title: Activation of anti-tumor immune response and reduction of regulatory T cells with Mycobacterium indicus pranii (MIP) therapy in tumor bearing mice.
abstract: BACKGROUND
  Role of immune system in protecting the host from cancer is well established. Growing cancer however subverts immune response towards Th2 type and escape from antitumor mechanism of the host. Activation of both innate and Th1 type response is crucial for host antitumor activity. In our previous study it was found, that Mycobacterium indicus pranii (MIP) also known as M. w induces Th1 type response and activates macrophages in animal model of tuberculosis. Hence, we studied the immunotherapeutic potential of MIP in mouse tumor model and the underlying mechanisms for its antitumor activity.
  
  
  RESULTS
  Tumors were implanted by injecting B16F10 melanoma cells subcutaneously into C57BL/6 mice. Using the optimized dose and treatment regimes, anti-tumor efficacy of heat killed MIP was evaluated. In MIP treated group, tumor appeared in only 50-60% of mice, tumor growth was delayed and tumor volume was less as compared to control. MIP mediated immune activation was analysed in the tumor microenvironment, tumor draining lymph node and spleen. Induction of Th1 response and higher infiltration of immune cells in the tumor microenvironment was observed in MIP treated mice. A large fraction of these immune cells were in activated state as confirmed by phenotypic and functional analysis. Interestingly, percentage of Treg cells in the tumor milieu of treated mice was less. We also evaluated efficacy of MIP along with chemotherapy and found a better response as compared to chemotherapy alone.
  
  
  CONCLUSIONS
  MIP therapy is effective in protecting mice from tumor. It activates the immune cells, increases their infiltration in tumor, and abrogates tumor mediated immune suppression.
authors: Product Development Cell-I, National Institute of Immunology, New Delhi, India.
authors: Faiz
authors: F
authors: Ahmad
authors: Jiju
authors: J
authors: Mani
authors: Pawan
authors: P
authors: Kumar
authors: Seenu
authors: S
authors: Haridas
authors: Pramod
authors: P
authors: Upadhyay
authors: Sangeeta
authors: S
authors: Bhaskar
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000378:metabolism; D007167:Immunotherapy; D007694:Killer Cells, Natural / Q000276:immunology; D008545:Melanoma / Q000378:metabolism / Q000628:therapy; D051379:Mice; D008810:Mice, Inbred C57BL; D009161:Mycobacterium / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse