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Preparation, Phototoxicity and Biodistribution Studies of Anti‐Carcinoembryonic Antigen Monoclonal Antibody‐Phthalocyanine Conjugates
Author(s) -
Carcenac Magali,
Larroque Christian,
Langlois Rejean,
Lier Johan E.,
Artus JeanClaude,
Pelegrin Andre
Publication year - 1999
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1999.tb08304.x
Subject(s) - conjugate , monoclonal antibody , biodistribution , chemistry , carcinoembryonic antigen , microbiology and biotechnology , in vivo , phototoxicity , concanavalin a , antigen , in vitro , antibody , radioimmunotherapy , biochemistry , biology , cancer , immunology , mathematical analysis , genetics , mathematics
Immunophototherapy of cancer combines the specificity of a monoclonal antibody (MAb) to an overexpressed tumor marker with the phototoxic properties of a conjugated dye. Aluminum tetrasulfophthalocyanine (AlPcS 4 ) was covalently coupled to a 35A7 MAb directed against carcinoembryonic antigen (CEA) via a five‐carbon spacer chain (A 1 ) to yield conjugates with a molar ratio ranging from 5 to 16 mol of AlPcS 4 per mol of 35A7 MAb. Conjugates were labeled with radioiodine for characterization. The immunoreactivity of the conjugates, determined in a direct binding assay on CEA coupled to sepharose, was not modified by the coupled AlPcS 4 A 1 molecules. In vivo , these conjugates were evaluated in nude mice bearing human colon carcinoma xenografts (T380). 35A7 MAb‐(AlPcS 4 A 1 ) s , 35A7 MAb‐(AlPcS 4 A 1 ,) 12 and 35A7 MAb‐(AIPcS 4 A,) 16 conjugates displayed a tumor uptake of 35 ± 5.0%, 40 ± 5.7% and 32 ± 3.3% of the injected dose per gram of tumor tissue, respectively, corresponding to an uptake of 97%, 104% and 91% as compared to that of the unconjugated 35A7 MAb. In each experimental group, the tumor‐to‐normal tissue ratios obtained with the conjugates were almost identical to those obtained with unconjugated 35A7 MAb. Average values of 1.8, 7 and about 30 were obtained for blood, liver and muscle, respectively. Phototoxic efficacy of the 35A7 MAb‐(AlPcS 4 A,) 12 conjugate was demonstrated in vitro on the LoYo cell line giving a 91 % growth inhibition for a 2.50 μ/mL AlPcS4A 1 concentration. We conclude that these conjugates demonstrate clear in vivo tumor‐seeking capacity and in vitro photocytotoxic properties. Such conjugates could thus be promising candidate drugs for clinical photodynamic therapy of cancers expressing CEA.