Fig. 1

Workflow of the experimental design. The Igs secreted by 5T33MM cells were purified from cell supernatant using Protein G affinity chromatography, and used as bait to isolate phage ligands from the C7C phage-displayed peptide library fused to the M13 minor coat protein. ELISA was performed to select ligands with distinct affinities for their cognate Ig-BCR. Synthetic peptides corresponding to the peptide insert of phage clones were assayed for their antigenic properties out of the phage context. The purified 5T33MM-released exosomes were characterized by scanning electron microscopy (SEM), Zetasizer and Western blotting analysis. SMNPs were decorated with biotinylated anti-CD63, incubated with RED-EXO-labeled exosomes, and analyzed for the binding of FITC-conjugated Id-peptides by flow cytometry. For in vivo analysis, 5T33MM cells (1 × 10⁶) were intravenously injected in C57BL/KaLwRij mice (10 females at 8 weeks of age). Tumor-derived exosomes and paraprotein levels in peripheral blood were monitored every 7 days up to 35 days post-inoculation