Effect of oral administration of different combinations of killed bacteria on some depressed macrophage functions in tumor-bearing rats.

In the present study, we compared the ability of different bacterial species administered orally in various combinations to restore some depressed peritoneal macrophage functions in tumor-bearing rats. Phagocytosis, killing of Candida albicans and chemotactic response of resident peritoneal cells from treated tumor-bearing rats were influenced by different associations of bacteria. In particular, when Staphylococcus aureus was administered together with other bacterial species, the phagocytic activity of peritoneal cells was restored to normal values, and intracellular killing of C. albicans was enhanced. The results are discussed in relation to the possible influence of mucosal bacterial flora on the level of activation of peritoneal macrophages. The possibility that bacterial species can influence in various ways immunocompetent cells in relation to the different chemical composition of some common structures is also discussed.