Anti-tumour research of recombinant BCG using BZLF1 and hGM-CSF fusion genes

After mice were injected with rBCG (recombinant BCG), antibody levels were detected using ELISA, and spleen cells were obtained and the killing rates of specific CTLs by rBCG were detected using a CTL assay kit. Then, the influence of rBCG on tumour cells was analysed in C57BL/6 mice. We found that rBCG-secreting cytokines hybridized with hGM-CSF and BZLF1 antibodies and that the rBCG vaccine stimulated antibody production in C57BL/6 mice. The specific cytotoxic effects of the spleen cells from the rBCG group on EB virus-positive tumour cells was significantly different from the cytotoxic effects of the control group cells (P < 0.01). CD8+ T and CD4+ T lymphocytes were detected in the tumour tissues of the rBCG group mice by flow cytometry, indicating that CD8+ T and CD4+ T lymphocytes infiltrated into the tumour tissue in the mice. Morphological observations of the tumour sections from the rBCG-immunized mice showed the infiltration of lymphocytes into the tumour tissues. The average rBCG tumour volume was less than the average tumour volume of the control group. Thus, rBCG may inhibit the growth of EB virus-positive tumour cells in mice.