In vitro studies have documented ␤2 glycoprotein I (␤2GPI) binding to endothelial cells (ECs) and trophoblast using antiphospholipid antibodies. The in vivo binding of ␤2GPI to these cells and the conditions that favor their interaction have not been investigated. We analyzed the in vivo distribution of cyanine 5.5-labeled ␤2GPI in mice and evaluated the effect of pregnancy and circulating antibodies on its tissue localization. The signal was detected in the liver by whole body scan and ex vivo analysis. The ␤2GPI failed to bind to the vascular endothelium and reacted only with the ECs of uterine vessels. In pregnant mice the protein was localized on ECs and trophoblast at the embryo implantation sites. Immunized mice showed a similar ␤2GPI biodistribution to naive mice but the immunized pregnant animals exhibited a significant increase in fetal loss associated with C3 and C9 deposition at the implantation sites. Treatment of mice with LPS after ␤2GPI-Cy5.5 injection promoted protein localization on gut and brain ECs associated with IgG, C1q, and C9 deposition in immunized mice. These findings indicate that ␤2GPI binding to EC requires priming with pro-inflammatory factors which is not needed for uterine and placental localization probably dependent on hormonal changes. (Blood. 2011;118(15): 4231-4238) IntroductionAntiphospholipid syndrome (APS) is characterized by vascular thrombosis and adverse pregnancy outcome associated with circulating antiphospholipid antibodies (aPL) which are believed to play an important pathogenic role in the development of the clinical manifestations of the syndrome. 1,2 Human ␤2-glycoprotein I (␤2GPI) has been recognized as the major antigenic target for antiphospholipid antibodies and in vivo models have shown that antibodies directed against this molecule are able to mediate thrombus formation. 3,4 Beta2GPI is a heavily glycosylated glycoprotein that circulates in blood at a concentration of 150-300 g/mL 5 and is synthesized mainly in the liver, although expression of ␤2GPI mRNA has also been detected in endothelial cells (ECs), central nervous system, astrocytes, and placenta. The physiologic function of this protein is still unclear, but the apparently healthy life of humans and mice deficient in ␤2GPI suggests that its role is not all that critical. [6][7][8][9] Most of the information now available on ␤2GPI has been collected following the observation that this protein is the main target of antiphospholipid (aPL) antibodies. 10,11 Patients with circulating antibodies to ␤2GPI are at increased risk of venous and arterial thrombosis as well as of pregnancy complications including miscarriage, preeclampsia and retarded fetal growth. 1,12 For this reason antibodies with this specificity have been included among the criteria for the diagnosis of aPL syndrome (APS). 13,14 The induction of fetal loss and promotion of thrombosis in animal models as a result of immunization with ␤2GPI or passive transfer of antibodies further support the pathogenic role of these antibodies. [15][16][17...

The efficacy of antibody-based immunotherapy is due to the activation of apoptosis, the engagement of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity (CDC). We developed a novel strategy to enhance CDC using bispecific antibodies (bsAbs) that neutralize the C-regulators CD55 and CD59 to enhance C-mediated functions. Two bsAbs (MB20/55 and MB20/59) were designed to recognize CD20 on one side. The other side neutralizes CD55 or CD59. Analysis of CDC revealed that bsAbs could kill 4-25 times more cells than anti-CD20 recombinant antibody in cell lines or cells isolated from patients with chronic lymphocytic leukemia. The pharmacokinetics of the bsAbs was evaluated in a human-SCID model of Burkitt lymphoma. The distribution profile of bsAbs mimics the data obtained by studying the pharmacokinetics of anti-CD20 antibodies, showing a peak in the tumor mass 3-4 days after injection. The treatment with bsAbs completely prevented the development of human/SCID lymphoma. The tumor growth was blocked by the activation of the C cascade and by the recruitment of macrophages, polymorphonuclear and natural killer cells. This strategy can easily be applied to the other anti-tumor C-fixing antibodies currently used in the clinic or tested in preclinical studies using the same vector with the appropriate modifications.

BackgroundBac7 is a proline-rich peptide with a potent in vitro antimicrobial activity against Gram-negative bacteria. Here we investigated its activity in biological fluids and in vivo using a mouse model of S. typhimurium infection.ResultsThe efficacy of the active 1-35 fragment of Bac7 was assayed in serum and plasma, and its stability in biological fluids analyzed by Western blot and mass spectrometry. The ability of the peptide to protect mice against Salmonella was assayed in a typhoid fever model of infection by determination of survival rates and bacterial load in liver and spleen of infected animals. In addition, the peptide's biodistribution was evaluated by using time-domain optical imaging. Bac7(1-35) retained a substantial in vivo activity showing a very low toxicity. The peptide increased significantly the number of survivors and the mean survival times of treated mice reducing the bacterial load in their organs despite its rapid clearance.ConclusionsOur results provide a first indication for a potential development of Bac7-based drugs in the treatment of salmonellosis and, eventually, other Gram-negative infections. The in vivo activity for this peptide might be substantially enhanced by decreasing its excretion rate or modifying the treatment schedule.

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In this work, iron/silica/gold core-shell nanoparticles (Fe 3 O 4 @SiO 2 @Au NPs) characterized by magnetic and optical properties have been synthetized to obtain a promising theranostic platform. In order to improve their biocompatibility, the obtained multilayer nanoparticles have been entrapped in polymeric micelles (PMs), decorated with folic acid moieties and tested in vivo for Photoacustic (PA) and MRI detection of ovarian cancer.