OBJECTIVES: I. Determine if immunization with glycosylated MUC-2 antigen with keyhole limpet hemocyanin (KLH) conjugate plus immunological adjuvant QS21 induces an antibody, helper T cell, and/or cytotoxic T cell response against glycosylated MUC-2 in patients with progressive prostate cancer. II. Determine the safety of this treatment regimen in this patient population. III. Determine the effect of glycosylated MUC-2 antigen with KLH conjugate on the T cell response against MUC-2 and by skin testing in these patients. IV. Assess the post immunization changes in prostate specific antigen levels and other objective parameters of disease including radionuclide bone scan and/or measurable disease in these patients.