Macrophage and T lymphocyte content of tumors in mice treated with Propionibacterium

Macrophage and T lymphocyte content of sarcoma tumors in mice treated with Propionibacterium granulosum (PG) by different routes was investigated and compared with the effectiveness of the therapy. Two different methods for tumor macrophage detection, the Fc receptor analysis and phagocytic properties, were employed. Indirect fluorescent staining of theta-antigen on lymphocytes was used to evaluate the proportion of tumor T cells. Systemic treatment with PG appeared to be effective if given soon after tumor implantation; however, this route of administration failed to affect the tumor growth if given when the tumor was already advanced. The therapeutic efficiency of intralesional PG injection was almost as effective as early systemic treatment. We obtained evidence indicating that effectiveness of PG therapy was associated with an increase of the macrophage and T cell content of tumors.