Lactic acid bacteria can affect the maturation of immune cells and their products not only in the gut but also on the systemic immune organs such as lymph nodes and spleen. In the present work, we studied the effects of oral administration ofLactobacillus acidophiluson the immune responses of BALB/c mice bearing transplanted breast tumour. Two groups of female inbred BALB/c mice, each containing nine mice as test and control, were used. TheL. acidophilusATCC4356 strain was inoculated in DeMan–Rogosa–Sharpe broth and cultivated for 24 h at 37°C. Then, it was collected by centrifugation, and was washed and suspended in PBS. Afterwards, 0·5 ml/d of this suspension, which contained 2·7 × 10⁸ colony forming units/ml of bacteria, was orally administered to the mice by gavage, 14 d before tumour transplantation and 30 d after that with 3-d intervals. Similar to the test mice, the control mice received an equal volume of PBS. The results showed that oral administration ofL. acidophilusincreased the production of IL-12 (P < 0·05) and decreased the level of transforming growth factor β (P = 0·05) in the splenocyte culture. Moreover, the growth rate of tumour in the test mice decreased (P < 0·01), and the results of delayed-type hypersensitivity assay after 48 h were risen (P < 0·05) in comparison with the controls. Results suggest that daily consumption ofL. acidophiluscan improve the production of immunomodulatory cytokine IL-12 in the splenocyte culture, which was stimulated by tumour antigen in BALB/c mice bearing transplanted breast tumour. But further studies are needed to find out some other possible mechanisms of this effect.

Background: The immunomodulative effects of Lactic Acid Bacteria as probiotics have been already demonstrated. Objectives: The current study aimed to evaluate the effect of oral administration of Lactobacillus acidophilus on the immune responses and patterns of cytokine production in the BALB/c mice bearing breast cancer. Materials and Methods: The current study used thirty inbred BALB/c mice, six- to eight-week-old; they were divided into two groups of 15 each. One group was used as control in each assay. The L. acidophilus (ATCC4356) used in the study was inoculated in MRS broth and cultivated overnight at 37°C under anaerobic conditions, then collected by centrifugation, and re-suspended in Phosphate-buffered Saline (PBS) media. After preparation of the proper amount of the suspension, it was orally administered to the mice via gavage and the control mice received an equal volume of PBS in the same manner. Results: The results showed that oral administration of L. acidophilus as a potent immunostimulator agent could motivate the proliferation of immune cells. Moreover, it could increase the production of IFN-γ and decrease the production of IL-4, known as Th2 cytokines, in the spleen cell culture. The results showed that the survival time of the L. acidophilus administered mice significantly increased in comparison to that of the control mice. Conclusions: The current study findings suggested that L. acidophilus can promote immune responses with Th1 bias and may increase the antitumor response. Further, the consumption of this probiotic strain may help to manage the immune response in tumor condition, but more studies are needed to investigate the other mechanisms of this effect. Keywords: Lactobacillus acidophilus; Breast Cancer; IFN-γ; Immunomodulation

In recent years, the increasing resistance of enteropathogenic Escherichia coli (EPEC) to commonly used antibiotics has made it difficult to choose the best treatment option. Bacteriophage therapy could be a potent alternative to antibiotic therapy for antibiotic-resistant bacteria. The aim of the present study was to isolate and identify a specific bacteriophage against EPEC and characterize bacteriophage in vitro and in vivo. The specific bacteriophage was isolated, and the effect of phage therapy on 48 mice (Balb/c) was investigated. Animals were divided into six groups, including A: PBS (negative control); B: bacteria (positive control); C: bacteria + ciprofloxacin (after 24 h); D: bacteria + bacteriophage (after 24 h); E: bacteria + ciprofloxacin + bacteriophage (after 24 h) and F: bacteriophage + bacteria (after 24 h). Specific bacteriophage against EPEC was isolated from hospital sewage. The bacteriophage had an icosahedral head (120 nm) and a tail (138 nm). The single dose of the bacteriophage (2 × 10⁹ pfu ml⁻¹) was able to control the infection. Unfortunately, because of the misuse of antibiotics by EPEC infected patients, the antibiotic resistant bacteria will become prevalent in the future and the treatment of EPEC infection is going to become more difficult than ever.