Identification of universal diagnostic peptide candidates for neglected tropical diseases caused by cestodes through the integration of multi-genome-wide analyses and immunoinformatic predictions

Combining proteomics and bioinformatics to explore novel tegumental antigens as vaccine candidates against Echinococcus granulosus infection

“…AAR value is an inverse measure of antigenicity, mostly used to measure the antigenicity of a set of proteins. Interestingly, the mean AAR value of PSEx proteome is slightly higher than the value predicted for a set of secreted proteins from parasitic cestodes (mean AAR = 24.5) proposed as highly antigenic candidates useful for serodiagnosis . Then, when analyzing proteins' “uniqueness score”—a measure of protein divergence obtained by BLASTp against nonhelminth organisms—we observed that over 40% of PSEx proteins can be assessed as “highly divergent” (US values in the 0.5‐0.8 range) and 34% as “unique” proteins (US < 0.5).…”

“…Interestingly, the mean AAR value of PSEx proteome is slightly higher than the value predicted for a set of secreted proteins from parasitic cestodes (mean AAR = 24.5) proposed as highly antigenic candidates useful for serodiagnosis. 26 Then, when analyzing proteins' "uniqueness score"-a measure of protein divergence obtained by BLASTp against nonhelminth organisms-we observed that over 40% of PSEx proteins can be assessed as "highly divergent" (US values in the 0.5-0.8 range) and 34% as "unique" proteins (US < 0.5). On the basis of these results, and bearing in mind that PSEx is able to induce protection after immunization, 18 we propose nine new proteins to be further tested as vaccine candidates against E. granulosus infection.…”

“…Clean linear B cells epitopes that successfully passed the above‐mention pipeline were mapped within the 3D structure of their corresponding protein to analyze the antibody accessibility according to . Briefly, we first performed a 3D structure modeling by low‐homology protein threading using RaptorX software to every protein that exhibited at least one peptide that successfully passed the previous pipeline.…”

“…Then, to analyze epitope surface accessibility, selected petides etides were mapped in their 3D-modeled parental protein as described elsewhere. 26 Only models with uGDT ≥ 50 were selected, resulting in 14 good models (Figure 4). Regarding "SPRY domain containing protein" (#45 in our set), its 3D model did not reach the uGDT threshold and it was discarded from accessibility analysis ( Figure 4P).…”

Design and expression of polytopic construct of cathepsin-L1, SAP-2 and FhTP16.5 proteins of Fasciola hepatica

“…Recently, the findings have shown that synthetic peptides containing B- and T-cell epitopes of F. hepatica cathepsin cysteine proteases and amoebapore proteins (SAPs) can be good candidates to be used in serodiagnostic methods and to develop vaccines for fascioliasis (Torres & Espino, 2006; Jaros et al ., 2010; Martínez-Sernández et al ., 2011; Rojas-Caraballo et al ., 2014, 2017). The novel diagnostic peptide candidates proposed as antigens have provided acceptable results for the neglected tropical diseases caused by cestodes (Zimic et al ., 2011; Miles et al ., 2017, 2019). Further, a research on immunoinformatic approach has shown the development of a universal peptide vaccine against Schistosoma japonicum using epitope prediction (Abdalrahman et al ., 2019).…”