Tropical Journal of Pharmaceutical Research

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Induction of protective immune responses in mice by double DNA vaccine encoding of Brucella melitensis Omp31 and Escherichia coli Eae genes

Reza Ranjbar, Samanehsadat Sharifimoghadam, Elnaz Saeidi, Nematollah Jonaidi, Amirhossein Sheikhshahrokh


Purpose: To investigate the efficacy of a double DNA vaccine encoding of Brucella melitensis omp31 gene and of Escherichia coli eae gene in inducing protective immune response in a mouse model.

Methods: After performing PCR assays and cloning both the eae and omp31 genes, the generated DNA vaccines were intramuscularly injected into BALB/c mice. Purified proteins and transformed cell lysates were identified by western blot and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by enzyme-linked immunosorbent assay (ELISA).

Results: pcDNA3-omp31-eae provokes a significant, high level of protection in BALB/c mice against challenges with E. coli and B. melitensis. Titers ranging from 90:160 to 2,570:5,110 were detected 60 days after vaccination. Notably, rOmp31 and rEae proteins significantly induced the production of IFN-γ in cells from pcDNA3-omp31-eae-immunized mice (p < 0.05 in both groups) and only low levels of IL-10 were found in all groups. The lymphocytes from mice immunized with pcDNA3-omp31-eae had an apparent T cell proliferative response to rOmp31 and rEae proteins (p < 0.01) with a stimulation index of 14.90.

Conclusion: The novel pcDNA3-omp31-eae construct can be used as a DNA vaccine to prevent E. coli and B. melitensis infections in future studies.

Keywords: Multiple DNA vaccine, Omp31 gene, Brucella melitensis, Eae gene, Escherichia coli, Protective immune response
AJOL African Journals Online