C-CfTXA-STxB chimeric antigen loading in PLA-PEG-PLA tri-block copolymers and its immunization in mice

The venom of Jellyfish venom contains a variety of bioactive proteins that can be studied for vaccine application. Poly-Lactic Acid is a biodegradable polymer that is used in vaccine systems. The aim of this study was to encapsulate the C-CfTX1-STxB protein into PLA-PEG-PLA three-block copolymer and its immunogenicity study in mice.

After purification, the protein was confirmed by Western Blot. Then, the antigen was loaded in the three-block copolymer using the solvent evaporated method and prepared nanoparticles characteristics by SEM electron microscopy and DLS. Following encapsulated and free antigen with complete and incomplete adjuvant, PBS and PLA_PEG-PLA nano were injected subcutaneously into the mice four times. In the end, the amount of antibody produced was measured by indirect ELISA and the survival of immunized animals against challenges by jellyfish venom was studied.

The results showed that the prepared nanoparticles have good quality and quantity. The size of the nanoparticles was 176.1 nm and the protein encapsulation efficiency was 71%. In the end, it was shown that immunized mice survived the challenge with the venom and the production of antibody titers was directly related to laboratory animal resistance.

Regarding the lack of cardiotoxicity and neurotoxicity of the recombinant C-CfTX1-STxB protein, as well as the results, PLA-PEG-PLA nanoparticles could be suggested as suitable carriers for the preparation of a vaccine against jellyfish venom for further investigation.