Nanovaccine for brucellosis: multi epitope subunit vaccine- loaded mannosylated chitosan nanoparticles induce high protection against brucella infection

Zohre Sadeghi,1 Mahdi fasihi ramandi,2 Saeid bouzari,3,*

1. Pasteur Institute of Iran
2. Baqiyatallah University of Medical Sciences
3. Pasteur Institute of Iran



Brucellosis is a zoonotic disease that can cause abortion in domestic animals and severe disease in humans. brucellosis exhibited as an endemic disease in iran. live attenuated brucella vaccines have several drawbacks. peptide-based vaccines have been advocated as an attractive approach for prevention or treatment of infectious diseases. the reverse vaccinology has introduced new candidates for brucella such as bhua, flic, 7α- hsdh through computer analysis. chitosan nanoparticles also play an important role in enhancing acquiring immune responses. therefore, in this study, we try to test novel multi-epitope subunit vaccines with mannosylated chitosan nanoparticles against brucellosis infection in mouse model.


B cell and cd4+ and cd8+t cell epitopes from bhua, flic, 7α-hsdh antigens were selected and arranged in different patterns. the two and three-dimensional structure of the constructs were evaluated. then, expression of the synthetic constructs were performed using pet28a expression vector in e. coli bl21(de3). the proteins were purified with ni-nta column. sds-page and western blot were used for confirmation of purified proteins. mannosylated chitosan nanoparticles are synthesized by chemical synthesis and then nanoparticles are examined in terms of structure, shape and size by ftir, sem and dls. mice were immunized and cytokines ifn-γ, il-2, il-10 level and total igg, igg1 and igg2a antibodies were assessed by elisa. in challenging tests different groups of immunized mice were infected with brucella.


According to our in silico analyses, b and t constructs were stable with high antigenicity and immunogenicity. sds-page and western blotting results indicated the similarity of in silico designing and in vitro expression. vaccination of balb/c mice with the nanovaccine candidates provided strong humoral and cellular immune responses and protected the mice from b. melitensis and b. abortus challenge.


In conclusion, these recombinant nanovaccine candidates could generate a potent immune response and may be used as epitope-based vaccine for development of brucella vaccine candidates.


Brucella, multi-epitope vaccine, new candidate, chitosan, nanovaccine