Immunostimulatory effect of tetanus toxoid loaded chitosan nanoparticles following microneedles assisted immunization.

The present study investigated potential of tetanus toxoid loaded chitosan nanoparticles (TT-Ch-NPs) following bare topical and microneedles assisted immunization. The TT-Ch-NPs were prepared by ionotropic gelation method using poly(sodium-4-styrene sulfonate) (PSS) as crosslinking agent which exhibited ~208 nm size and ~99% entrapment efficiency. The manufacturing process did not have any detrimental effect on integrity and conformation of antigen. The in vitro analysis demonstrated higher skin penetration following microneedles assisted immunization. In vivo immunization studies exhibited that TT-Ch-NPs delivered through microneedles induced comparable IgG and IgG1 titer, yet higher IgG2a titer than commercial TT vaccine. Similarly, microneedles assisted administration of TT-Ch-NPs generated higher Th1 cytokines, albeit no significant alteration in Th2 cytokines levels than commercial TT vaccine. In conclusion, microneedles assisted administration of TT-Ch-NPs especially via hollow microneedles (HMN) could be considered as best preferred route for immunization due to induction of more balanced Th1/Th2 biased immune response. From the Clinical Editor: The use of skin as a route for vaccination has been a clinically important topic for some time. In this article, the authors investigated the efficacy of both solid microneedles and hollow microneedles as methods for topical delivery of tetanus toixoid. The positive finding in the experiments could provide a better method for vaccination in the clinical setting in the future.

Development of dual toxoid-loaded layersomes for complete immunostimulatory response following peroral administration.

AIM: Present study reports the development of divalent vaccine with enhanced protection, permeation and presentation following peroral immunization. MATERIALS & METHODS: Layersomes were prepared by layer-by-layer tuning of polyelectrolytes on liposomes template. The developed system was evaluated for in vitro stability of antigen and layersomes, cell-based assays and immunization experiments in mice. RESULTS: Layersomes exhibited enhanced stability in simulated biological fluids, still preserving the integrity, biological activity and conformational stability of toxoids. Layersomes also exhibited complete and protective (>0.1 IU/ml) immunostimulatory response include serum IgG titer, mucosal sIgA titer and cytokines (IL-2 and IFN-γ) levels following peroral administration. CONCLUSION: The positive findings of proposed strategy are expected to contribute significantly in the field of stable liposomes technology and peroral immunization.

Divalent toxoids loaded stable chitosan-glucomannan nanoassemblies for efficient systemic, mucosal and cellular immunostimulatory response following oral administration.

The present study reports dual tetanus and diphtheria toxoids loaded stable chitosan-glucomannan nanoassemblies (sCh-GM-NAs) formulated using tandem ionic gelation technique for oral mucosal immunization. The stable, lyophilized sCh-GM-NAs exhibited ~152 nm particle size and ~85% EE of both the toxoids. The lyophilized sCh-GM-NAs displayed excellent stability in biomimetic media and preserved chemical, conformation and biological stability of encapsulated toxoids. The higher intracellular APCs uptake of sCh-GM-NAs was concentration and time dependent which may be attributed to the receptor mediated endocytosis via mannose and glucose receptor. The higher Caco-2 uptake of sCh-GM-NAs was further confirmed by ex vivo intestinal uptake studies. The in vivo evaluation revealed that sCh-GM-NAs posed significantly (p<0.001) higher humoral, mucosal and cellular immune response than other counterparts by eliciting complete protective levels of anti-TT and anti-DT (~0.1 IU/mL) antibodies. Importantly, commercial 'Dual antigen' vaccine administered through oral or intramuscular route was unable to elicit all type of immune response. Conclusively, sCh-GM-NAs could be considered as promising vaccine adjuvant for oral mucosal immunization.