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[en] This radioimmunotrapping method for the characterization of monoclonal antibodies is briefly noted. The authors claim it overcomes the limitations of immunoblotting and immunoprecipitation. (UK)
[en] Nanoprobes are small enough to circulate within the vasculature and can reach tumour tissues through the endothelial gap, providing a new strategy for accurate tumour monitoring and imaging-guided antitumour therapy at the molecular level. Both photoacoustic and ultrasonic imaging are noninvasive tools for cancer detection via the application of nanoprobes. In this study, a polymeric multifunctional nanoparticle probe loaded with gold nanorods (Au-NRs) and liquid perfluorocarbon (perfluorinated hexane/PFH) and conjugated to a monoclonal antibody (MAGE-1 antibody) to melanoma-associated antigens (MAGE) targeting melanoma was successfully prepared by the double emulsion and carbodiimide methods as a targeted photoacoustic/ultrasound dual-mode imaging contrast agent (MAGE-Au-PFH-NPs). Cell-targeting experiments in vitro showed large amounts of MAGE-Au-PFH-NPs surrounding B16 melanoma cells in the targeted group. The photoacoustic signal in the targeted group was significantly increased, and the duration was longer than that in the untargeted group in vivo. The photoacoustic signal of the nanoprobes was enhanced with increased Au-NR concentration in the photoacoustic experiment in vitro. The enhanced signal was observed by ultrasound after 808-nm laser irradiation. A cytotoxicity and biocompatibility test showed that MAGE-Au-PFH-NPs exhibited good biological safety. The MAGE-Au-PFH-NPs can be used as a photoacoustic/ultrasound dual-mode contrast agent to lay the foundation for a promising new approach for the noninvasive targeting, monitoring and treatment of tumours.
[en] Since the description by Kohler and Milstein 1975 of their technique for producing monoclonal antibodies of predefined specificity, it has become a mainstay in most laboratories that utilize immunochemical techniques to study problems in basic, applied or clinical research. Paradoxically, the very success of monoclonal antibodies has generated a literature which is now so vast and scattered that it has become difficult to obtain a perspective. This brief review represents the distillation of many publications relating to the production and use of monoclonaal antibodies as radiopharmaceuticals. Significant advances were made possible in the last few years by combined developments in the fields of tumor-associated antigens and of monoclonal antibodies. In fact monoclonal antibodies against some well defined tumor-associated antigens, has led to significantly greater practical possibilities for producing highly specific radiolabeled antibodies as radiopharmaceuticals for diagnosis and therapy of human tumors. One of the main requirements of this methodology is the availability of stable radiopharmaceutical reagents which after labeling in vivo injection retain the capacity of specific interaction with the defined antigen and their molecular integrity. Since injection into human is the objetive of this kind of study all the specifications of radiopharmaceutical have to be fulfilled e.g. sterility, apirogenicity and absence of toxicity. (author)
[pt]Desde a descricao por Kohler e Milstein em 1975 da Tecnologia de Hibridoma e a subsequente disponibilidade de anticorpos monoclonais contra um unico determinante antigenico, estas tecnicas tornaram-se um suporte para a maioria dos laboratorios que utilizam procedimentos imunoquimicos em pesquisas basicas, aplicadas ou clinicas. Paradoxalmente, o grande sucesso dos anticorpos monoclonais gerou uma literatura vasta e dispersa dificultando o alcance de uma perspectiva. Esta concisa revisao reproduz de algumas publicacoes concernentes a producao e uso de anticorpos monoclonais como radiofarmacos. Nestes ultimos anos conseguiu-se avancos significantes com a combinacao do desenvolvimento de antigeno especifico associado a tumor e anticorpos monoclonais. De fato, anticorpos monoclonais contra alguns antigenos associados a tumor, bem definidos, codoclonais contra alguns antigenos associados a tumor, bem definidos, conduzem a possibilidade pratica de producao de anticorpos radiomarcados altamente especificos a serem usados como radiofarmacos no diagnostico e terapia de tumores humanos. A principal exigencia desta metodologia e a disponibilidade de preparacoes que, apos a marcacao e injecao in vivo, retenham a sua integridade molecular e a capacidade de interacao especifica com o antigeno definido. Tratando-se de injetaveis, devem ser preenchidas todas as especificacoes radiofarmaceuticas como esterilidade, apirogenicidade e ausencia de toxicidade. (autor)
[en] Highlights: • ReciprocalAAV1 and AAV6 variants are comparable to the WT vectors in assembly, genome titer, and transduction efficiency. • The ADK6 footprint on the AAV6 capsid identified a single residue, K531,as the determinant of recognition. • ADK6 binding overlaps previously defined AAV epitopes and is predicted to sterically hinder glycan receptor interaction. Adeno-associated viruses (AAVs) are being developed as vectors for the treatment of genetic disorders. However, pre-existing antibodies present a significant limitation to achieving optimal efficacy for the AAV gene delivery system. Efforts aimed at engineering vectors with the ability to evade the immune response include identification of residues on the virus capsid important for these interactions and changing them. Here K531 is identified as the determinant of monoclonal antibody ADK6 recognition by AAV6, and not the closely related AAV1. The AAV6-ADK6 complex structure was determined by cryo-electron microscopy and the footprint confirmed by cell-based assays. The ADK6 footprint overlaps previously identified AAV antigenic regions and neutralizes by blocking essential cell surface glycan attachment sites. This study thus expands the available repertoire of AAV-antibody information that can guide the design of host immune escaping AAV vectors able to maintain capsid functionality.
[en] Polyclonal antisera against prostaglandins (PGs) are widely used for the assessment of the biological role of these mediators, but even the most specific contain antibodies against the major metabolites and degradation products of the haptens employed. To overcome this inherent problem the authors produced monoclonal antibodies (mAs) against PGE2, PGF2α and 6-keto-PGF1α using the somatic cell hybridization technique. The mAs against 6-keto-PGF1α and PGF2α proved to be highly specific, but allowed only for moderate detection limits (1-2 ng) in conventional fluid phase radioimmunoassays (RIAs). One of the mAs against PGE2 permitted a 100-fold improvement in the detection limit while being almost devoid of cross-reactivity with metabolites and other structurally related PGs. These results show that highly specific mAs against PGs can be produced to improve the available RIA technique for PG quantification. (Auth.)
[en] Indium-111-hydroxyquinoline labelled platelets, though useful in the detection of thrombus, have not gained widespread use owing to the time and technical skill required for their preparation. A study was therefore conducted evaluating a new method of imaging thrombus with platelets radiolabelled with a 111In labelled monoclonal antibody, P256, directed to the platelet surface glycoprotein complex IIb/IIIa. When the number of receptors occupied by P256 was less than 3% of the total available on the platelet surface platelet function, as assessed by platelet aggregometry, was undisturbed. P256 was radiolabelled with 111In using diethylenetriaminepenta-acetic acid, which achieved a specific activity of 185 MBq (5 mCi)/mg. No impairment of immunoreactivity was detected at this specific activity. Platelets were labelled with radiolabelled monoclonal antibody in vitro in two patients at a receptor occupancy of 6% and in vivo - that is, by direct intravenous injection of P256 - in six patients at a receptor occupancy of 1%. In vivo recovery and biodistribution kinetics suggested that after in vitro labelling platelets were minimally activated. The 111In kinetics recorded after intravenous P256 suggested rapid and efficient radiolabelling of platelets and gave no indication of platelet activation. Of the six patients who received intravenous P256, three had documented thrombus, tow of whom gave positive results on P256 platelet scintigraphy. The third subject had chromic deep venous thrombosis and was scintigraphically negative. Imaging thrombus using a radiolabelled monoclonal antibody directed to platelets appears to offer great potential as a simple, non-invasive approach to the diagnosis of thrombosis. 3 refs. (Author)
[en] In immunoscintigraphy a radiolabeled monoclonal antibody is used for 'antigen imaging'. Application of either intact antibody or fragments and labelling of the antibody with different radionuclides will result in a significant change of the protocol of examination. Potential allergic reactions may restrict the unlimited repetition of these techniques. The approach and adequate binding of the antibody to the specific antigen define indication of immunoscintigraphy. Results will be improved significantly by using modern nuclear medicine equipment like SPECT-technique. Careful selection of patients for immunoscintigraphy is recommended to obtain the most benefit from these new nuclear medicine techniques. (Author)
[en] Eighteen chapters review the use of monoclonal antibodies for cancer detection and therapy. Eleven chapters covering various different types of antibodies used for a range of cancers, developments in antibody imaging in the radioimmunodetection of tumours and the use of radiolabelled antibodies in cancer radiotherapy were selected and indexed separately. (UK)