Radiolabelling antibody fragments

Arano Y, Fujioka Y, Akizawa H, et al. Chemical design of radiolabeled antibody fragments for low renal radioactivity levels. Cancer Res 1999 59 128-134. 

BEHR, T.M., GOLDENBERG, D.M., BECKER, W., Reducing the renal uptake of radiolabelled antibody fragments and peptides for diagnosis and therapy Present status, future prospects and limitations, Eur. J. Nucl. Med. 25 (1998) 201-212. 

Harwood SJ, Valdivia S, Hung GL, Quenzer RW (1999) Use of sulesomab, a radiolabeled antibody fragment, to detect osteomyelitis in diabetic patients with foot ulcers by leukoscintigraphy. Clin. Infect. Dis. 28(6) 1200-1205... 

The radioactivity excreted in the urine for 6 hours postinjection of HML-Fab was then analyzed to assess the present chemical design of radiolabeled antibody fragments. On size-exclusion HPLC, more than 85 % of the radioactivity was eluted at the low molecular weight fractions and about 12 % of the radioactivity was eluted in fractions similar to those of the intact Fab fragment. On reversed-phase HPLC of the urine sample, over 93 % of the low molecular weight fractions had a retention time identical to that of ffjeto-iodohippuric acid. These findings indicated that the low renal radioactivity levels of HML-Fab were attributed to rapid and selective release of /weto-iodohippuric acid in the kidney. 

Figure 13.5 Outline of the production strategy of CEA-SCAN. The antibody-producing hybridoma cell line was originally obtained by standard methods of hybridoma generation. Spleen-derived murine B-lymphocytes were fused with murine myeloma calls. The resulting stable hybridomas were screened for the production of anti-CEA monoclonals. The clone chosen produces an IgG anti-CEA antibody. Note that the finished product outlined above is not radiolabelled. The freeze-dried antibody preparation (which has a shelf life of 2 years at 2-8 °C) is reconstituted immediately prior to its medical use. The reconstituting solution contains 99mTc, and is formulated to facilitate direct conjugation of the radiolabel to the antibody fragment...

The possibility of using radiolabeled antibodies or antibody fragments to target cell surface antigens is very attractive, because this would enable the in vivo measurement of different cell types and phenotypes. Unfortunately, the development of these techniques is still in its infancy. A study of an antibody to NCA-90 surface antigen on granulocytes showed that clearance from the blood into inflamed areas appeared to be nonspecific (20). 

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