RESUMO
OBJECTIVE: To compare the immuno-protection induced by the recombinant BCG vaccine of Toxoplasma gondii GRA4 gene (rBCG-GRA4) and SAG2 gene (rBCG-SAG2) in BALB/c mice. METHODS: 108 SPF BALB/c mice were divided into 6 groups: PBS, BCG, rBCG, rBCG-GRA4, rBCG-SAG2 and rBCG-GRA4+SAG2, each with 18 mice. Each mouse was injected by 100 microl corresponding materials for 2 times. Blood was taken from tail vein before inoculation. 4,6 and 8 weeks after inoculation, spleen was moved and blood was taken from orbit vein of 3 mice from each group for the detection of cytokines, IgG and IgM antibodies, T lymphocyte subgroups and transformation efficiency. 3 weeks after the last inoculation, 9 mice from each group were challenged intraperitoneally with 50 tachyzoites of T. gondii RH strain and their survival time was observed. RESULTS: rBCG vaccine of T. gondii induced immune response. The value of CD3+ CD4+/CD3+CD8+ of group BCG-GRA4+SAG2 was the highest (14.06+/-1.17) in the 4th week; the IgG titer in the BCG-GRA4+SAG2 group was the highest (0.18+/-0.02) in the 6th week and the IgM titer in the BCG-SAG2 group was the highest (0.82+/-0.05) in the 8th week. The average survival time of the mice in BCG-SAG2 group was about 8.61 days after challenged with tachyzoites, and that of the PBS control group, 7.33 days. The average survival time in the 3 immunized groups was one day longer than that of the control. CONCLUSION: The rBCG vaccine of T. gondii shows certain immuno-protection in mice.