Design and Synthesis of Peptides from Phoneutria nigriventer δ-Ctenitoxin-Pn2a for Antivenom Production

The venom toxin δ-ctenitoxin-Pn2a of the spider Phoneutria nigriventer can cause severe envenomation in humans. Furthermore, cystine-knot motif provides exceptional stability, thereby hampering immune response activation. Here we identified epitope G34YFWIAWYKLANCKK48 from through Immune Epitope Database Analysis Resource and used it to design antigenic peptides. Cys residue was replaced by α-aminobutyric acid (Abu) prevent disulfide bond formation. To increase immunogenicity these molecules, branched N-palmitoylated versions were synthesized. Ac-GYFWIAWYKLAN-Abu-KKG-NH2 (A), Palm-GYFWIAWYKLAN-Abu-KKG-NH2 (B) (Ac-GYFWIAWYKLAN-Abu-KK)2-KG-NH2 (C) prepared solid-phase synthesis their identity confirmed ESI–MS. They then studied RP-HPLC all chromatograms obtained showed only one main peak. Cytotoxicity evaluated on murine macrophage cell line RAW 264.7 using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay presence increasing doses each peptide (0.25–10.0 µM). Peptide A did not show cytotoxicity between 0.25 10.0 µM, while B C at concentrations equal or over 0.5 respectively. cellular distribution NF-κB examined immunofluorescence after exposing macrophages µM peptide. Early activation observed for three peptides, indicating that they are promising immunogens antivenom production. Nevertheless, vivo tests still required assess immunogenic capacity whether antibodies generated confer protection against venom.