IgG subclass-based serodiagnosis of Schistosoma mansoni using C-type lectin-derived peptides

• IgG subclass profiling improves discrimination of S. mansoni peptides • CTL-1–derived peptides identify S. mansoni -specific IgG1 reactivity • IgG2a responses exhibit low specificity for S. mansoni • BLASTp supports the biological relevance of 12 selected diagnostic peptides • Subclass-resolved serology reduces cross-reactivity among helminths Schistosomiasis remains a public health concern in Brazil and is classified by the World Health Organization (WHO) as a Neglected Tropical Disease (NTD). Limitations of current diagnostic methods highlight the need for more sensitive approaches that improve the detection of Schistosoma mansoni while minimizing cross-reactivity with related helminths. Helminthiases contribute substantially to the global burden of disability-adjusted life years (DALYs). In this study, a peptide-based immunodiagnostic strategy was applied using sequences derived from a C-type lectin protein to evaluate relative specificity for S. mansoni . Immunoblotting assays were performed with sera from uninfected and infected mice experimentally exposed to T. canis, A. suum , and S. mansoni . Antibody detection was performed using IgG1 and IgG2a subclasses against imprinting peptides in cellulose membrane. Reactivity was assessed by densitometric analysis using ImageJ software and by sequence homology analysis with BLASTp. The results showed strong IgG1-mediated recognition of specific peptides in S. mansoni infection, whereas IgG2a exhibited lower reactivity. Eleven IgG1-reactive peptides and one IgG2a-reactive peptide reached the established selection criteria. BLASTp analysis revealed homology between selected peptides and metabolic and structural proteins of the parasite, supporting their biological relevance. These findings indicate that an IgG subclass–based peptide strategy may improve the differential serodiagnosis of helminth infections. Further immunoenzymatic studies using soluble synthetic peptides are required to confirm diagnostic performance in endemic settings.