title: In vitro studies of gadolinium-DTPA conjugated with monoclonal antibodies as cancer-specific magnetic resonance imaging contrast agents.
abstract: The monoclonal antibodies, 9.2.27 against human melanoma cell lines and WM53 against leukemia cell lines, were conjugated with cyclic anhydride gadolinium-diethylenetriaminepenta-acetic acid (Gd-cDTPAa) and used as tumor-specific contrast agents in magnetic resonance imaging (MRI). The data indicate that Gd-DTPA-9.2.27 in solution decreased the T1 relaxation of water protons at 7.0 Tesla (300 MHz) in direct proportion to the gadolinium concentration, and this effect was greater than in Gd-DTPA solutions. These conjugates show high specificity for melanoma and leukemia cell lines. T1 relaxation time at 7.0 Tesla, measured for the melanoma cell line (MM-138) and leukemia cell line (HL-60) after incubation at 37 degrees C for 4 hr, were significantly decreased (approximately 25%) relative to controls. The gadolinium concentration in cells and washing solutions was measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A linear relationship was observed between T1 relaxation rates and gadolinium concentrations obtained by ICP-AES. The ICP-AES results showed no gadolinium uptake in the non-targeted HT-29 colorectal cancer cells.
authors.affiliation: Center for Experimental Radiation Oncology, Shahrekord University of Medical Sciences, Iran.
authors.forename: D
authors.initials: D
authors.lastname: Shahbazi-Gahrouei
authors.forename: S M
authors.initials: SM
authors.lastname: Rizvi
authors.forename: M A
authors.initials: MA
authors.lastname: Williams
authors.forename: B J
authors.initials: BJ
authors.lastname: Allen
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000493:pharmacokinetics*; D003287:Contrast Media / Q000493:pharmacokinetics*; D019786:Gadolinium DTPA / Q000737:chemistry / Q000493:pharmacokinetics*; D018922:HL-60 Cells / Q000378:metabolism; D019073:HT29 Cells / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008545:Melanoma / Q000378:metabolism; D051379:Mice; D019275:Radiopharmaceuticals / Q000737:chemistry / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D003287:Contrast Media; D019275:Radiopharmaceuticals; D019786:Gadolinium DTPA