Nanoparticle and polysaccharide conjugate: a potential candidate vaccine to improve immunological stimuli

Active polysaccharides isolated from various fungal sources have been implicated to stimulate immune response against various pathogens as well as self anomalies such as cancer. Therefore, the nuanced approach presented in our work was to blend polysaccharides derived from Pleurotus ostreatus with biocompatible ferrite nanoparticles and thereafter investigate the enhanced immune functionality of the polysaccharide-nanoparticle composite. A Schiff base reductive amination reaction occurred between the aldehyde group of the polysaccharide and the amine group of the nanoparticles in the presence of a strong reducing agent such as sodium cyanoborohydride to form a stable amide bond between the two conjugating molecules. The multifaceted conjugate was characterized by physiochemical techniques such as electron microscopy, FTIR, VSM and DLS measurements. This particulate form of the polysaccharide showed a marked escalation in the production of free radicals such as reactive oxygen and nitrogen species in murine macrophages as compared to the soluble form. Animal based experiments demonstrated a reduction in tumor volume and augmentation in the proliferation of splenocytes in particulate or conjugated polysaccharide treated mice. Furthermore, molecular signaling studies showed a high upregulation in p-p38 and p-MEK molecules in particulate polysaccharide treated RAW264.7 cells suggesting a cellular downstream mechanistic regulation behind the immunostimulative response.