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Cross-neutralizing antibodies to pandemic 2009 H1N1 and recent seasonal H1N1 influenza A strains influenced by a mutation in hemagglutinin subunit 2.

Wang W, Anderson CM, De Feo CJ, Zhuang M, Yang H, Vassell R, Xie H, Ye Z, Scott D, Weiss CD - PLoS Pathog. (2011)

Bottom Line: However, 68% of age-matched subjects who received the same seasonal influenza vaccines, but did not receive the 1976 swine influenza vaccine, also had sera that neutralized 2009 H1N1.Sera from both 1976 and contemporary cohorts frequently had cross-neutralizing antibodies to 2009 H1N1 and A/New Caledonia/20/1999 that mapped to hemagglutinin subunit 2 (HA2).These findings highlight a cross-neutralization determinant influenced by a point mutation in HA2 and suggest that HA2 may be evolving under direct or indirect immune pressure.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunoregulation, Division of Viral Products, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, United States of America.

ABSTRACT
Pandemic 2009 H1N1 influenza A virus (2009 H1N1) differs from H1N1 strains that circulated in the past 50 years, but resembles the A/New Jersey/1976 H1N1 strain used in the 1976 swine influenza vaccine. We investigated whether sera from persons immunized with the 1976 swine influenza or recent seasonal influenza vaccines, or both, neutralize 2009 H1N1. Using retroviral pseudovirions bearing hemagglutinins on their surface (HA-pseudotypes), we found that 77% of the sera collected in 1976 after immunization with the A/New Jersey/1976 H1N1 swine influenza vaccine neutralized 2009 H1N1. Forty five percent also neutralized A/New Caledonia/20/1999 H1N1, a strain used in seasonal influenza vaccines during the 2000/01-2006/07 seasons. Among adults aged 48-64 who received the swine influenza vaccine in 1976 and recent seasonal influenza vaccines during the 2004/05-2008/09 seasons, 83% had sera that neutralized 2009 H1N1. However, 68% of age-matched subjects who received the same seasonal influenza vaccines, but did not receive the 1976 swine influenza vaccine, also had sera that neutralized 2009 H1N1. Sera from both 1976 and contemporary cohorts frequently had cross-neutralizing antibodies to 2009 H1N1 and A/New Caledonia/20/1999 that mapped to hemagglutinin subunit 2 (HA2). A conservative mutation in HA2 corresponding to a residue in the A/Solomon Islands/3/2006 and A/Brisbane/59/2007 H1N1 strains that circulated in the 2006/07 and 2007/08 influenza seasons, respectively, abrogated this neutralization. These findings highlight a cross-neutralization determinant influenced by a point mutation in HA2 and suggest that HA2 may be evolving under direct or indirect immune pressure.

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The amino acid at position 89 in HA2 influences neutralization to HA2.(A) Sequence comparison of HA2 from Bris/59/07 and NCD/20/99. The differing residues in the HA2 are indicated (grey). (B) The 89L mutation, but not the 146N mutation in HA2 of Bris/59/07, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to NCD/20/99 HA-pseudotypes, using sera from the NJ/76 vaccine trials that have neutralization titers to NCD/20/99, but not to wild-type Bris/59/07. (C) The 89L mutation, but not the 146N mutation in Bris/59/07 HA2, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to chimeric HA-pseudotypes with Mex/4108/09 HA2, using the contemporary sera cohort from samples that have neutralization titers to Mex/4108/09 HA2 (determined in Figure 5A), but not to wild type Bris/59/07. The dotted lines in both panels B and C represent the neutralization titer of 160, which has been proposed as a correlate of seroprotection in microneutralization assays involving replicating influenza virus [4]. Protective titers for neutralization of HA-pseudotypes have not been determined. Data are shown as means +/− SD and reflect two or more independent experiments with each sample run in duplicate. Bris: Bris/59/07; Mex: Mex/4108/09; NCD: NCD/20/99.
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ppat-1002081-g006: The amino acid at position 89 in HA2 influences neutralization to HA2.(A) Sequence comparison of HA2 from Bris/59/07 and NCD/20/99. The differing residues in the HA2 are indicated (grey). (B) The 89L mutation, but not the 146N mutation in HA2 of Bris/59/07, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to NCD/20/99 HA-pseudotypes, using sera from the NJ/76 vaccine trials that have neutralization titers to NCD/20/99, but not to wild-type Bris/59/07. (C) The 89L mutation, but not the 146N mutation in Bris/59/07 HA2, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to chimeric HA-pseudotypes with Mex/4108/09 HA2, using the contemporary sera cohort from samples that have neutralization titers to Mex/4108/09 HA2 (determined in Figure 5A), but not to wild type Bris/59/07. The dotted lines in both panels B and C represent the neutralization titer of 160, which has been proposed as a correlate of seroprotection in microneutralization assays involving replicating influenza virus [4]. Protective titers for neutralization of HA-pseudotypes have not been determined. Data are shown as means +/− SD and reflect two or more independent experiments with each sample run in duplicate. Bris: Bris/59/07; Mex: Mex/4108/09; NCD: NCD/20/99.

Mentions: In 1993 [14] and again in a number of recent studies [15]–[20], neutralizing monoclonal antibodies that are broadly active against many influenza subtypes have been identified and mapped to epitopes in the stalk regions of the HA2 subunit [14], [16]–[20]. Although some of the cross-neutralization that we observed in our sera appears to map to the HA2 subunit, our data indicated that this cross-neutralization may be strain specific. As shown in Figure 4, Figure 5A and Figure 6, we found that sera with cross-neutralization to NCD/20/99 and Mex/4108/09 HA2 did not neutralize Bris/59/07. Significantly, there are only two amino acid differences in HA2, at the positions 89 (415 in full HA) and 146 (472 in full HA) between NCD/20/99 and Bris/59/07 HA2 (Figure 6A), suggesting that these two amino acids could influence HA2 antigenicity. When a leucine at residue 89 in HA2 (89L) or an asparagine at position 146 in HA2 (146N) corresponding to NCD/20/99 HA2 were introduced into Bris/59/07 HA2, the sera without cross-neutralization to Bris/59/07 HA showed neutralization to Bris/59/07 HA2-89L, but not to Bris/59/07 HA2-146N, with titers similar to NCD/20/99 HA and Bris.HA1-Mex.HA2 (Figure 6B and 6C). When both 89L and 146N were presented in Bris/59/07 HA2, serum titers were the same as those to Bris.HA1-NCD.HA2 in Figure 4 (data not shown). These results demonstrated that the neutralization epitopes in HA2 were influenced by residue 89 in HA2 (415 in full HA).


Cross-neutralizing antibodies to pandemic 2009 H1N1 and recent seasonal H1N1 influenza A strains influenced by a mutation in hemagglutinin subunit 2.

Wang W, Anderson CM, De Feo CJ, Zhuang M, Yang H, Vassell R, Xie H, Ye Z, Scott D, Weiss CD - PLoS Pathog. (2011)

The amino acid at position 89 in HA2 influences neutralization to HA2.(A) Sequence comparison of HA2 from Bris/59/07 and NCD/20/99. The differing residues in the HA2 are indicated (grey). (B) The 89L mutation, but not the 146N mutation in HA2 of Bris/59/07, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to NCD/20/99 HA-pseudotypes, using sera from the NJ/76 vaccine trials that have neutralization titers to NCD/20/99, but not to wild-type Bris/59/07. (C) The 89L mutation, but not the 146N mutation in Bris/59/07 HA2, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to chimeric HA-pseudotypes with Mex/4108/09 HA2, using the contemporary sera cohort from samples that have neutralization titers to Mex/4108/09 HA2 (determined in Figure 5A), but not to wild type Bris/59/07. The dotted lines in both panels B and C represent the neutralization titer of 160, which has been proposed as a correlate of seroprotection in microneutralization assays involving replicating influenza virus [4]. Protective titers for neutralization of HA-pseudotypes have not been determined. Data are shown as means +/− SD and reflect two or more independent experiments with each sample run in duplicate. Bris: Bris/59/07; Mex: Mex/4108/09; NCD: NCD/20/99.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3111540&req=5

ppat-1002081-g006: The amino acid at position 89 in HA2 influences neutralization to HA2.(A) Sequence comparison of HA2 from Bris/59/07 and NCD/20/99. The differing residues in the HA2 are indicated (grey). (B) The 89L mutation, but not the 146N mutation in HA2 of Bris/59/07, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to NCD/20/99 HA-pseudotypes, using sera from the NJ/76 vaccine trials that have neutralization titers to NCD/20/99, but not to wild-type Bris/59/07. (C) The 89L mutation, but not the 146N mutation in Bris/59/07 HA2, conferred similar levels of neutralization to Bris/59/07 HA-pseudotypes as compared to chimeric HA-pseudotypes with Mex/4108/09 HA2, using the contemporary sera cohort from samples that have neutralization titers to Mex/4108/09 HA2 (determined in Figure 5A), but not to wild type Bris/59/07. The dotted lines in both panels B and C represent the neutralization titer of 160, which has been proposed as a correlate of seroprotection in microneutralization assays involving replicating influenza virus [4]. Protective titers for neutralization of HA-pseudotypes have not been determined. Data are shown as means +/− SD and reflect two or more independent experiments with each sample run in duplicate. Bris: Bris/59/07; Mex: Mex/4108/09; NCD: NCD/20/99.
Mentions: In 1993 [14] and again in a number of recent studies [15]–[20], neutralizing monoclonal antibodies that are broadly active against many influenza subtypes have been identified and mapped to epitopes in the stalk regions of the HA2 subunit [14], [16]–[20]. Although some of the cross-neutralization that we observed in our sera appears to map to the HA2 subunit, our data indicated that this cross-neutralization may be strain specific. As shown in Figure 4, Figure 5A and Figure 6, we found that sera with cross-neutralization to NCD/20/99 and Mex/4108/09 HA2 did not neutralize Bris/59/07. Significantly, there are only two amino acid differences in HA2, at the positions 89 (415 in full HA) and 146 (472 in full HA) between NCD/20/99 and Bris/59/07 HA2 (Figure 6A), suggesting that these two amino acids could influence HA2 antigenicity. When a leucine at residue 89 in HA2 (89L) or an asparagine at position 146 in HA2 (146N) corresponding to NCD/20/99 HA2 were introduced into Bris/59/07 HA2, the sera without cross-neutralization to Bris/59/07 HA showed neutralization to Bris/59/07 HA2-89L, but not to Bris/59/07 HA2-146N, with titers similar to NCD/20/99 HA and Bris.HA1-Mex.HA2 (Figure 6B and 6C). When both 89L and 146N were presented in Bris/59/07 HA2, serum titers were the same as those to Bris.HA1-NCD.HA2 in Figure 4 (data not shown). These results demonstrated that the neutralization epitopes in HA2 were influenced by residue 89 in HA2 (415 in full HA).

Bottom Line: However, 68% of age-matched subjects who received the same seasonal influenza vaccines, but did not receive the 1976 swine influenza vaccine, also had sera that neutralized 2009 H1N1.Sera from both 1976 and contemporary cohorts frequently had cross-neutralizing antibodies to 2009 H1N1 and A/New Caledonia/20/1999 that mapped to hemagglutinin subunit 2 (HA2).These findings highlight a cross-neutralization determinant influenced by a point mutation in HA2 and suggest that HA2 may be evolving under direct or indirect immune pressure.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunoregulation, Division of Viral Products, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, United States of America.

ABSTRACT
Pandemic 2009 H1N1 influenza A virus (2009 H1N1) differs from H1N1 strains that circulated in the past 50 years, but resembles the A/New Jersey/1976 H1N1 strain used in the 1976 swine influenza vaccine. We investigated whether sera from persons immunized with the 1976 swine influenza or recent seasonal influenza vaccines, or both, neutralize 2009 H1N1. Using retroviral pseudovirions bearing hemagglutinins on their surface (HA-pseudotypes), we found that 77% of the sera collected in 1976 after immunization with the A/New Jersey/1976 H1N1 swine influenza vaccine neutralized 2009 H1N1. Forty five percent also neutralized A/New Caledonia/20/1999 H1N1, a strain used in seasonal influenza vaccines during the 2000/01-2006/07 seasons. Among adults aged 48-64 who received the swine influenza vaccine in 1976 and recent seasonal influenza vaccines during the 2004/05-2008/09 seasons, 83% had sera that neutralized 2009 H1N1. However, 68% of age-matched subjects who received the same seasonal influenza vaccines, but did not receive the 1976 swine influenza vaccine, also had sera that neutralized 2009 H1N1. Sera from both 1976 and contemporary cohorts frequently had cross-neutralizing antibodies to 2009 H1N1 and A/New Caledonia/20/1999 that mapped to hemagglutinin subunit 2 (HA2). A conservative mutation in HA2 corresponding to a residue in the A/Solomon Islands/3/2006 and A/Brisbane/59/2007 H1N1 strains that circulated in the 2006/07 and 2007/08 influenza seasons, respectively, abrogated this neutralization. These findings highlight a cross-neutralization determinant influenced by a point mutation in HA2 and suggest that HA2 may be evolving under direct or indirect immune pressure.

Show MeSH
Related in: MedlinePlus