EVALUATION OF A NEW DTPA-DERIVATIVE CHELATOR - COMPARATIVE BIODISTRIBUTION AND IMAGING STUDIES OF IN-111 LABELED B3 MONOCLONAL-ANTIBODY IN ATHYMIC MICE BEARING HUMAN EPIDERMOID CARCINOMA XENOGRAFTS
L. Camera et al., EVALUATION OF A NEW DTPA-DERIVATIVE CHELATOR - COMPARATIVE BIODISTRIBUTION AND IMAGING STUDIES OF IN-111 LABELED B3 MONOCLONAL-ANTIBODY IN ATHYMIC MICE BEARING HUMAN EPIDERMOID CARCINOMA XENOGRAFTS, Nuclear medicine and biology, 20(8), 1993, pp. 955-962
Biodistribution and imaging characteristics of monoclonal antibody (MA
b) B3 conjugated to either the 2-(p-isothiocyanatobenzyl)-cyclohexyl-D
TPA (CHX-B) or 2-(p-isothiocyanatobenzyl)-6-methyl-DTPA (1B4M) and lab
eled with In-111, were evaluated in nude mice bearing A431 human epide
rmoid carcinoma xenografts. MAb B3, is a murine IgG1k reacting with a
carbohydrate antigen abundantly expressed by most carcinomas. Both In-
111-(CHX-B)-B3 and In-111-(1B4M)-B3 showed good tumor targeting with p
eak values observed at 72 h with 27.6 +/- 7.6 and 25.4 +/- 1.7% ID/g,
respectively (P > 0.05). High tumor-to-organ ratios were also observed
and, confirmed by the imaging results. In particular, tumor-to-liver
ratios increased from 5.0 +/- 0.9 at 24 h to 9.2 +/- 2.0 at 168 h for
In-111-(CHX-B)-B3 and from 4.5 +/- 0.6 to 8.9 +/- 3.5 for In-111-(1B4M
)-B3. This was mainly the result of low liver accumulation of both In-
111-(CHX-B)-B3 and In-111-(1B4M)-B3, with only 2.48 +/- 0.46 and 2.5 /- 0.9% ID/g at 168 h, respectively (P > 0.05). Our findings indicate
that either CHX-B or 1B4M can be successfully used for In-111-labeling
of MAbs and that In-111-B3 may represent a promising radioimmunoimagi
ng agent.