DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the prostate

  • Evidence of androgen-independent disease

    • Patient must have received prior primary hormonal therapy (e.g., orchiectomy or gonadotropin-releasing hormone analog with or without antiandrogen)

    • Demonstrated disease progression by any 1 of the following:

      • Elevated PSA level (at least 5 ng/mL) that has serially risen from baseline on 2 occasions at least 1 week apart
      • At least 1 new osseous lesion on bone scan
      • More than 25% increase in the sum of the products of the perpendicular diameters of all bidimensionally measurable sites of disease
• No CNS metastases

PATIENT CHARACTERISTICS:

Age:

• Not specified

Performance status:

• ECOG 0-1

Life expectancy:

• At least 3 months

Hematopoietic:

• Not specified

Hepatic:

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• SGPT no greater than 1.5 times ULN
• Hepatitis B surface antigen negative
• No active or chronic hepatitis B or C
• No other hepatic dysfunction that would preclude study

Renal:

• Creatinine less than 2.0 mg/dL
• Calcium less than 11 mg/dL
• No renal dysfunction that would preclude study
• No symptomatic hypercalcemia

Cardiovascular:

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

Pulmonary:

• No pulmonary disease requiring inhaled steroids or bronchodilators

Other:

• No history of HIV 1 or 2 or human T-cell lymphotrophic virus (HTLV) 1 or 2
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer
• No history of autoimmune disease (e.g., rheumatoid arthritis or multiple sclerosis)
• No other major organ system dysfunction
• No gastrointestinal, neurologic, or psychiatric dysfunction that would preclude study
• Human anti-mouse antibody negative

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent growth factors, interleukin, interferons, or cytokines

Chemotherapy:

• No prior chemotherapy or other systemic chemotherapy agent for prostate or any other cancer

Endocrine therapy:

• Prior aminoglutethimide allowed
• At least 4 weeks since prior flutamide
• At least 6 weeks since prior bicalutamide or nilutamide
• Concurrent luteinizing hormone-releasing hormone agonists should be continued
• No concurrent corticosteroids or dexamethasone
• No concurrent anti-androgens (e.g., flutamide, bicalutamide, or nilutamide)

Radiotherapy:

• At least 4 weeks since prior local radiotherapy
• No prior radiopharmaceutical therapy (e.g., strontium chloride Sr 89 or samarium Sm 153 lexidronam pentasodium)
• No concurrent radiotherapy

Surgery:

• Not specified

Other:

• Prior ketoconazole or PC-SPES allowed
• At least 1 week since prior antibiotic, antifungal, or antiviral agents
• At least 4 weeks since other prior systemic therapy for prostate cancer (except bisphosphonates or hormonal therapy)
• At least 6 weeks since prior investigational drugs or devices
• No other concurrent therapy for this disease
• No concurrent participation in another clinical trial
• No concurrent bisphosphonates unless initiated prior to study
• No concurrent immunosuppressive drugs
• No other concurrent experimental therapies