Anti-Angiogenesis Therapy of Cancer Cells using 153Sm-Bevasesomab

Purpose: Angiogenesis is essential for tumor growth or metastasis. Avastin is a monoclonal antibody that is used in treating angiogenesis. We labelled this monoclonal antibody with samarium153 and performed in vitro quality control tests as a first step in the production of a new radiopharmaceutical.Material and Methods: For a successful radiolabeling, we chose DOTA-NHS as the bifunctional chelating agent and optimized radiolabeling condition with modifications of the factors such as reaction time and molar ratio which are known to be very critical in radiolabeling. The efficiency and in vitro stability of antibody labelling were determined using thin layer chromatography. The integrity of the radiolabeled antibody was checked by SDS-PAGE. Biodistribution study of 153Sm-DOTA –avastin was carried out in BALB/c mice at 2, 24, 48 and 72 hours after injection. Immunoreactivity and toxicity of the complex were tested on colon cancer cell line by MTT.Results: The efficiency of antibody labelling was more than 99%. The in vitro stability of the labelled product in human serum after 120h was 78 ±2%. There was no fragmentation in the labelled antibody during SDS-PAGE protocol. The highest of %ID/g was observed in the blood, liver, lungs and spleen. The immunoreactivity of the complex was 89±1.4%. At a concentration of 1 nM, the complex killed 70±3% of SW480 cells. At 1.9 nM, 90±5% of the cells were killed.Discussion: The monoclonal antibody avastin against angiogenesis was effectively radiolabeled with 153Sm. The results showed that the new complex could be considered a promising tracer for noninvasive delineation of angiogenesis.

Label-free phenotyping of peripheral blood lymphocytes by infrared imaging

FTIR imaging enables to effectively discriminate lymphocyte subpopulations without antibody labelling.

Detection of Intrastrain Antigenic Variation of Bacteroides fragilis Surface Polysaccharides by Monoclonal Antibody Labelling

ABSTRACT Bacteroides fragilis is a constituent of the normal resident microbiota of the human intestine and is the gram-negative obligately anaerobic bacterium most frequently isolated from clinical infection. Surface polysaccharides are implicated as potential virulence determinants. We present evidence of within strain immunochemical variation of surface polysaccharides in populations that are noncapsulate by light microscopy as determined by monoclonal antibody labelling. Expression of individual epitopes can be enriched from a population of an individual strain by use of immunomagnetic beads. Also, individual colonies in which either >94% or <7% of the bacteria carry an individual epitope retain this level of expression when subcultured into broth. In broth cultures where >94% of the bacteria carry a given epitope, there is no enrichment for other epitopes recognized by different polysaccharide-specific monoclonal antibodies. This intrastrain variation has important implications for the development of potential vaccines or immunodiagnostic tests.

The sacral neural crest contributes neurons and glia to the post-umbilical gut: spatiotemporal analysis of the development of the enteric nervous system

The majority of the enteric nervous system is derived from vagal neural crest cells (NCC), which migrate to the developing gut, proliferate, form plexuses and differentiate into neurons and glia. However, for some time, controversy has existed as to whether cells from the sacral region of the neural crest also contribute to the enteric nervous system. The aim of this study was to investigate the spatiotemporal migration of vagal and sacral NCC within the developing gut and to determine whether the sacral neural crest contributes neurons and glia to the ENS. We utilised quail-chick chimeric grafting in conjunction with antibody labelling to identify graft-derived cells, neurons and glia. We found that vagal NCC migrated ventrally within the embryo and accumulated in the caudal branchial arches before entering the pharyngeal region and colonising the entire length of the gut in a proximodistal direction. During migration, vagal crest cells followed different pathways depending on the region of the gut being colonised. In the pre-umbilical intestine, NCC were evenly distributed throughout the splanchnopleural mesenchyme while, in the post-umbilical intestine, they occurred adjacent to the serosal epithelium. Behind this migration front, NCC became organised into the presumptive Auerbach's and Meissner's plexuses situated on either side of the developing circular muscle layer. The colorectum was found to be colonised in a complex manner. Vagal NCC initially migrated within the submucosa, internal to the circular muscle layer, before migrating outwards, adjacent to blood vessels, towards the myenteric plexus region. In contrast, sacral NCC, which also formed the entire nerve of Remak, were primarily located in the presumptive myenteric plexus region and subsequently migrated inwards towards the submucosal ganglia. Although present throughout the post-umbilical gut, sacral NCC were most numerous in the distal colorectum where they constituted up to 17% of enteric neurons, as identified by double antibody labelling using the quail-cell-specific marker, QCPN and the neuron-specific marker, ANNA-1. Sacral NCC were also immunopositive for the glial-specific antibody, GFAP, thus demonstrating that this region of the neural crest contributes neurons and glia to the enteric nervous system.