Immunotherapy in Treating Patients With Metastatic Breast Cancer

DISEASE CHARACTERISTICS: Histologically confirmed metastatic breast cancer that expresses carcinoembryonic antigen (CEA) At least 25% of the tumor cells must stain positive for CEA with at least moderate intensity Must have achieved either partial response or complete response after high dose chemotherapy and peripheral blood stem cell transplant Hormone receptor status: Not specified PATIENT CHARACTERISTICS: Age: 18 and over Menopausal status: Not specified Performance status: Karnofsky 70-100% Life expectancy: Greater than 6 months Hematopoietic: Absolute neutrophil count at least 1000/mm^3 Absolute lymphocyte count at least 1000/mm^3 Hemoglobin at least 9 mg/dL Platelet count at least 100,000/mm^3 Hepatic: Bilirubin less than 2.0 mg/dL No serious ongoing chronic or acute hepatic disease Renal: Creatinine less than 2.5 mg/dL Cardiovascular: No serious ongoing chronic or acute cardiac disease (New York Heart Association class III or IV) Pulmonary: No serious ongoing chronic or acute pulmonary illness such as asthma, chronic obstructive pulmonary disease, or radiation or drug induced pneumonitis Other: No other prior or concurrent malignancy except nonmelanoma skin cancer or controlled superficial bladder cancer within the past 5 years No history of autoimmune disease such as inflammatory bowel disease, systemic lupus erythematosus, rheumatoid arthritis, ankylosing spondylitis, scleroderma, or multiple sclerosis No inflammatory bowel condition such as active infectious enteritis or eosinophilic enteritis No active acute or chronic infection such as urinary tract infection, HIV, or viral hepatitis Not pregnant or nursing PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics No concurrent immunotherapy Chemotherapy: See Disease Characteristics No concurrent chemotherapy Endocrine therapy: At least 4 weeks since steroids No concurrent steroid therapy Radiotherapy: No concurrent radiotherapy Surgery: Not specified Other: No concurrent immunosuppressive agents such as azathioprine or cyclosporine A