Sibylle Pochon

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Human CD21 has been described as a receptor for the C3d,g and iC3b proteins of complement, for the Epstein-Barr virus, and also for IFN-alpha. We reported recently that CD23, a low affinity receptor for IgE (Fc epsilon R2), is a new functional ligand for CD21. To determine the site of interaction of CD23 on CD21, we analyzed the ability of purified(More)
The molecule CD23, a low-affinity receptor for IgE (Fc epsilon R2), is a type II transmembrane molecule expressed on many haemopoietic cell types. CD23 has pleiotropic roles in the control of lymphocyte behaviour, suggesting that CD23 may interact with another ligand in addition to IgE. To identify such a CD23 ligand, we expressed and purified full-length(More)
OBJECTIVES To evaluate BR55, a new VEGFR2-specific ultrasound contrast agent, for imaging prostate tumors in an orthotopic model in the rat. MATERIALS AND METHODS Rat prostate adenocarcinoma were established by injection of G Dunning R-3327 tumor cells in one lobe of the prostate of Copenhagen rats. Imaging experiments were performed with BR55, SonoVue,(More)
Tuftsin, Thr-Lys-Pro-Arg (TKPR), is an immunostimulatory peptide with reported nervous system effects as well. We unexpectedly found that tuftsin and a higher affinity antagonist, TKPPR, bind selectively to neuropilin-1 and block vascular endothelial growth factor (VEGF) binding to that receptor. Dimeric and tetrameric forms of TKPPR had greatly increased(More)
OBJECTIVES Ultrasound molecular imaging is increasingly used in preclinical studies to measure the expression of vascular markers during inflammation process. In this context, a new ultrasound contrast agent functionalized with a recombinant P-selectin glycoprotein ligand-1 analogue (rPSGL-Ig) was developed (MBrPSGL-Ig). This agent was assayed in vitro and(More)
OBJECTIVES BR55, an ultrasound contrast agent functionalized with a heterodimer peptide targeting the vascular endothelial growth factor receptor 2 (VEGFR2), was evaluated in vitro and in vivo, demonstrating its potential for specific tumor detection. MATERIALS AND METHODS The targeted contrast agent was prepared by incorporation of a biospecific(More)
To characterise clinically translatable long-circulating (BR38) and VEGFR2-targeted (BR55) microbubbles (MB) and to assess their ability to discriminate breast cancer models with different aggressiveness. The circulation characteristics of BR38 and BR55 were investigated in healthy mice. The relative blood volume (rBV) of MDA-MB-231 (n = 5) or MCF-7 (n = 6)(More)
BACKGROUND AND PURPOSE Molecular imaging of therapeutic interventions with targeted agents that simultaneously carry drugs or genes for local delivery is appealing. We investigated the ability of a novel microbubble carrier (immunobubble) for abciximab, a glycoprotein IIb/IIIa receptor inhibitor, for ultrasonographic molecular imaging of human clots. (More)
Human CD21 has previously been described as a receptor for the C3d,g and iC3b proteins of complement, as a receptor for the gp350/220 envelope glycoprotein of the Epstein-Barr virus (EBV) and also as a receptor for inerferon-alpha (IFN-alpha). Structurally, CD21 consists of 15 to 16 short consensus repeats (SCR) of 60 to 75 amino acids followed by a(More)
Tumour xenografts of well-discernible sizes can be examined well by molecular ultrasound. Here, we investigated whether very early breast carcinomas express sufficient levels of VEGFR2 for reliable molecular ultrasound imaging with targeted microbubbles. MCF-7 breast cancer xenografts were orthotopically implanted in nude mice (n = 26). Tumours measuring(More)