Surface modified polymeric nanoparticles for immunisation against equine strangles.

The study focuses on developing and characterizing a nanoparticle-based vaccine for equine strangles, a disease in horses caused by the Streptococcus equi bacterium. The researchers used surface modified poly(lactic acid) nanoparticles, with an enzymatic extract of the bacteria adsorbed on their surface. The study also investigates the physical and chemical properties of this absorption process and shows promising results for using this method to create carriers for antigens in future vaccines.

Research Approach and Materials Used

• The researchers utilized poly(lactic acid) (PLA) nanoparticles as a base for their vaccine.
• The nanoparticles were surface modified with three different materials – polyvinyl alcohol (PVA), alginate (ALG), and glycolchitosan (GCS).
• An enzymatic extract of Streptococcus equi, the bacterium that causes equine strangles, was adsorbed onto the surface of the nanoparticles.

Adsorption Process and Findings

• The study found that the adsorption of the S. Equi proteins onto the nanoparticles was a rapid process. Within just an hour, maximum adsorption efficiency levels were achieved; 75.2% for PLA-PVA, 84.9% for PLA-GCS, and 78.1% for PLA-ALG nanoparticles.
• No protein degradation was detected throughout the formulation procedures, which is promising for the stability of the vaccine material.
• Adsorption data suggested a Freundlich-type of equilibrium. This type of adsorption isotherm is used to describe adsorption characteristics of heterogeneous systems.

Desorption Studies and Findings

• Desorption studies revealed a burst release within the first 6 hours, followed by a more sustained release profile for all nanoparticle formulations.
• Surface modification with GCS emerged as particularly effective, as 20% of the protein still remained attached to the particle surface even after 30 days. This may indicate a potential for longer lasting vaccination effects.

Conclusion and Future Implications

• The results of this study suggest that adsorption is a credible alternative for the production of S. equi antigen carriers for vaccination purposes.
• The nanoparticle-based vaccine developed in this study could be a potential solution for combating equine strangles, improving horse health and safety.