title: Preparation of cystamine core dendrimer and antibody-dendrimer conjugates for MRI angiography.
abstract: Herein we report the preparation along with the in vivo and in vitro MRI characterization of two generation four and five cystamine core dendrimers loaded with thirty and fifty-eight derivatized Gd-DOTA (G4SS30, G5SS58) respectively. Likewise the development and characterization of two half-dendrimers conjugated to the F(ab')(2) fragment of the monoclonal antibody (mAb) panitumumab functionalized with a maleimide conjugation functional group site (Ab-(G4S15)(4), Ab-(G5S29)(4)) are also described. The in vitro molar relaxivity of the Ab-(G4S15)(4) conjugate, measured at pH 7.4, 22 °C, and 3T showed a moderate increase in relaxivity as compared to Magnevist (6.7 vs 4.0 mM(-1) s(-1)) while the Ab-(G5S29)(4) conjugate was 2-fold higher (9.1 vs 4.0 mM(-1) s(-1)). The data showed that only a high injection dose (0.050 mmol Gd(3+)/kg) produced a detectable contrast enhanced contrast for the Ab-(G4S15)(4) conjugate while a lower dose (0.035 mmol Gd(3+)/kg) was sufficient for the Ab-(G5S29)(4) conjugate. The antibody-SMCC conjugate was purified by a Sephadex G-100 column, and the antibody-dendrimer-based agents were purified by spin filtration using a Centricon filter (50,000 MCO). The protein assay coupled with cysteine and Ellman's assay indicated an antibody to dendrimer ratio of 1:4. The in vivo blood clearance half-lives of the four agents measured at the jugular vein were ~12-22 min.
authors: Radioimmune & Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, 10 Center Drive, Bethesda, Maryland 20892, United States.
authors: Kido
authors: K
authors: Nwe
authors: Diane E
authors: DE
authors: Milenic
authors: Geoffrey L
authors: GL
authors: Ray
authors: Young-Seung
authors: YS
authors: Kim
authors: Martin W
authors: MW
authors: Brechbiel
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D003287:Contrast Media / Q000737:chemistry; D003538:Cystamine / Q000737:chemistry*; D050091:Dendrimers / Q000737:chemistry*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D051379:Mice
chemical_list: D000911:Antibodies, Monoclonal; D003287:Contrast Media; D050091:Dendrimers; D003538:Cystamine