» Articles » PMID: 22546090

Epitope Reactions Can Be Gauged by Relative Antibody Discriminating Specificity (RADS) Values Supported by Deletion, Substitution and Cysteine Bridge Formation Analyses: Potential Uses in Pathogenesis Studies

Overview
Journal BMC Res Notes
Publisher Biomed Central
Date 2012 May 2
PMID 22546090
Citations 2
Authors
Affiliations
Soon will be listed here.
Abstract

Background: Epitope-mapping of infectious agents is essential for pathogenesis studies. Since polyclonal antibodies (PAbs) and monoclonal antibodies (MAbs) are always polyspecific and can react with multiple epitopes, it is important to distinguish between specific and non-specific reactions. Relative antibody discriminating specificity (RADS) values, obtained from their relative ELISA reactions with L-amino acid peptides prepared in the natural versus reverse orientations (x-fold absorbance natural/absorbance reverse = RADS value) may be valuable for this purpose.PAbs generated against the dengue type-2 virus (DENV-2) nonstructural-1 (NS1) glycoprotein candidate vaccine also reacted with both DENV envelope (E) glycoproteins and blood-clotting proteins. New xKGSx/xSGKx amino acid motifs were identified on DENV-2 glycoproteins, HIV-1 gp41 and factor IXa. Their potential roles in DENV and HIV-1 antibody-enhanced replication (AER) and auto-immunity were assessed.In this study, a) RADS values were determined for MAbs and PAbs, generated in congeneic (H2: class II) mice against DENV NS1 glycoprotein epitopes, to account for their cross-reaction patterns, and b) MAb 1G5.3 reactions with xKGSx/xSGKx motifs present in the DENV-4 NS1, E and HIV-1 glycoproteins and factor IXa were assessed after the introduction of amino acid substitutions, deletions, or intra-/inter-cysteine (C-C) bridges.

Results: MAbs 1H7.4, 5H4.3, 3D1.4 and 1G5.3 had high (4.23- to 16.83-fold) RADS values against single epitopes on the DENV-2 NS1 glycoprotein, and MAb 3D1.4 defined the DENV complex-conserved LX1 epitope. In contrast, MAbs 1G5.4-A1-C3 and 1C6.3 had low (0.47- to 1.67-fold) RADS values against multiple epitopes. PAb DENV complex-reactions occurred through moderately-high (2.77- and 3.11-fold) RADS values against the LX1 epitope. MAb 1G5.3 reacted with xSGKx motifs present in DENV-4 NS1 and E glycoproteins, HIV-1 gp41 and factor IXa, while natural C-C bridge formations or certain amino acid substitutions increased its binding activity.

Conclusions: These results: i) were readily obtained using a standard 96-well ELISA format, ii) showed the LX1 epitope to be the immuno-dominant DENV complex determinant in the NS1 glycoprotein, iii) supported an antigenic co-evolution of the DENV NS1 and E glycoproteins, and iv) identified methods that made it possible to determine the role of anti-DENV PAb reactions in viral pathogenesis.

Citing Articles

Refining wet lab experiments with in silico searches: A rational quest for diagnostic peptides in visceral leishmaniasis.

Bremer Hinckel B, Marlais T, Airs S, Bhattacharyya T, Imamura H, Dujardin J PLoS Negl Trop Dis. 2019; 13(5):e0007353.

PMID: 31059497 PMC: 6522066. DOI: 10.1371/journal.pntd.0007353.


Development of peptide-based lineage-specific serology for chronic Chagas disease: geographical and clinical distribution of epitope recognition.

Bhattacharyya T, Falconar A, Luquetti A, Costales J, Grijalva M, Lewis M PLoS Negl Trop Dis. 2014; 8(5):e2892.

PMID: 24852444 PMC: 4031129. DOI: 10.1371/journal.pntd.0002892.

References
1.
Fust G . Enhancing antibodies in HIV infection. Parasitology. 1997; 115 Suppl:S127-40. DOI: 10.1017/s0031182097001819. View

2.
Richards F, Konigsberg W, Rosenstein R, VARGA J . On the specificity of antibodies. Science. 1975; 187(4172):130-7. DOI: 10.1126/science.46122. View

3.
Shashidharamurthy R, Zhang F, Amano A, Kamat A, Panchanathan R, Ezekwudo D . Dynamics of the interaction of human IgG subtype immune complexes with cells expressing R and H allelic forms of a low-affinity Fc gamma receptor CD32A. J Immunol. 2009; 183(12):8216-24. PMC: 2796592. DOI: 10.4049/jimmunol.0902550. View

4.
Falconar A, Martinez F . The NS1 glycoprotein can generate dramatic antibody-enhanced dengue viral replication in normal out-bred mice resulting in lethal multi-organ disease. PLoS One. 2011; 6(6):e21024. PMC: 3120820. DOI: 10.1371/journal.pone.0021024. View

5.
Goncalvez A, Purcell R, Lai C . Epitope determinants of a chimpanzee Fab antibody that efficiently cross-neutralizes dengue type 1 and type 2 viruses map to inside and in close proximity to fusion loop of the dengue type 2 virus envelope glycoprotein. J Virol. 2004; 78(23):12919-28. PMC: 525008. DOI: 10.1128/JVI.78.23.12919-12928.2004. View