Antitumor activity of Propionibacterium acnes strain KT-28, an isolate from the oral cavity, was examined by using mice inoculated with meth A cells. Histochemically, it was found that L3T4+ and Lyt2+ T cells invaded the tumor region of mice injected with the protease-treated ultrasonic sediment preparation. And macrophage and NK cells also invaded the tumor region of mice injected with the protease-treated ultrasonic sediment preparation. Furthermore, it was suggested that the antitumor activity might be related to the immune system.
