[Induction and mechanism study of anti-melanoma immune response by M. tuberculosis Ag85B].

Aim: To study the anti-melanoma immunity efficacy of Ag85B antigen gene therapy in vivo.

Methods: C57BL/6 mice were inoculated s.c. with B16 cells, and 8 days later the mice were inoculated s.c. again with B16 cells (control group 1), B16/pcDNA3 cells (control group 2) or B16/pcDNA3-Ag85B cells (experimental group), respectively. Tumor volume, survival time, serum IFN-gamma level and IL-4 level of 3 groups mice were observed. Antitumor activity of Ag85B was studied.

Results: From 12 to 23 day, the mean tumor volume of mice increased from 1.1058 cm(3) and 0.9123 cm(3) to 7.5983 cm(3) and 5.8746 cm(3) in the control group 1 and 2, respectively. But it increased from 0.5158 cm(3) to 1.5080 cm(3) in the experimental group. The mean survival time of mice was 24.1 days and 24.7 days in the control group 1 and 2, respectively. That was 27.8 days in the experimental group. Within 13 days after the last inoculation, the serum IFN-gamma level of all groups experienced increased (That increased to 26.3 ng/L, 23.0 ng/L and 25.2 ng/L in the control group 1, 2 and the experimental group, respectively). Subsequently, the serum IFN-gamma level in the two control groups decreased (That decreased to 19.3 ng/L and 18.3 ng/L in the control group 1 and 2) while it still augmented in the experimental group (That increased to 46.5 ng/L). IL-4 level was slightly but not significantly enhanced and then declined in all mice.

Conclusion: Ag85B induced the increase of serum IFN-gamma level in the animals experiments, inhibited the tumor growth and prolonged the survival of the tumor-bearing mice.