Tehran University Medical Journal

Background: In according to immunomodulatory effect of probiotics and effect of these bacteria on the effectiveness of immune responses, at the present work we proposed the evaluation of oral administration of L.acidophilus on the immune statues in BALB/c mice bearing breast cancer.
Methods: A total of 30 In-bred BALB/c mices aged from six to eight weeks weighting 25-30g were randomly enrolled in our study, in two groups each consist of 15 mices. The L.acidophilus ATCC4356 strain used in this study was inoculated in MRS broth and cultivated for a day at 37°^C under anaerobic conditions, collected by centrifugation and resuspend in Phosphate Buffer Saline (PBS). After preparation of proper amount of these suspensions it was orally administered to the mice with a gastric feeding, Control mices received an equal volume of PBS in duration of study.
Results: Results showed the increase in production of IFnγ (p<0.005), and decrease in production of Th2 cytokines such as IL4 (p=0.347) in the L.acidophilus administered mice in comparison to control group of mice. In addition the proliferation of immune cells in probiotic group was significantly higher than controls, and most importantly probiotic administered mice showed an increase in survival rate of this group compared to control mice (p<0.001).
Conclusion: Results of our study suggested that daily consumption of Lactobacillus acidophilus can regulate immune responses skewed Th1 balance that is needed against tumor, further studies is needed to investigate the other mechanisms of this effect.