DISEASE CHARACTERISTICS:

• Histologically confirmed metastatic adenocarcinoma of the colon or rectum

  • Not amenable to surgical resection
  • Recurrent or persistent disease after standard surgery, radiotherapy, and chemotherapy, including fluorouracil and irinotecan
• TAG-72 positive

PATIENT CHARACTERISTICS:

Age:

• 19 and over

Performance status:

• ECOG 0-2

Life expectancy:

• Not specified

Hematopoietic:

• WBC greater than 3,500/mm^3
• Platelet count greater than 125,000/mm^3
• Hemoglobin greater than 10 g/dL
• No nucleated RBC or significant teardrop RBC morphology

Hepatic:

• Bilirubin less than 1.5 mg/dL
• SGOT/SGPT less than 4 times normal
• Hepatitis B surface antigen negative

Renal:

• Creatinine less than 2.0 mg/dL

Other:

• HIV negative
• No other malignancy within the past 5 years except basal cell skin cancer
• No allergy to iodine
• No detectable antibody to monoclonal antibody CC49
• Not pregnant or nursing
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 3 weeks since prior immunotherapy and recovered
• No prior bone marrow or stem cell transplantation
• No other concurrent immunotherapy

Chemotherapy:

• See Disease Characteristics
• At least 3 weeks since prior chemotherapy and recovered
• No concurrent chemotherapy

Endocrine therapy:

• Not specified

Radiotherapy:

• See Disease Characteristics
• At least 3 weeks since prior radiotherapy and recovered
• No prior radiotherapy to more than 25% of red marrow
• No concurrent radiotherapy

Surgery:

• See Disease Characteristics
• At least 3 weeks since prior surgery and recovered