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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

Antibody responses in mice with combined immunizations.Mice were immunized with trimeric KAN-1 or Anhui HA proteins in combination with inactivated H5N1 vaccine virus NIBRG-14 (clade 1), or a recombinant adenovirus encoding the full-length HA of KAN-1 [rAd(KAN-1)] or Anhui [rAd(Anhui)]. Total IgG titers from antisera against KAN-1 (A) and Anhui (B) were measured using ELISA; IgG1 and IgG2a against KAN-1 (C) and Anhui (D) were also determined. Values are expressed as geometric mean with a standard error of the mean of five mice per group. 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-g006: Antibody responses in mice with combined immunizations.Mice were immunized with trimeric KAN-1 or Anhui HA proteins in combination with inactivated H5N1 vaccine virus NIBRG-14 (clade 1), or a recombinant adenovirus encoding the full-length HA of KAN-1 [rAd(KAN-1)] or Anhui [rAd(Anhui)]. Total IgG titers from antisera against KAN-1 (A) and Anhui (B) were measured using ELISA; IgG1 and IgG2a against KAN-1 (C) and Anhui (D) were also determined. Values are expressed as geometric mean with a standard error of the mean of five mice per group. 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: We also evaluated the combined use of trimeric rHA proteins coupled with the PELC/CpG adjuvant, using either inactivated H5N1 NIBRG-14 virus, or a recombinant adenovirus encoding the full-length HA gene of KAN-1 (H5N1 clade 1) or Anhui (H5N1 clade 2.3.4). Mice immunized with the inactivated NIBRG-14 virus followed by a booster with a trimeric rHA protein elicited slightly higher total IgG titers compared to mice receiving double-NIBRG-14 virus immunizations (Fig. 6A–B). Priming with rAd-HA (Anhui) followed by a booster with a trimeric rHA protein (KAN-1) resulted in the highest anti-Anhui rHA total IgG titer (Fig. 6B). Compared to mice receiving a double-dose of inactivated NIBRG-14, increases of IgG1 subtypes and (to a lesser degree) IgG2a subtypes were observed in mice receiving an initial immunization of inactivated NIBRG-14, rAd-HA (KAN-1), or rAd-HA (Anhui) followed by a booster with KAN-1 or Anhui trimeric rHA proteins (Fig. 6C–D). These combinations produced more balanced Th1 and Th2 responses compared to inactivated NIBRG-14 virus immunization with a trimeric HA protein booster, or two doses of inactivated NIBRG-14.


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)

Antibody responses in mice with combined immunizations.Mice were immunized with trimeric KAN-1 or Anhui HA proteins in combination with inactivated H5N1 vaccine virus NIBRG-14 (clade 1), or a recombinant adenovirus encoding the full-length HA of KAN-1 [rAd(KAN-1)] or Anhui [rAd(Anhui)]. Total IgG titers from antisera against KAN-1 (A) and Anhui (B) were measured using ELISA; IgG1 and IgG2a against KAN-1 (C) and Anhui (D) were also determined. Values are expressed as geometric mean with a standard error of the mean of five mice per group. 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).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3104987&req=5

pone-0020052-g006: Antibody responses in mice with combined immunizations.Mice were immunized with trimeric KAN-1 or Anhui HA proteins in combination with inactivated H5N1 vaccine virus NIBRG-14 (clade 1), or a recombinant adenovirus encoding the full-length HA of KAN-1 [rAd(KAN-1)] or Anhui [rAd(Anhui)]. Total IgG titers from antisera against KAN-1 (A) and Anhui (B) were measured using ELISA; IgG1 and IgG2a against KAN-1 (C) and Anhui (D) were also determined. Values are expressed as geometric mean with a standard error of the mean of five mice per group. 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: We also evaluated the combined use of trimeric rHA proteins coupled with the PELC/CpG adjuvant, using either inactivated H5N1 NIBRG-14 virus, or a recombinant adenovirus encoding the full-length HA gene of KAN-1 (H5N1 clade 1) or Anhui (H5N1 clade 2.3.4). Mice immunized with the inactivated NIBRG-14 virus followed by a booster with a trimeric rHA protein elicited slightly higher total IgG titers compared to mice receiving double-NIBRG-14 virus immunizations (Fig. 6A–B). Priming with rAd-HA (Anhui) followed by a booster with a trimeric rHA protein (KAN-1) resulted in the highest anti-Anhui rHA total IgG titer (Fig. 6B). Compared to mice receiving a double-dose of inactivated NIBRG-14, increases of IgG1 subtypes and (to a lesser degree) IgG2a subtypes were observed in mice receiving an initial immunization of inactivated NIBRG-14, rAd-HA (KAN-1), or rAd-HA (Anhui) followed by a booster with KAN-1 or Anhui trimeric rHA proteins (Fig. 6C–D). These combinations produced more balanced Th1 and Th2 responses compared to inactivated NIBRG-14 virus immunization with a trimeric HA protein booster, or two doses of inactivated NIBRG-14.

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