A Comparative Study on the Effect of BCG-PSN and Thymopeptides on T-lymphocyte Subsets of Normal and Immunosuppressed Mice

To compare the effects of polysaccharide nucleic acid fraction of bacillus calmette guerin (BCG PSN) and thymopeptides on T lymphocytes of normal and immunosuppressed mice, CD4 + and CD8 + T lymphocyte subsets of single nucleic cell in thymus, spleen and peripheral blood were detected successively by flow cytometry after application of BCG PSN and thymopeptides. Meanwhile, CD4 +/CD8 + ratio was also calculated. The results showed that both BCG PSN and thymopeptides could decrease the proportion of CD4 + CD8 + T lymphocyte subsets in the thymus, at the same time increase CD4 + T lymphocyte, CD8 +T lymphocyte proportion in the three tissues. The fluctuation in amplitude was greater in thymopeptides group than that in BCG PSN group. It is concluded that acting location of thymopeptides is in thymus, its stimulating action is stronger than that of BCG PSN, while BCG PSN not only accelerates the differentiation in thymus, but also has some direct stimulation to peripheral CD4 +T lymphocytes, and can maintain CD4 +/CD8 + ratio within normal range. So, BCG PSN is safer.

Study of recombinant human IFN-α-2b bacilli Calmette–Guerin activated killer cells and against bladder cancer cell in vitro

Presently,one of the most potent immunothera-pies is the application of bacillus Calmette Guerin(BCG)to prevent recurrences of the superficial bladder cancer.Despite its successful use,nonresponders and certain side effects remain a major obstacle.Therefore,current studies aim at developing recombinant BCG(rBCG)strains secreting Th1-like cytokines to improve the effectiveness of the therapy.In this study,a new type of rBCG strain constructed by Tianjin institute of Urology was tested for its immunostimulatory capacity in vitro.Peripheral blood monocytes(PBMC)were stimulated by recombinant BCG and transformed into bacilli Calmette–Guerin activated killer(BAK)cells,and the effect of anticancer BAK cells was studied.Recombinant IFN-a-2b-BCG,wild-type BCG(wBCG),wild-type BCG and IFN-a-2b were coincubated with PBMCs respectively in vitro,and the proliferation of PBMC was detected with MTT in different time.BAK cells have the ability to kill bladder tumor cells,and the antitumor activity of effecter cells was determined by LDH release assay.The result of MTT showed that the proli-feration of PBMC in the recombinant BCG group was more powerful than in the other two groups(P<0.05).The result of LDH release assay showed that the antitumor activity of BAK cells stimulated by Recombinant BCG was the highest in all groups.We conclude that the recombinant BCG can activate more PBMCs to anti-bladder cancer in vitro than wild-type BCG does.