Biokinetics of a radioiodinated antibreast carcinoma monoclonal antibody and fragment in humans
Monoclonal antibody B6.2 is promising for the detection of breast cancers; it binds to >80% of human breast carcinoma (hbc) lines, its antigen is not seen in serum, and it localizes selectively in hbc xenografts in nude mice. The authors have studied the biokinetics of I-131 activity following injection of I-131-IgG and F(ab')/sub 2/ each in 4 patients (pts). The antibody was labeled using iodogen and tested for specific binding to hbc membrane extracts prior to injection. Pts received 0.6-1.1 mCi of I-131 and 50-100 ..mu..g of protein. Blood clearance of I-131 activity was biphasic with half times of 2 and 15.4 hrs for IgG; 1 and 30 hrs for F(ab')/sub 2/. Dehalogenation was noted: by 72 hrs post-injection, 22% (IgG) and 21% (F(ab')/sub 2/) of the injected dose of I-131 was found in the urine. In 2 pts receiving I-131 IgG, stomach uptake was 7-10% at 24 hrs. Protein associated activity in the blood was >90% for the first 8 hrs and gradually decreased to 79% (IgG) and 58% (F(ab')/sub 2/) at 48 hrs. High liver uptake, reported with other antibody systems, was not observed; <20% of the activity was seen in the liver at all time points for both proteins. In 1/4 pts receiving IgG and 4/4 receiving F(ab')/sub 2/, bone marrow uptake was clearly noted. In these pts, >20% of the activity present in blood was cell associated. This is not inconsistent with the observation that B6.2 binds to granulocytes in vitro. Increased binding to cells in the blood for F(ab')/sub 2/ probably accounts for the anomolously longer blood clearance half times observed for F(ab')/sub 2/ vs IgG and low liver accumulation most likely reflects the absence of hepatic or circulating B6.2 antigen.
- Research Organization:
- Harvard Medical School, Boston, MA
- OSTI ID:
- 6593470
- Report Number(s):
- CONF-840619-; TRN: 87-018933
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CARCINOMAS
DIAGNOSIS
MAMMARY GLANDS
MONOCLONAL ANTIBODIES
LABELLING
RADIOPHARMACEUTICALS
CHEMICAL PREPARATION
RETENTION FUNCTIONS
TISSUE DISTRIBUTION
UPTAKE
BIOMEDICAL RADIOGRAPHY
BLOOD CHEMISTRY
BONE MARROW
PROTEINS
RADIONUCLIDE KINETICS
SCINTISCANNING
ANIMAL TISSUES
ANTIBODIES
BODY
COUNTING TECHNIQUES
DIAGNOSTIC TECHNIQUES
DISEASES
DISTRIBUTION
DRUGS
FUNCTIONS
GLANDS
HEMATOPOIETIC SYSTEM
LABELLED COMPOUNDS
MEDICINE
NEOPLASMS
NUCLEAR MEDICINE
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPE SCANNING
RADIOLOGY
SYNTHESIS
TISSUES
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550501 - Metabolism- Tracer Techniques