M Abkar - Department of Molecular Genetics, Faculty of Basic Sciences, Tarbiat Modarres University, Tehran, Iran
A Sahebghadam Lotfi - Department of Clinical Biochemistry, Faculty of Medicine, Tarbiat Modares University, Tehran, Iran
J Amani - Applied Microbiology Research Center, Baqiyatallah University of Medical Science, Tehran, Iran
S Alamian - Brucellosis Department, Razi Vaccine and Serum Research Institute, Karaj, Iran

Brucella (B) species are the causative agents of brucellosis, the world’s most prevalent zoonatic disease. B.melitensis 31 kDa outer membrane protein (Omp31) is a promising vaccine candidate for development of a subunitvaccine against brucellosis. The aim of this study is survey of immunogenicity property of Omp31 with Freund’s adjuvant(Omp31-IFA) or with TMC nanoparticle (TMC/Omp31); investigation of influence of administration routes on immuneresponse polarization and finally how to Omp31 could protect against Brucella species. The Th2 response wassignificantly higher in mice immunized with TMC/Omp31 in Intraperitoneal (i.p.) route whereas the Th1 response wasincreased in Omp31 injection and TMC/Omp31 nanoparticles in oral immunized mice. Moreover, oral immunizationwith TMC/Omp31 nanoparticles increased sIgA levels in fecal and significant production of IL-17 as Th17. Finally, theoral administration of TMC/Omp31 nanoparticles induced the significant high protection level against B. melitensis andB. suis. The results showed that immunization route has a pivotal role in immune response polarization and protectiveefficiency of Omp31 antigen. Also, TMC/Omp31 when administered orally confers more protection level may be due tothe elicited Th17 response.

Brucellosis; Omp31; Oral Vaccine; Nanoparticles