title: Prolongation of the survival time of tumor-bearing mice treated with penicillins alone or in combination with living bacteria.
abstract: Relatively high doses (100 approximately 250 mg/kg) of penicillins such as sulbenicillin and ampicillin prolonged the survival time of C57BL/6 mice bearing EL-4 tumor when they were given 2 days after subcutaneous implantation of the tumor. This activity of penicillins was small but consistent under these conditions. These penicillins had little influence on lymphocytic functions or antibody production of normal and tumor-bearing mice. Therefore, the activity of penicillins to prolong the survival time of mice with a small tumor burden was assumed to be due to an enhanced host resistance elicited by certain indigenous bacterial flora susceptible to penicillins. This view was supported by the findings that artificial infection with gram-positive cocci in combination with treatment with penicillins considerably prolonged the survival time of mice with an early EL-4, while similar treatment did not improve the survival time of mice with growing tumors. Most gram-negative bacteria, which proliferated systemically and did not remain in the local region, were ineffective.
mesh_terms: D000818:Animals; D001419:Bacteria / Q000276:immunology*; D001424:Bacterial Infections / Q000276:immunology; D007113:Immunity, Innate / Q000187:drug effects*; D007167:Immunotherapy; D008228:Lymphoma, Non-Hodgkin / Q000276:immunology / Q000401:mortality / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D010406:Penicillins / Q000008:administration & dosage* / Q000494:pharmacology; D012513:Sarcoma, Experimental / Q000401:mortality / Q000628:therapy; D013997:Time Factors
chemical_list: D010406:Penicillins