Dynamics of the Magnitude, Breadth and Depth of the Antibody Response at Epitope Level Following Dengue Infection

Abstract

Dengue is a major public health problem in tropical and sub-tropical regions worldwide. Since the Zika epidemic and the increased co-circulation of other arboviruses, the serology-based diagnosis of dengue has become more problematic due to the high antigenic resemblance, especially among the flavivirus family. Therefore, a more comprehensive understanding of the diversity, specificity and temporal evolution of the antibody response following dengue infection is needed. In order to close this knowledge gap, we used a high-density peptide microarray of 9,072 linear peptides covering the entire proteome diversity of dengue, Zika, yellow fever and chikungunya viruses. The IgM and IgG antibody responses were measured against the designed microarray in symptomatic dengue infected individuals from an arbovirus endemic area in Peru and in overseas travelers returning to Belgium, as representatives of multiple-exposed and primary infections, respectively. Serum samples were collected longitudinally across four time points over the period of six months in Peru and over two time points in travelers. We show that epitopes eliciting the strongest flavivirus cross-reactive antibodies, in both primary and secondary infections were concentrated in the capsid, E, NS1, NS3 and NS5 proteins. The IgG antibody responses against NS1 and NS3 followed a rise-and-fall pattern, with peak titers between two to four weeks after onset of illness. The response to the E and NS5 proteins increased rapidly in the acute phase and was maintained at stable levels until at least 6 months after illness. A more scattered IgM antibody reactivity across the viral proteome was observed in the acute phase of the disease and that persisted through the 6-month window. The magnitude, breadth (i.e. number of unique epitopes targeted) and depth (i.e. number of epitope variants recognized) of the IgG response was higher in secondary infections compared to primary infections. For IgM antibodies, the magnitude of the response was higher in primary infected individuals whereas the breadth and depth of the response was lower in this group compared with the endemic subjects. Finally, through this arboviral proteome-wide epitope mapping, we were able to identify IgM and IgG dengue-specific epitopes which can be useful serological markers for dengue diagnosis and serostatus determination.

Peptide Biomarkers for the Diagnosis of Dengue Infection

“…Of note, we have used the peptide sequences as they came off the microarray and thus the amino acid sequences have not been optimized to further enhance recognition and binding affinity. Given the individual variability of the Ab-response towards viral Ags (22), also observed in this study against the evaluated peptides, it is evident that a single unique 15-mer peptide is unlikely to offer sufficiently high sensitivity and specificity. Part of the sequence of FPG-1 peptide has been previously reported to be an immunodominant targeted by the immune system following DENV vaccination and natural infection (37), while there are no reports in scientific literature describing the PM-22 peptide sequence located in NS2A as a potential diagnostic antigen.…”

“…In this regard, extensive analysis has been performed on the characterization of immunodominant epitopes present in the flavivirus structural proteins Capsid, prM and Envelope and the non-structural protein NS1, which are main targets of the humoral immune response (19). Important epitopes present in the other non-structural proteins have also been described to be targeted by Abs (22,34) and they represent potential Ags to be used in immunoassays. The peptides evaluated in this work span the entire DENV proteome and they were based on their ability to be recognized by Abs present in the serum from DENV infected individuals (22).…”

“…Important epitopes present in the other non-structural proteins have also been described to be targeted by Abs (22,34) and they represent potential Ags to be used in immunoassays. The peptides evaluated in this work span the entire DENV proteome and they were based on their ability to be recognized by Abs present in the serum from DENV infected individuals (22). Among the evaluated peptides, PM-22 from Envelope, PM-30 from NS3, FPG-1 from NS1, PG-15B from NS1, PG-19 from NS2B, PG-24 from NS3 and PG-40 from NS5 were able to classify DENV samples in the positive category and sera from individuals with other flavivirus history in the negative category.…”

“…Nine peptides recognized by IgM Abs (PM peptides) located in the E, NS1, NS2a, NS2b, NS3, and NS4b proteins, and 11 peptides recognized by IgG Abs (PG peptides) located in the prM, E, NS1, NS2b, NS3, NS4b, and NS5 proteins and that were previously identified to be highly immunogenic (22) were selected for further analysis. Figure 1 shows the location of the peptides in the DENV proteome.…”

“…In previous work, we screened a 15-mer peptide microarray library covering the entire proteomes of the four DENV serotypes, ZIKV and YFV and identified 20 immunodominant peptides that were recognized by the sera of DENV infected individuals (22). Using a Using a bead-based multiplex peptide immunoassay (MPIA), we report here the diagnostic potential of the selected synthetic peptides on a larger panel of carefully selected sera from individuals previously infected with DENV, ZIKV, YFV, WNV, CHIKV, and HIV or receiving vaccination against YFV, TBEV or JEV.…”