Radiolabelled monoclonal antibodies have been used in the diagnosis of certain types of cancer. They have also been applied experimentally in the treatment of tumours. The major drawback of the method, however, is the high background activity due to the presence of label in the circulation and non-specific uptake by normal tissue. Several strategies have been proposed to overcome this problem, including computed background subtraction, use of a second antibody and local delivery. Antibodies show a slow accumulation in tumour tissue. By separating the time of administration of the antibody from that of the label, one can improve tumour detection, as the radioisotope may be injected when the tumour-bound/non-tumour-bound ratio has reached a maximum. The label should display a rapid clearance and be readily captured by the antibody already targeted onto the tumour cells. One of these strategies of tumour - pretargeting is based on the avidin - biotin system, a system which has already been used extensively in immunohistochemistry and ELISA. We describe a two-step pretargeting protocol in ovarian cancer and a three-step approach in CEA - secreting tumours based on the avidin - biotin system.
|Number of pages||8|
|Journal||Regional Cancer Treatment|
|Publication status||Published - 1995|
- Monoclonal antibodies
ASJC Scopus subject areas