Comparison of tumor targeting of mouse monoclonal and goat polyclonal antibodies to carcinoembryonic antigen in the GW-39 human tumor-hamster host model.
We have evaluated 4 radioiodinated mouse monoclonal anticarcinoembryonic antigen antibodies (MAbs) by using the GW-39 human colorectal tumor xenograft transplanted i.m. in immunocompetent hamsters to determine whether there were any differences in their tumor localization properties. Additional comparisons were made to affinity-purified goat anticarcinoembryonic antigen antibody. Statistically significant differences were found in the percentage/g of tumor uptake and tumor/nontumor ratios among the antibodies, so that the antibodies could be ranked according to their tumor localization properties (NP-2 greater than NP-4 = goat antibody greater than NP-1 greater than NP-3). Although statistical differences were found, tumor/nontumor values generally were not distinguished by a factor of more than 1.5, suggesting that these differences may not be biologically significant. F(ab')2 fragments of NP-2 were found to be superior to NP-4 F(ab')2 fragments, giving tumor/liver and tumor/blood ratios of 16 and 11.5, respectively, within 3 days, in comparison to 5.4 and 3.8 for NP-4 F(ab')2 fragments. Mixtures of all of the MAbs or a mixture of NP-2 and NP-4 did not improve tumor localization, in comparison to NP-2 alone. These studies suggest that mixtures of these anticarcinoembryonic antigen MAbs may not afford better tumor imaging than the use of a certain single antitumor MAb.
Sharkey
R M
RM
Center for Molecular Medicine and Immunology, University of Medicine and Dentistry of New Jersey, Newark.
Primus
F J
FJ
Shochat
D
D
Goldenberg
D M
DM
D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging; D006224:Cricetinae; D006801:Humans; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D013997:Time Factors; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen