Evaluation of immuno-modulating effect of recombinant heat shock protein 40 of Brucella abortus in mice

The present study was aimed to evaluate the immuno-modulatory effect of Brucella-specific recombinant HSP40 (rDnaJ) when co-immunized with Brucella rOmp22 in mice. For this, dnaJ of Brucella abortus was cloned, expressed in E. coli, and purified to homogeneity using Ni–NTA agarose columns. Three groups of mice (n = 6 in each group) were used in the study. The control group was immunized with rOmp22 alone, while group 1 mice were injected subcutaneously with rOmp22 along with conventional adjuvants (FCA, FIA), and group 2 mice with rOmp22 mixed with rDnaJ. IgG isotype (IgG1 and IgG2a) response to rOmp22 immunization was evaluated by enzyme-linked immunosorbent assay which was found to be directed towards the cell-mediated arm of immune system (CMI) in group 2 mice in which rOmp22 was co-immunized with rDnaJ. Expression profiling of IL-4 and IL-12 was checked in all the groups by qRT PCR. IL12 mRNA was up-regulated to a greater extent in group2 mice, suggesting that the CMI arm of immune system was stimulated. Hence, it was concluded that CMI response against rOmp22 is stimulated to a greater extent in mice when co-immunized with Brucella rDnaJ.