric rHA proteins with (a) an inactivated H5N1 vaccine virus, or (b) a recombinant adenovirus encoding full-length HA sequences for prime-boost immunization, further improved antibody responses against homologous and heterologous H5N1 virus strains.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biotechnology and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan.

ABSTRACT

Background: The highly pathogenic avian influenza (HPAI) H5N1 virus continues to cause disease in poultry and humans. The hemagglutinin (HA) envelope protein is the primary target for subunit vaccine development.

Methodology/principal findings: We used baculovirus-insect cell expression to obtain trimeric recombinant HA (rHA) proteins from two HPAI H5N1 viruses. We investigated trimeric rHA protein immunogenicity in mice via immunizations, and found that the highest levels of neutralizing antibodies resulted from coupling with a PELC/CpG adjuvant. We also found that the combined use of trimeric rHA proteins with (a) an inactivated H5N1 vaccine virus, or (b) a recombinant adenovirus encoding full-length HA sequences for prime-boost immunization, further improved antibody responses against homologous and heterologous H5N1 virus strains. Data from cross-clade prime-boost immunization regimens indicate that sequential immunization with different clade HA antigens increased antibody responses in terms of total IgG level and neutralizing antibody titers.

Conclusion/significance: Our findings suggest that the use of trimeric rHA in prime-boost vaccine regimens represents an alternative strategy for recombinant H5N1 vaccine development.

Show MeSH
Related in: MedlinePlus