PRIOR CONCURRENT THERAPY: Recovered from toxicity of any prior therapy Biologic therapy: No prior autologous or allogeneic tumor vaccines No concurrent other immunotherapy Chemotherapy: At least 4 weeks since chemotherapy No concurrent chemotherapy Endocrine therapy: Flutamide discontinued and subsequent progression prior to entry 3 consecutive rising PSA values at least 2 weeks apart No concurrent corticosteroids (except for life-threatening conditions) Medical hormonal therapy to maintain castrate testosterone levels required in the absence of orchiectomy Radiotherapy: At least 4 weeks since radiotherapy No concurrent radiotherapy Surgery: Prior surgery allowed