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Characterization of monoclonal antibodies against foot-and-mouth disease virus serotype O and application in identification of antigenic variation in relation to vaccine strain selection.

Yang M, Xu W, Goolia M, Zhang Z - Virol. J. (2014)

Bottom Line: Isolates ECU/4/10 and HKN/2/11 demonstrated the highest antigenic variation compared to the others.The amino acid sequences of the outer capsid proteins for these nine isolates were analyzed and compared with the vaccine strain O1/Manisa.However, for vaccine matching VNT remains the preferred method but a combination of VNT, antigenic profiling with a panel of mAbs and genetic sequencing would probably be more ideal for full characterization of any new outbreak isolates as well as for selection of vaccine strains from FMDV antigen banks.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Centre for Foreign Animal Disease, 1015 Arlington Street, Winnipeg R3E 3 M4, Manitoba, Canada. Ming.Yang@inspection.gc.ca.

ABSTRACT

Background: Foot-and-mouth disease (FMD) has severe implications for animal farming which leads to considerable financial losses because of its rapid spread, high morbidity and loss of productivity. For these reasons, the use of vaccine is often favoured to prevent and control FMD. Selection of the proper vaccine is extremely difficult because of the antigenic variation within FMDV serotypes. The aim of the current study was to produce a panel of mAbs and use it for the characterization of new isolates of FMDV serotype O.

Results: A panel of FMDV/O specific mAb was produced. The generated mAbs were then characterized using the peptide array and mAb resistant mutant selection. Seven out of the nine mAbs reacted with five known antigenic sites, thus the other two mAbs against non-neutralizing sites were identified. The mAbs were then evaluated by antigenic ELISA for the detection of forty-six FMDV serotype O isolates representing seven of ten known topotypes. Isolates ECU/4/10 and HKN/2/11 demonstrated the highest antigenic variation compared to the others. Furthermore, the panel of mAbs was used in vaccine matching by antigenic profiling ELISA with O1/Manisa as the reference strain. However, there was no correlation between vaccine matching by antigenic ELISA and the gold standard method, virus neutralisation test (VNT), for the forty-six FMDV/O isolates. Nine isolates had particularly poor correlation with the reference vaccine strain as revealed by the low r1 values in VNT. The amino acid sequences of the outer capsid proteins for these nine isolates were analyzed and compared with the vaccine strain O1/Manisa. The isolate ECU/4/10 displayed three unique amino acid substitutions around the antigenic sites 1, 3 and 4.

Conclusions: The panel of mAbs is useful to monitor the emergence of antigenically different strains and determination of relevant antigenic site differences. However, for vaccine matching VNT remains the preferred method but a combination of VNT, antigenic profiling with a panel of mAbs and genetic sequencing would probably be more ideal for full characterization of any new outbreak isolates as well as for selection of vaccine strains from FMDV antigen banks.

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Alignment of partial capsid amino acid sequences of unmatched FMDV/O field isolates and reference strain O1/Manisa. The capsid proteins of VP1, VP2, and VP3 of the 9 FMDV isolates (shown in Table 3) were aligned by Clustal-W. Only the regions containing 5 previously determined antigenic sites and unique amino acid substitutions of unmatched isolates and reference strain are shown for clarity. The identical amino acid residues are indicated by dots. Amino acid deletions are indicated as hyphens. The single letter amino acid code is used. Previously identified antigenic sites for FMDV/O are indicated with solid horizontal lines or closed circles above the sequences. Amino acid residues with unique substitutions in the 9 sequences are indicated by open boxes, and the VP1 GH loop residues 130-160 is indicated by a dashed line shown above the sequences.
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Figure 3: Alignment of partial capsid amino acid sequences of unmatched FMDV/O field isolates and reference strain O1/Manisa. The capsid proteins of VP1, VP2, and VP3 of the 9 FMDV isolates (shown in Table 3) were aligned by Clustal-W. Only the regions containing 5 previously determined antigenic sites and unique amino acid substitutions of unmatched isolates and reference strain are shown for clarity. The identical amino acid residues are indicated by dots. Amino acid deletions are indicated as hyphens. The single letter amino acid code is used. Previously identified antigenic sites for FMDV/O are indicated with solid horizontal lines or closed circles above the sequences. Amino acid residues with unique substitutions in the 9 sequences are indicated by open boxes, and the VP1 GH loop residues 130-160 is indicated by a dashed line shown above the sequences.

Mentions: To better understand antigenic relations between the vaccine strain and field isolates at amino acid level, the amino acid sequences of outer capsid proteins were analyzed. Comparison of the five antigenic sites recognized by the mAb panel revealed that antigenic sites 2, 3 and 4 are identical for O1/BFS and O1/Manisa. There are two and six amino acids variations for antigenic site 1a and 1b recognized by the mAbs F12VP1O2-1 and F21-64, respectively for O1/BFS and O1/Manisa. The nine isolates with r1 < 0.3 in 2D-VNT were investigated and compared with the vaccine strain O1/Manisa. Figure 3 summarized amino acid alterations observed on the surface of outer capsid proteins in/near five known antigenic sites. In comparison with a vaccine strain O1/Manisa, analysis of 5 previously identified antigenic sites indicated that ECU/4/10 has the highest antigenic variation in or near antigenic sites. This isolate displays three unique amino acid substitutions around the neutralizing sites 1, 3 and 4. There are amino acid deletions at 139 VP1 GH loop and other amino acid substitutions located on VP1 and VP3. The high sequence variation of the ECU/4/10 explained the low r1 value in 2D-VNT (r1 = 0.05) and a very weak correlation coefficient (r = 0.184) in antigenic profiling ELISA (Table 2). The isolate ETH/39/09 has unique amino acid alterations located around the antigenic site 2 and 3. However, the binding of the mAb panel with ETH/39/09 failed to show any significant reduction at these locations. But a low binding was observed with the mAb (F12VP1O-2) located on VP1 C-terminal (Table 3).


Characterization of monoclonal antibodies against foot-and-mouth disease virus serotype O and application in identification of antigenic variation in relation to vaccine strain selection.

Yang M, Xu W, Goolia M, Zhang Z - Virol. J. (2014)

Alignment of partial capsid amino acid sequences of unmatched FMDV/O field isolates and reference strain O1/Manisa. The capsid proteins of VP1, VP2, and VP3 of the 9 FMDV isolates (shown in Table 3) were aligned by Clustal-W. Only the regions containing 5 previously determined antigenic sites and unique amino acid substitutions of unmatched isolates and reference strain are shown for clarity. The identical amino acid residues are indicated by dots. Amino acid deletions are indicated as hyphens. The single letter amino acid code is used. Previously identified antigenic sites for FMDV/O are indicated with solid horizontal lines or closed circles above the sequences. Amino acid residues with unique substitutions in the 9 sequences are indicated by open boxes, and the VP1 GH loop residues 130-160 is indicated by a dashed line shown above the sequences.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4125342&req=5

Figure 3: Alignment of partial capsid amino acid sequences of unmatched FMDV/O field isolates and reference strain O1/Manisa. The capsid proteins of VP1, VP2, and VP3 of the 9 FMDV isolates (shown in Table 3) were aligned by Clustal-W. Only the regions containing 5 previously determined antigenic sites and unique amino acid substitutions of unmatched isolates and reference strain are shown for clarity. The identical amino acid residues are indicated by dots. Amino acid deletions are indicated as hyphens. The single letter amino acid code is used. Previously identified antigenic sites for FMDV/O are indicated with solid horizontal lines or closed circles above the sequences. Amino acid residues with unique substitutions in the 9 sequences are indicated by open boxes, and the VP1 GH loop residues 130-160 is indicated by a dashed line shown above the sequences.
Mentions: To better understand antigenic relations between the vaccine strain and field isolates at amino acid level, the amino acid sequences of outer capsid proteins were analyzed. Comparison of the five antigenic sites recognized by the mAb panel revealed that antigenic sites 2, 3 and 4 are identical for O1/BFS and O1/Manisa. There are two and six amino acids variations for antigenic site 1a and 1b recognized by the mAbs F12VP1O2-1 and F21-64, respectively for O1/BFS and O1/Manisa. The nine isolates with r1 < 0.3 in 2D-VNT were investigated and compared with the vaccine strain O1/Manisa. Figure 3 summarized amino acid alterations observed on the surface of outer capsid proteins in/near five known antigenic sites. In comparison with a vaccine strain O1/Manisa, analysis of 5 previously identified antigenic sites indicated that ECU/4/10 has the highest antigenic variation in or near antigenic sites. This isolate displays three unique amino acid substitutions around the neutralizing sites 1, 3 and 4. There are amino acid deletions at 139 VP1 GH loop and other amino acid substitutions located on VP1 and VP3. The high sequence variation of the ECU/4/10 explained the low r1 value in 2D-VNT (r1 = 0.05) and a very weak correlation coefficient (r = 0.184) in antigenic profiling ELISA (Table 2). The isolate ETH/39/09 has unique amino acid alterations located around the antigenic site 2 and 3. However, the binding of the mAb panel with ETH/39/09 failed to show any significant reduction at these locations. But a low binding was observed with the mAb (F12VP1O-2) located on VP1 C-terminal (Table 3).

Bottom Line: Isolates ECU/4/10 and HKN/2/11 demonstrated the highest antigenic variation compared to the others.The amino acid sequences of the outer capsid proteins for these nine isolates were analyzed and compared with the vaccine strain O1/Manisa.However, for vaccine matching VNT remains the preferred method but a combination of VNT, antigenic profiling with a panel of mAbs and genetic sequencing would probably be more ideal for full characterization of any new outbreak isolates as well as for selection of vaccine strains from FMDV antigen banks.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Centre for Foreign Animal Disease, 1015 Arlington Street, Winnipeg R3E 3 M4, Manitoba, Canada. Ming.Yang@inspection.gc.ca.

ABSTRACT

Background: Foot-and-mouth disease (FMD) has severe implications for animal farming which leads to considerable financial losses because of its rapid spread, high morbidity and loss of productivity. For these reasons, the use of vaccine is often favoured to prevent and control FMD. Selection of the proper vaccine is extremely difficult because of the antigenic variation within FMDV serotypes. The aim of the current study was to produce a panel of mAbs and use it for the characterization of new isolates of FMDV serotype O.

Results: A panel of FMDV/O specific mAb was produced. The generated mAbs were then characterized using the peptide array and mAb resistant mutant selection. Seven out of the nine mAbs reacted with five known antigenic sites, thus the other two mAbs against non-neutralizing sites were identified. The mAbs were then evaluated by antigenic ELISA for the detection of forty-six FMDV serotype O isolates representing seven of ten known topotypes. Isolates ECU/4/10 and HKN/2/11 demonstrated the highest antigenic variation compared to the others. Furthermore, the panel of mAbs was used in vaccine matching by antigenic profiling ELISA with O1/Manisa as the reference strain. However, there was no correlation between vaccine matching by antigenic ELISA and the gold standard method, virus neutralisation test (VNT), for the forty-six FMDV/O isolates. Nine isolates had particularly poor correlation with the reference vaccine strain as revealed by the low r1 values in VNT. The amino acid sequences of the outer capsid proteins for these nine isolates were analyzed and compared with the vaccine strain O1/Manisa. The isolate ECU/4/10 displayed three unique amino acid substitutions around the antigenic sites 1, 3 and 4.

Conclusions: The panel of mAbs is useful to monitor the emergence of antigenically different strains and determination of relevant antigenic site differences. However, for vaccine matching VNT remains the preferred method but a combination of VNT, antigenic profiling with a panel of mAbs and genetic sequencing would probably be more ideal for full characterization of any new outbreak isolates as well as for selection of vaccine strains from FMDV antigen banks.

Show MeSH
Related in: MedlinePlus