Phase II Trial of Monoclonal Antibody (J591) in Combination With Low-Dose Subcutaneous Interleukin-2

Eligibility Criteria: * Histologic diagnosis (recent or remote) of prostate adenocarcinoma * Metastatic or recurrent carcinoma of the prostate defined by abnormal CT or MRI and/or abnormal bone scan and/or rising PSA. * Rising PSA on 3 serial determinations over a period of \> or equal to 2 weeks. * PSA \> or equal to 1.0 at the time of entry. * If patient is being treated with an LHRH analog the drug: a. must be maintained for the duration of the study or b. must be terminated \> or equal to 10 weeks prior to entry (for 28 day depot preparations) or 24 weeks (for 3 month depot preparations). Exclusion Criteria: * Prior cytotoxic chemotherapy and/or radiation therapy within 4 weeks of entry. * History of CNS metastasis, and/or history of seizure and/or stroke. * Lab values: ANC\<1500/mm3; platelet count\<100,000/mm3; serum creatinine\>2.0; SGOT\>2 x normal; bilirubin (total)\>1.5; serum calcium\> or equal to 11.5. * Active serious infection not controlled by antibiotics. * Active angina pectoris or NYHA Class III-IV. * Karnofsky Performance Status \<60. * Life Expectancy \< 3 months. * Age\< 21y. * Other serious illness(es) involving the cardiac, respiratory, CNS, renal, hepatic or hematological organ systems which might preclude completion of this study or interfere with determination of causality of any adverse effects experienced in this study. * Untreated thyroid disease, with the exception of treated and stable hyperthyroidism or hypothyroidism for at least 4 weeks prior to entry.