title: Mammary tumor growth inhibition in C3H/He mice by long-term Bacillus Calmette-Guérin immunoprophylaxis versus enhancement by primary Bacillus Calmette-Guérin therapy.
abstract: The effects of long-term prophylactic use of and the effects of treatments with Bacillus Calmette-Guérin (BCG) and methanol extraction residue of BCG have been compared in C3H/He mice implanted with the immunogenic syngeneic mammary carcinoma MC2. The effect of long-term BCG treatment on the development of spontaneous mammary tumors was also investigated. Enhanced resistance to primary tumor development and MC2 growth was only seen in groups of mice that had received long-term pretreatments with BCG or methanol extraction residue of BCG. A negative effect of BCG treatment on host resistance was seen in animals that were given their first injection of BCG and received their first MC2 implant at the same time. Previous immunization against BCG or against MC2 prevented detectable impairment of host resistance by BCG treatment. These observations suggest that the initial phase of BCG infection may have a negative effect on the development of an immune response against cancer. Prolonged, multidose prophylactic administration of BCG may be required to achieve enhanced protection.
mesh_terms: D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000818:Animals; D001500:BCG Vaccine / Q000627:therapeutic use*; D007167:Immunotherapy; D008325:Mammary Neoplasms, Experimental / Q000503:physiopathology / Q000628:therapy*; D051379:Mice; D008809:Mice, Inbred C3H; D009163:Mycobacterium bovis / Q000276:immunology*; D013997:Time Factors
chemical_list: D000276:Adjuvants, Immunologic; D001500:BCG Vaccine; C011499:methanol extraction residue (MER) tubercle bacillus fraction