The experiment of immunological effect of Ag85A and Ag85B DNA vaccine on bladder tumor

Objective To explore the immunological effect of Ag85A,Ag85B and Ag85A+ Ag85B DNA vaccine on bladder cancer.Methods Female Wistar rats aged 6-8 weeks were served as experimental animals.Bladder tumor in situ model was established by bladder irrigation of MNU.Implanted bladder tumor model was established by subcutaneously injecting BTT739 cell strain in rear limb.Selected randomly 10 rats were killed at fourteenth day after end-irrigation to identify if successful for the models.The Wistar rats of each model group were randomly assigned to 6 subgroups(n=8 each): normal saline group(NS group),pcDNA3.1 group(blank plasmid group),pcDNA3.1-Ag85A group(Ag85A group),pcDNA3.1-Ag85B group(Ag85B group),pcDNA3.1-Ag85A+Ag85B group(combined group) and BCG vaccine group(BCG group).The vaccination was performed at seventh,fourteenth and twenty-first day in all experimental rats for observing immunological effect.T cell subgroups of spleen tissue were analyzed;levels of serum IFN-γ were detected;tumor inhibition rate of tumor-bearing rats was calculated;histopathological examination of stripped tumor was performed.Results The models of bladder tumor in situ and in implanted cancer were successfully established.The tumor inhibition rate were 63.53%,53.56%,33.08%,11.50% and 1.10%,respectively,in BCG group,combined group,Ag85B group,Ag85A group and blank plasmid group.Besides the blank plasmid group,the number of CD4+ and CD8+ T cell subsets,the ratio of CD4+/CD8+ and IFN-γ level in each group were significantly higher than that in NS group(P0.05 or P0.01).Pathological observation demonstrated that tumor necrosis was obvious in BCG group,combined group and Ag85B group,but was not in other three groups.The immunological effects of BCG group were the highest in all groups.Conclusions Ag85A and Ag85B DNA vaccine have stronger immunization effects on situ and implanted bladder tumor.Immunization effect of Ag85A DNA vaccine is lower than Ag85B DNA vaccine,and synergetic effect after joint application is more predominant,but no matter Ag85A DNA,Ag85B DNA or their joint application could not be compatible with BCG.