Purification and Characterization of a cAMP-Binding Protein of Volvox carteri f. nagariensis Iyengar

Feldwisch, Ortrun; Lammertz, Marion; Hartmann, E.; Palme, Klaus; Jastorff, Bernd; Jaenicke, Lothar

doi:10.1111/j.1432-1033.1995.tb20287.x

Cited by 1 publication

(1 citation statement)

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“…Besides pharmacokinetics and biodistribution discussed in the present report, multiple administrations may require a low immunogenic response to the tracer. Preliminary data suggest that the Affibody molecules display a low immunogenic potential, possibly due to rapid clearance from the body .…”

Section: Discussionmentioning

confidence: 99%

Evaluation of a Maleimido Derivative of CHX-A′′ DTPA for Site-Specific Labeling of Affibody Molecules

Tolmachev

Wållberg

et al. 2008

Bioconjugate Chem.

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Affibody molecules are a new class of small targeting proteins based on a common threehelix bundle structure. Affibody molecules binding a desired target may be selected using phage-display technology. An Affibody molecule ZHER2:342 binding with subnanomolar affinity to the tumor antigen HER2 has recently been developed for radionuclide imaging in vivo. Introduction of a single cysteine into the cysteine-free Affibody scaffold provides a unique thiol group for site-specific labeling of recombinant Affibody molecules. The recently developed maleimido-CHX-A” DTPA was site-specifically conjugated at the C-terminal cysteine of ZHER2:2395-C, a variant of ZHER2:342, providing a homogenous conjugate with a dissociation constant of 56 pM. The yield of labeling with 111In was > 99% after 10 min at room temperature. In vitro cell tests demonstrated specific binding of 111In-CHX-A” DTPAZ2395-C to HER2-expressing cell-line SKOV-3 and good cellular retention of radioactivity. In normal mice, the conjugate demonstrated rapid clearance from all non-specific organs except kidney. In mice bearing SKOV-3 xenografts, the tumor uptake of 111In-CHX-A” DTPAZ2395-C was 17.3 ± 4.8 % IA/g and the tumor-to-blood ratio 86 ± 46 (4 h post-injection). HER2-exprssing xenografts were clearly visualized 1 h post-injection. In conclusion, coupling of maleimido-CHX-A” DTPA to cysteine-containing Affibody molecules provides welldefined uniform conjugate, which can be rapidly labeled at room temperature and provides high-contrast imaging of molecular targets in vivo.

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Section: Discussionmentioning

confidence: 99%