Giovanna Viale

Discrete regions of HIV-1 gp41 defined by syncytia-inhibiting affinity-purified human antibodies.

ObjectiveFine mapping of HIV-1 gp41 fusion-critical sites. Design and methodsAntibodies from human HIV-1-positive sera were affinity-purified on a panel of synthetic overlapping peptides spanning residues 526–682 of the extracellular portion of HIV-1 gp41. The syncytium-inhibiting capacity of the immunopurified antibodies and their differential reactivity on the synthetic peptides were tested. ResultsThis approach enabled the identification of residues 583–591 (ARILAVERY), 595–599 (QQLLG), 603–609 (CSGKLIC) and 664–673 (ELLELDKWAS) as possibly involved in the fusion process. Reduction in the anti-ARILAVERY, anti-CSGKLIC and anti-ELLELDKWAS antibody titres and frequencies correlates with disease progression. Syncytia-inhibition capacity of sera did not correlate with the presence of high-titre antibodies reacting with any of the peptides tested, suggesting that most fusion-affecting antibodies are not directed towards gp41. ConclusionsThis strategy may be relevant for understanding the contribution of anti-gp41 antibodies in protecting against the pathogenic effects of the virus and in the design of an effective env vaccine.

Preparation and characterization of anti-human chromogranin A and chromogranin B (secretogranin I) monoclonal antibodies

Chromogranin A, chromogranin B/secretogranin I and chromogranin C/secretogranin II are acidic sulphated and phosphorylated secretory proteins present in a large number of endocrine and neuronal tissues. It has been suggested that these proteins may be useful immunohistochemical markers for human tumours of endocrine origin and their measurement in plasma has been proposed as a diagnostic tool in patients with these tumours. In order to obtain anti-human chromogranins/secretogranins antibodies for clinical applications, we immunized mice with whole chromaffin granules isolated from human pheochromocytoma. The immune sera analysed by two-dimensional immunoblotting were found to recognize chromogranins/secretogranins and other unidentified proteins and to react in immunocytochemistry with pheochromocytoma as well as with a number of endocrine cells of different types. Hybridoma supernatants obtained from the splenocytes of a hyperimmune mouse, screened with an enzyme-linked immunosorbent assay, were analysed by both immunocytochemistry and two-dimensional immunoblotting. By using this experimental approach we were able to identify several monoclonal antibodies against human chromaffin granule components. In particular, we have characterized one anti-human chromogranin A and one anti-human chromogranin B/secretogranin I monoclonal antibody which showed a very specific pattern both in immunocytochemistry and in two-dimensional immunoblotting.

European multicentre study on melanoma immunoscintigraphy by means of99mTc-labelled monoclonal antibody fragments

A total of 493 melanoma patients were investigated by 20 European nuclear medicine departments by means of the saine99mTc-labelled immunoradiopharmaceutical and the same immunoscintigraphy (ISG) protocol. (i) No chemical or clinical toxicity was detected during or following the studies. (ii) Positive results were obtained in 287/363 (79%) patients (321 carrying known lesions and 42 carrying previously occult lesions): in 231 (80%) of them, 402/402 lesions were imaged, in the remaining 56 ISG-positive patients, 108/204 lesions were imaged; in 76 patients 0/122 lesions were ïmaged. (iii) The fraction of melanoma lesions visualized by ISG was 510/728 (70A%); 605 of these lesions were already documented at the time of the study, and 123 were previously occult. (iv) A total of 218 documented melanoma lesions (30%) were not visualized by ISG in 132 patients: about 70% of the ISG-negative lesions were of small size (less than 2 cm diameter). (v) The melanoma nature of 69/123 previously occult lesions was confirmed by clinical criteria and/or additional investigations in follow-up studies. The results obtained in this study are similar to those obtained in the Italian Multicentre Study which had previously been carried out with 258 melanoma patients.

In vivo imaging of chromogranin A-positive endocrine tumours by three-step monoclonal antibody targeting.

The detection of chromogranins (Cg) by immunohistochemistry and serology represents a new in vitro diagnostic tool for endocrine tumours. We have recently reported on the feasibility of targeting chromogranin A (CgA) for in vivo detection of pituitary adenomas by immunoscintigraphy (ISG). The scintigraphic procedure, based on an anti-CgA monoclonal antibody and on the avidin-biotin three-step method (Cg-3S-ISG), was evaluated on a group of 29 consecutive patients with known or suspected endocrine tumours other than pituitary adenomas, i.e. medullary thyroid carcinoma, carcinoid, insulinoma and parathormone- or ACTH-producing tumours. Primary tumours (10) and recurrences (16) were visualised in 26 patients, whereas conventional imaging techniques (planar radiography, computerised tomography, magnetic resonance imaging and ultrasonography) failed to detect the tumour sites in ten of the same (Cg-3S-ISG-positive) patients. Therefore, these preliminary results indicate that Cg-3S-ISG, the first immunological method able to detect endocrine tumours in vivo, has a higher diagnostic accuracy than conventional imaging techniques (93.1% compared with 65.5%).

Hedgehogs, humans and high‐school science

The ‘Lisbon strategy’, adopted by the member states of the European Union (EU) in 2000, aims to make Europe the most dynamic and competitive knowledge‐based economy in the world by 2010. The overall aim is to increase the levels of investment that member states put into scientific research up to and beyond 3% of their Gross Domestic Product. Although this aim will certainly not be met in the expected timeframe, it is noble and important nonetheless. > …even if the members of the EU increase investment into research, it will be in vain if they do not also work to increase the number of researchers However, even if the members of the EU increase investment into research, it will be in vain if they do not also work to increase the number of researchers. Indeed, the current number of researchers per 100,000 citizens in the EU is considerably lower than the figure for the USA or Japan. As scientists, we have virtually no possibility to influence how much money our governments spend on research and development, but we can have a much more active role in making science a more attractive career option for young people—notably high‐school students. Various projects and initiatives in EU countries and the USA have sought to achieve this aim by forging closer links between schools and universities or research institutes. Here, we describe the Cus‐Mi‐Bio (Centre University School of Milan for Bioscience Education; www.cusmibio.unimi.it) project that was developed at the University of Milano, Italy. The projects aim is to raise the levels of interest and enthusiasm of high‐school students for the life sciences, and hopefully to attract some of them to a career in science. There are various negative perceptions of science that need to be overcome when persuading students that it is a worthy career …

Characterization of Idiotypic Reagents as Antigen Surrogates of a Human Tumor-Associated Antigen

A large number of monoclonal antibodies reactive with human tumors of different histological types have been characterized (1–3) and successfully employed in tumor diagnosis in vitro (serology and immunohistochemistry) (4, 5) and in vivo (tumor imaging) (6–8); moreover, their possible use in therapy is under extensive investigation (9, 10).