Survey of Omp19 immunogenicity against Brucella abortus and Brucella melitensis: influence of nanoparticulation versus traditional immunization

Abstract

Brucellosis is the most common zoonotic bacterial disease. Prevention of human brucellosis is achieved through pasteurization of dairy products, appropriate sanitation and vaccination of domestic animals against the Brucella species. B. abortus unlipidated 19 kDa outer membrane protein (U-Omp19) is a promising candidate for a subunit vaccine against brucellosis. This study investigates immunogenicity of Omp19 alone and with Freund's adjuvant (Omp19-IFA) and N-trimethyl chitosan (TMC/Omp19) nanoparticles, as well as the effect of Omp19 administration route on immunological responses and protection. The omp19 gene was expressed in E. coli BL21 (DE3). After purification, the recombinant Omp19 was loaded onto TMC nanoparticles by ionic gelation with tripolyphosphate. Particle size and loading efficiency of the nanoparticles were determined. Omp19-IFA was administered intraperitoneally while TMC/Omp19 nanoparticles were administered orally and intraperitoneally. The results indicated that intraperitoneal (i.p.) immunization by Omp19-IFA and TMC/Omp19 nanoparticles induced Th1 and Th2 immune responses, respectively, whereas oral immunization of TMC/Omp19 nanoparticles induced a mixed Th1/Th17 immune response. Moreover, oral immunization increased IgA levels in feces. Immunized mice were challenged with virulent B. melitensis 16 M and B. abortus 544. Oral immunization with TMC/Omp19 nanoparticles induced a remarkably high protection level against B. melitensis and B. abortus. The results showed that immunization route has a pivotal role in immune response polarization and protective efficiency of Omp19 antigen. Also, it was deduced that the higher protection level achieved through oral administration of TMC/Omp19 nanoparticles may be due to the elicited Th17 response.

Oral immunization of mice with Omp31-loaded <em>N</em>-trimethyl chitosan nanoparticles induces high protection against <em>Brucella melitensis</em> infection

“…We showed that oral administration of TMC/ Omp31 NPs induces a significant cellular-mixed Th1-Th17 immune response that is in accordance with the observations by Pasquevich et al 36 and Abkar et al 44 that had shown that oral administration of another antigen (plant-expressed Omp19) and TMC/Omp19 elicits a significant cellular-mixed Th1-Th17 immune response. In a study conducted by Abkar et al, oral vaccination with TMC/Omp19 induced immune responses and a high level of protection against systemic infection.…”

Novel application of trimethyl chitosan as an adjuvant in vaccine delivery

“…63 Higher protection against Brucella melitensis and Brucella abortus infection was observed by oral route immunization in mice with TMC NPs encapsulating Omp19 as well as Omp31 than the intraperitoneal route. 77,78 The intraduodenal route of administration was also verified by a group by administration of TMC NPs encapsulated OVA as antigen and led to significantly higher antibody rise than antigen alone. 79 Several groups also explored the dermal route.…”

In silico designing, cloning, and heterologous expression of novel chimeric human B lymphocyte CD20 extra loop

“…The pET-CD20EXL was transformed into E. coli BL21 (DE3) strain (Novagen Co.), and transformed clones were evaluated for recombinant protein expression as described previously [22]. Briefly, suitable clone with high level expression inoculated LB medium containing kanamycin (50 μg/ml), and the culture was grown under agitation overnight at 37°C till having 0.5 optical density (OD) value at 600 nm.…”