Labelling of monoclonal antibody IOR-CEA1, with 131I for the method of chloramine T, for the early diagnosis of carcinoembryonic antigen. Preliminary report

The monoclonal antibody (AcMo) IOR-CEA1 is considered a tumor marker for principally colon and rectal cancer. With the aid of nuclear techniques the molecule was labeled with radioisotope 131I, produced at IPEN Radioisotope Production Plant. Initially, the monoclonal antibody was labeled with 131I according to Chloramine T techniques, as described in the 'Guide of Radioidonation of Amersham Life Science'. A satisfactory result was not obtained, as the antibody could not be bounded to 131I thus, modifications were made to the technique, increasing incubation time and concentration of the oxidant agent (Chloramine T). As a result, in the radiochemical purity (PQR) a percentage average of the 97,57% ± 1,53. Stability of the labeled molecule was also asses, resulting in a molecule of PQR > 90%. This value was maintained even on the sixth day after being labeled. (author)