Conjugates of α-d-Galp-(1->3)-β-d-Galp for the serological diagnosis of Chagas disease.

Balouz, V.; Lopez, R.; Conte, N.; Abal, M.; Ducrey, I.; Giorgi, M. E.; de Lederkremer, R. M.; Altcheh, J.; Ciocchini, A. E.; Melli, L. J.; Marino, C.; Buscaglia, C. A.

doi:10.1101/2025.11.07.687140

bioRxiv · 10.1101/2025.11.07.687140

Conjugates of α-d-Galp-(1->3)-β-d-Galp for the serological diagnosis of Chagas disease.

Balouz, V.·Lopez, R.·Conte, N.·Abal, M.·Ducrey, I.·Giorgi, M. E.·de Lederkremer, R. M.·Altcheh, J.·Ciocchini, A. E.·Melli, L. J.·Marino, C.·Buscaglia, C. A.

View original source ↗Export metadata ↓

Abstract

BackgroundChagas disease (ChD), caused by the parasitic protozoan Trypanosoma cruzi, is a lifelong, neglected tropical disease with substantial medical and socioeconomic impact. Despite this situation, currently available diagnostic and therapeutic methods display serious limitations. A promising strategy to improve ChD serodiagnosis involves targeting parasite carbohydrate antigens, particularly the -galactosyl-rich mucins that coat the surface of bloodstream trypomastigotes (tGPI-mucins). Methods/Principle FindingsHere, we present a concise and efficient protocol for the chemical synthesis of a tGPI-mucin-derived glycotope, the disaccharide -O_SCPLOWDC_SCPLOW-Galp-(1[->]3)-{beta}-O_SCPLOWDC_SCPLOW-Galp, and its functional conjugation to different scaffolds using the squarate method. A neoglycoprotein made upon a bovine serum albumin (BSA) carrier decorated with [~]28 units of the disaccharide, termed BSA-Di, was interrogated with sera of chronic ChD patients and healthy individuals from Argentina using an in-house enzyme-linked immunosorbent assay (ELISA). BSA-Di exhibited excellent sensitivity and effectively discriminated between ChD-positive and negative sera with high accuracy (AUC = 0.905), though its specificity was partially affected by cross-reactivity of some non-ChD sera containing natural -Gal antibodies. Conjugation of -O_SCPLOWDC_SCPLOW-Galp-(1[->]3)-{beta}-O_SCPLOWDC_SCPLOW-Galp to T. cruzi antigenic peptides, instead of BSA, corroborated these findings and enabled the generation of bivalent ChD diagnostic reagents combining glycan- and peptide-based epitopes. Conclusions/SignificanceOverall, our results identify -O_SCPLOWDC_SCPLOW-Galp-(1[->]3)-{beta}-O_SCPLOWDC_SCPLOW-Galp as a robust and reliable biomarker of T. cruzi infection. The methodologies and tools described here, together with optimized derivatives, are expected to positively impact ChD serological applications. AUTHOR SUMMARYDespite the enormous burden imposed by Chagas disease, diagnostic and therapeutic methods still present serious deficiencies. Towards filling this gap, we herein developed a protocol for the chemical synthesis of -O_SCPLOWDC_SCPLOW-Galp-(1[->]3)-{beta}-O_SCPLOWDC_SCPLOW-Galp, a major glycotope present on the Trypanosoma cruzi surface coat. This disaccharide was conjugated with different molecular scaffolds and serologically evaluated using an in-house enzyme-linked immunosorbent assay (ELISA). Our results indicate that -O_SCPLOWDC_SCPLOW-Galp-(1[->]3)-{beta}-O_SCPLOWDC_SCPLOW-Galp provides an overall robust and reliable biomarker of T. cruzi infection, with excellent sensitivity and only minor concerns regarding its potential cross-reactivity with natural -Gal antibodies. These findings indicate that the tools developed here, as well as optimized versions derived from them, should have a positive impact on the diagnosis and clinical management of Chagas disease and on the identification and/or clinical validation of novel drug/vaccine candidates for the treatment of T. cruzi infections.

Source connections

Published article ↗

Explore related subjects

microbiology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Balouz, V., Lopez, R., Conte, N., Abal, M., Ducrey, I., Giorgi, M. E., de Lederkremer, R. M., Altcheh, J., Ciocchini, A. E., Melli, L. J., Marino, C., Buscaglia, C. A.. 2025-11-08. Conjugates of α-d-Galp-(1->3)-β-d-Galp for the serological diagnosis of Chagas disease.. https://doi.org/10.1101/2025.11.07.687140

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

A population-scale landscape of the subgingival microbiome reveals divergent routes to periodontal dysbiosis

Periodontitis is an archetypical mucosal inflammatory disease in which microbiome dysbiosis at the tooth-epithelial interface interacts with host genetic and behavioral risk factors to drive immune-mediated tissue destruction. Although subgingival microbiome compositional shifts are thought to parallel disease severity, microbiome variation at the population-level and its relationship to periodontal clinical phenotypes and disease-modifying factors remain poorly defined. Here, we use unsupervised manifold learning to map the compositional landscape of the subgingival microbiome in 1,355 adults spanning periodontal health to severe periodontitis. We identified eight latent microbiome states organized along a branching continuum from eubiosis to dysbiosis. An intermediate microbial configuration marked ecological destabilization and bifurcation into two distinct periodontitis-associated dysbiotic trajectories, distinguished by links to gingival inflammation and smoking. Although the microbiome trajectories broadly tracked periodontal destruction, a minority of individuals showed discordant microbiome-clinical phenotypes, with some individuals with periodontitis retaining otherwise eubiotic microbiomes enriched for low-abundance pathobionts, while some cases of health or mild disease had highly dysbiotic communities, suggesting distinct host susceptibility. Together, these findings define a population-scale ecological landscape of the subgingival microbiome, reveal divergent trajectories to periodontal dysbiosis, and highlight heterogeneity in the relationship between microbial community structure and clinical disease expression.

microbiology↗

bioRxiv2026

The iron-binding siderophore enterobactin is required for the response of multi-drug resistant Klebsiella pneumoniae to zinc limitation

To persist during infection Klebsiella pneumoniae must overcome nutrient iron and zinc limitation imposed by the host immune system through a process called nutritional immunity. Secreted small molecule siderophores are a major virulence determinant of Klebsiella pneumoniae pathogenesis and are presumed to overcome nutritional immunity by binding iron for bacterial acquisition. In this work, we set out to identify how a multi-drug resistant K. pneumoniae grows in zinc limited environments. Using unbiased transcriptomics, proteomics, and an arrayed transposon screen, we identified that synthesis and uptake of the siderophore enterobactin is required to allow for growth in low zinc conditions. Iron-specific chelators did not replicate this phenotype and addition of supplemental iron through heme in growth media could not complement severe growth defects of enterobactin mutant K. pneumoniae experiencing zinc limitation. Finally, zinc starvation induced enterobactin production independent of the canonical zinc uptake regulator (Zur) transcription factor suggesting an unidentified regulatory mechanism by which Gram-negative pathogens may respond to zinc stress. Together, these studies expand the role of enterobactin beyond iron regulation and highlight a previously unreported link between iron and zinc homeostasis in Klebsiella pneumoniae.

microbiology↗

bioRxiv2026

A microbiota-derived protease links phage susceptibility to host epithelial responses

Bacteriophages are major ecological drivers of gut microbial ecology, yet whether bacterial mechanisms that determine phage susceptibility have consequences for the mammalian host remains poorly understood. Here, we identify dipeptidyl peptidase 11 (Dpp11a), the predominant active serine protease of the prevalent gut commensal Phocaeicola vulgatus, as an unexpected bacterial defence factor. Dpp11a protects against environmental proteases and confers resistance to bacteriophage infection. Metatranscriptomic analyses further reveal increased expression of both dpp11a and P. vulgatus-associated phage transcripts in ulcerative colitis stool samples, indicating that both components of this interaction are transcriptionally active in disease-associated human microbiomes. Using the microfluidic gut-on-a-chip co-culture model HuMiX, we show that the absence of Dpp11 is accompanied by altered epithelial tight-junction remodelling during phage-bacterial infection. Together, our findings reveal that the consequences of bacterial phage defence can extend beyond phage-bacterium interactions to the mammalian epithelium.

microbiology↗