Increased Mannosylation of Extracellular Vesicles in Long COVID Plasma as a Binding Target for Galanthus nivalis Agglutinin (GNA) Affinity Resin

There is no proven therapy for Long COVID, a post-acute condition characterized by persistent symptoms following SARS-CoV-2 infection. Extracellular vesicles (EVs) are emerging as mediators of disease pathogenesis through their molecular cargo. We investigated whether EV glycosylation is altered in Long COVID plasma and whether these vesicles can be selectively targeted using a glycan-binding affinity resin. Large (100–500 nm) and small (40–200 nm) EVs were isolated from post-acute COVID-19 plasma and analyzed by nanoparticle flow cytometry to assess surface glycosylation. Small EV capture assays were performed using Galanthus nivalis agglutinin (GNA) affinity resin. Plasma miRNA profiles before and after GNA treatment were evaluated using NanoString nCounter analysis, and potential downstream pathway effects were computationally inferred using validated miRNA–mRNA interactions and PROGENy. Mannose-positive large EVs were significantly increased in Long COVID compared to recovered controls (p < 0.05). GNA-mediated small EV capture correlated with mannose-positive EV abundance (r = 0.341, p < 0.05), and seven miRNAs were significantly reduced following treatment. Computational pathway analysis suggested modulation of key signaling pathways, including JAK-STAT, Estrogen, VEGF, and PI3K. These findings suggest a glycan-associated EV signature in Long COVID and support further investigation of lectin-based capture as a potential strategy to target vesicle-associated molecular cargo.