Immunogenicity of a combination of polylactic nanoparticles of co-glycolic acid and chitosan with PRP of Haemophilus influenzae as a nanovaccine in an animal model

The use of nanoparticles is one of the newest methods of making vaccines. Nano-vaccines based on biodegradable polymers produce stronger immune system responses. The aim of this study was to design a Haemophilus influenzae type b nanovaccine in an animal model.

In this study, PRP of Haemophilus influenzae was loaded in the structure of PLGA-Chitosan nanoparticles. Confirmation of AFM, FT-IR size and charge, percentage of release and loading of antigens from the structure of nanoparticles were calculated and the toxicity and antigenicity of nanovaccines were tested by ELISA method. Four groups of female mice were selected and grouped for vaccination. Vaccination and blood sampling were performed from mice’s heart and serum samples were collected and antibody responses against PRP were measured for total IgG and IgM. Pathological examination was performed to evaluate the extent of tissue damage.

Increasing the particle size from 167 ± 47.3 to 209 ± 4.2 and AFM electron microscope images before and after antigen loading showed the success of antigen encapsulation in the nanoparticle structure with 78% efficiency. The results of ELISA and vital organ pathology showed an increase in the titer of total IgG and IgM antibodies in the HIB nanovaccine compared to PRP and the lack of toxicity of the nanovaccine in the vital organs of mice.

The results indicate that resulting nanovaccine has far more absorption and immunogenicity and can act as an effective vaccine against Haemophilus influenzae type b diseases.