Nanovaccine for leishmaniasis: preparation of chitosan nanoparticles containing Leishmania superoxide dismutase and evaluation of its immunogenicity in BALB/c mice

Mohammad Ali Danesh-Bahreini^1,5, Javad Shokri^1,2, Afshin Samiei³, Eskandar Kamali-Sarvestani⁴, Mohammad Barzegar-Jalali¹, Soliman Mohammadi-Samani^4
1Department of Pharmaceutics, ²Research Center for Pharmaceutical Nanotechnology, School of Pharmacy, Tabriz University of Medical Science, Tabriz, Iran; ³Autoimmune Diseases Research Center, School of Medicine, ⁴Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Science, Shiraz, Iran; ⁵Research and Development Department, Exir Pharmaceutical Company, Borujerd, Iran

Background: Leishmaniasis is a protozoan disease, affecting 12 million people in different regions of the world with a wide spectrum of diseases. Although several chemotherapeutic agents have been used for treating the disease, long-term therapy, limited efficacy and the development of drug-resistant parasites remain the major limitations.
Methods: To develop a new nanovaccine for leishmaniasis, recombinant Leishmania superoxide dismutase (SODB1) was loaded onto chitosan nanoparticles by the ionotropic gelation method. Size and loading efficiency of the nanoparticles were evaluated and optimized, and an immunization study was undertaken on BALB/c mice. The mice received phosphate buffer saline (PBS), superoxide dismutase B1 (SODB1) in PBS and nanoparticles via subcutaneous injection. Soluble Leishmania Antigens (SLA) and complete Freund’s adjuvant (CFA) were also injected subcutaneously three times every three weeks (some groups received only a single dose). Three weeks after the last injection, blood samples were collected and assessed with ELISA to detect IgG2a and IgG1.
Results: Immunological analysis showed that in single and triple doses of SODB1 nanoparticles, IgG2a and IgG2a/IgG1 were significantly higher than the other groups (P<0.05).
Conclusion: The results revealed that formulations of SODB1 in biodegradable and stable chitosan nanoparticles can increase the immunogenicity toward cell-mediated immunity (T_H1 cells producing IgG2a in mice) that is effective in Leishmania eradication and could be presented as a single dose nanovaccine for leishmaniasis.

Keywords: chitosan nanoparticles, leishmaniasis, vaccine, superoxide dismutase