DISEASE CHARACTERISTICS:

• Histologically confirmed metastatic adenocarcinoma of the prostate

  • Stage D1-3
  • Regional lymph node, bone, visceral, or soft tissue metastases
  • No transitional cell or small cell carcinoma
• Testosterone less than 50 mg/L if prior treatment with luteinizing hormone releasing hormone (LHRH) analogues or estrogens
• Evidence of androgen refractory disease after surgical castration and discontinuation of LHRH analogue therapy
• No previously irradiated or new CNS metastases

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 70-100%

Life expectancy:

• More than 6 months

Hematopoietic:

• WBC at least 3,000/mm^3
• Hemoglobin at least 9 g/dL
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin less than 2.0 mg/dL
• PT at least 11.3 seconds but no greater than 13.3 seconds
• PTT at least 20.1 seconds but no greater than 32.9 seconds
• No hepatic disease
• No viral hepatitis

Renal:

• Creatinine less than 2.5 mg/dL

Cardiovascular:

• No New York Heart Association class III or IV heart disease

Pulmonary:

• No asthma
• No chronic obstructive pulmonary disease
• No severe lung disease

Other:

• No other medical illness or psychological impediment that would preclude study
• No other concurrent malignancy except nonmelanoma skin cancer or controlled superficial bladder cancer
• No active acute or chronic infection including symptomatic urinary tract infection
• No autoimmune disease (e.g., inflammatory bowel disease, systemic lupus erythematosus, rheumatoid arthritis, ankylosing spondylitis, scleroderma, or multiple sclerosis)
• HIV negative
• Adequate peripheral vein access

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Prior biologic therapy allowed
• No other concurrent immunotherapy

Chemotherapy:

• Prior chemotherapy allowed
• No concurrent chemotherapy

Endocrine therapy:

• See Disease Characteristics
• At least 4 weeks since prior non-steroidal hormonal therapy if increase in PSA while receiving non-steroidal hormonal therapy
• At least 6 weeks since prior steroids
• Concurrent LHRH analogues for gonadal androgen suppression allowed
• No concurrent steroid therapy
• No concurrent corticosteroids

Radiotherapy:

• See Disease Characteristics
• Prior palliative radiotherapy for bone metastases allowed
• Prior prostatic radiotherapy allowed
• At least 4 weeks since prior radiotherapy
• At least 12 weeks since prior strontium chloride Sr 89
• No concurrent radiotherapy

Surgery:

• See Disease Characteristics

Other:

• Recovered from prior therapy
• No concurrent immunosuppressive agents (e.g., azathioprine or cyclosporine)