Radiolabeled chimeric anti-CEA monoclonal antibody compared with the original mouse monoclonal antibody for surgically treated colorectal carcinoma.

Biodistribution and tumor uptake of a chimeric human-mouse monoclonal antibody (MAb) and the original mouse MAb have been comparatively studied. METHODS: Eighteen patients with suspected colorectal cancer scheduled for surgery underwent immunoscintigraphy with 123I-labeled chimeric anti-CEA MAb. Iodine-125 and 131I trace-labeled chimeric and original mouse MAb were simultaneously injected for biodistribution studies. RESULTS: Similar serum kinetics and a low immunogenicity were observed for both antibodies. Mean binding capacity to CEA measured in PBS after radiolabeling was identical for both MAbs and it was slightly decreased when measured in serum 1-4 hr after injection. Radiochromatograms of patients sera showed immune complex formation related to the amount of circulating CEA. Postoperative ex vivo radioactivity counting in tissue samples revealed similar antibody distributions with notably similar antibody uptakes in tumors. High tumor uptakes (between 0.02 to 0.06% injected dose per g) were observed in 3 of 13 patients operated for primary or metastatic colorectal cancer. CONCLUSION: In this dual-label technique, the radioiodinated anti-CEA IgG4 chimeric MAb and the original mouse IgG1 MAb were shown to have very similar behavior in colorectal cancer patients.

Modernin arkeologian anti antiikintutkimukselle

Eeva-Maria Viitanen

Suomalaisen nuorisotutkimuksen anti yksissä kansissa

Hannu Välimäki

The inhibition of MAPK potentiates the anti-angiogenic efficacy of mTOR inhibitors.

The mammalian target of rapamycin (mTOR) which is part of two functionally distinct complexes, mTORC1 and mTORC2, plays an important role in vascular endothelial cells. Indeed, the inhibition of mTOR with an allosteric inhibitor such as rapamycin reduces the growth of endothelial cell in vitro and inhibits angiogenesis in vivo. Recent studies have shown that blocking mTOR results in the activation of other prosurvival signals such as Akt or MAPK which counteract the growth inhibitory properties of mTOR inhibitors. However, little is known about the interactions between mTOR and MAPK in endothelial cells and their relevance to angiogenesis. Here we found that blocking mTOR with ATP-competitive inhibitors of mTOR or with rapamycin induced the activation of the mitogen-activated protein kinase (MAPK) in endothelial cells. Downregulation of mTORC1 but not mTORC2 had similar effects showing that the inhibition of mTORC1 is responsible for the activation of MAPK. Treatment of endothelial cells with mTOR inhibitors in combination with MAPK inhibitors reduced endothelial cell survival, proliferation, migration and tube formation more significantly than either inhibition alone. Similarly, in a tumor xenograft model, the anti-angiogenic efficacy of mTOR inhibitors was enhanced by the pharmacological blockade of MAPK. Taken together these results show that blocking mTORC1 in endothelial cells activates MAPK and that a combined inhibition of MAPK and mTOR has additive anti-angiogenic effects. They also provide a rationale to target both mTOR and MAPK simultaneously in anti-angiogenic treatment.

Leishmania RNA virus: when the host pays the toll.

The presence of an RNA virus in a South American subgenus of the Leishmania parasite, L. (Viannia), was detected several decades ago but its role in leishmanial virulence and metastasis was only recently described. In Leishmania guyanensis, the nucleic acid of Leishmania RNA virus (LRV1) acts as a potent innate immunogen, eliciting a hyper-inflammatory immune response through toll-like receptor 3 (TLR3). The resultant inflammatory cascade has been shown to increase disease severity, parasite persistence, and perhaps even resistance to anti-leishmanial drugs. Curiously, LRVs were found mostly in clinical isolates prone to infectious metastasis in both their human source and experimental animal model, suggesting an association between the viral hyperpathogen and metastatic complications such as mucocutaneous leishmaniasis (MCL). MCL presents as chronic secondary lesions in the mucosa of the mouth and nose, debilitatingly inflamed and notoriously refractory to treatment. Immunologically, this outcome has many of the same hallmarks associated with the reaction to LRV: production of type 1 interferons, bias toward a chronic Th1 inflammatory state and an impaired ability of host cells to eliminate parasites through oxidative stress. More intriguing, is that the risk of developing MCL is found almost exclusively in infections of the L. (Viannia) subtype, further indication that leishmanial metastasis is caused, at least in part, by a parasitic component. LRV present in this subgenus may contribute to the destructive inflammation of metastatic disease either by acting in concert with other intrinsic "metastatic factors" or by independently preying on host TLR3 hypersensitivity. Because LRV amplifies parasite virulence, its presence may provide a unique target for diagnostic and clinical intervention of metastatic leishmaniasis. Taking examples from other members of the Totiviridae virus family, this paper reviews the benefits and costs of endosymbiosis, specifically for the maintenance of LRV infection in Leishmania parasites, which is often at the expense of its human host.

A qui administrer le vaccin anti-pneumococcique? [We should received and pneumococcal immunization?]

Alors que l'immunisation active contre l'influenza semble être actuellement largement entrée dans la pratique médicale, force est de constater que c'est loin d'être le cas pour les infections à pneumocoque. La vaccination anti-pneumocoque. La vaccination anti-pneumococcique, qui est incluse dans les schémas d'immunisation de nombreux pays, ne fait actuellement pas l'objet de recommendations particulières en Suisse et son utilisation y reste marginale. Compte tenu du nombre élevé d'infections sévères et de décès potentiellement évitables, sa généralisation à tous les groupes à risque doit être encouragée. De plus, cette stratégie pourrait se révéler utile face à la progression inexorable de la proportion de souches résistantes à la pénicilline et aux autres microbes.

Anti-idiotypic monoclonal antibody AB3, reacting with the primary antigen (CEA), can localize in human colon-carcinoma xenografts as efficiently as AB1.

BALB/c mice were immunized with anti-idiotypic monoclonal (MAb) antibody (anti-Id or Ab2) directed against an AB1 MAb anti-carcinoembryonic (CEA) in order to obtain AB3 MAbs (anti-anti-Id). AB3 MAbs were shown to recognise the primary antigen (CEA) and one of them was tested extensively in vitro and in vivo. This AB3 MAb was shown to bind specifically to CEA on frozen sections of a human colon carcinoma by immunoperoxidase. Scatchard plot analyses showed that the affinity of this AB3 was of the same order of magnitude as the AB1. In vivo experiments, in nude mice bearing CEA-producing human colon-carcinoma xenografts showed that up to 30% of the intravenously injected dose of 125I-labelled AB3 were localized per gram of tumour tissue. Furthermore, calculation of the ratios of AB3 concentration in the tumour over those in normal organs such as lung, liver, kidney, spleen and bone gave relatively high values similar to results obtained with AB1. All together our results show that AB3 can localize as efficiently and specifically in the tumour as AB1, despite the fact that the mice from which it was derived were immunized with a mouse MAb (AB2) and had never been exposed to CEA.

Parasitic diseases, with an emphasis on experimental cutaneous Leishmaniasis

Parasites have to survive in their vertebrate host during a sufficiently prolonged period of time to achieve their life cycle through successful transmission via insect vectors. In their vertebrate hosts, parasites are often confronted by vigorous effector immune responses that they have to subvert somehow to be able to outlast and be successfully transmitted.

The anti-lymphoma activity of APO866, an inhibitor of nicotinamide adenine dinucleotide biosynthesis, is potentialized when used in combination with anti-CD20 antibody.

Abstract APO866 is an inhibitor of nicotinamide adenine dinucleotide (NAD) biosynthesis that exhibits potent anti-lymphoma activity. Rituximab (RTX), an anti-CD20 antibody, kills lymphoma cells by direct apoptosis and antibody- and complement-dependent cell-mediated cytotoxicities, and has clinical efficacy in non-Hodgkin cell lymphomas. In the present study, we evaluated whether RTX could potentiate APO866-induced human B-lymphoma cell death and shed light on death-mediated mechanisms associated with this drug combination. We found that RTX significantly increases APO866-induced death in lymphoma cells from patients and lines. Mechanisms include enhancement of autophagy-mediated cell death, activation of caspase 3 and exacerbation of mitochondrial depolarization, but not increase of reactive oxygen species (ROS) production, when compared with those induced by each drug alone. In vivo, combined administration of APO866 with RTX in a laboratory model of human aggressive lymphoma significantly decreased tumor burden and prolonged survival over single-agent treatment. Our study demonstrates that the combination of RTX and APO866 optimizes B-cell lymphoma apoptosis and therapeutic efficacy over both compounds administered separately.

Parasitic nematodes of Apodemus alpicola (Mammalia : Rodentia : Muridae) collected in Switzerland

An analysis was made of the parasitic nematode fauna of the gastrointestinal tract of Apodemus alpicola collected in Switzerland. Three nematode species, viz., Heligmosomoides polygyrus, Syphacia stroma and Eucoleus gastricus were obtained. Although the parasitic nematode fauna of 10 species of the genus Apodemus in the Eurasian Continent including Switzerland, Taiwan and Japanese Islands have been reported, this is the first record from A. alpicola.