Recombinant Mycobacterium bovis BCG expressing chimaeric protein of Ag85B and ESAT-6 enhances immunostimulatory activity of human macrophages.

Recombinant BCG strain that secretes the chimaeric protein of Ag85B and ESAT-6 has been demonstrated to augment Th1 immune response in C57BL/6 mice. In this paper, we studied the immunostimulatory activity of the recombinant BCG strains in vitro and found out that rBCG-A(N)-E-A(C) activated THP-1 cells and induced higher expression levels of CD86, CD80, CD40 and HLA-DR, especially increased the ratio of CD86/CD80. Likewise, rBCG-A(N)-E-A(C) infection was able to stimulate an increase in TNF-alpha production of macrophages. Moreover, rBCG-A(N)-E-A(C) up-regulated the expression of EFHD2, ACTB and ACTG1 in the macrophages and improved the ability of antigen presentation and the CD8(+) T-cells immune response. Taken together, this rBCG-A(N)-E-A(C) strain enhanced the immunostimulatory activity of human macrophages and could be a potential vaccine against Mycobacterium tuberculosis.