ABSTRACT
Internalization of liposomal nanocontainers conjugated with monoclonal antibodies to VEGF, VEGFR2 (KDR), and proteins overproduced in the tumor tissue was studied in vitro on cultures of poorly differentiated tumor cells. Comparative analysis of accumulation of vectored liposomes in the tumor cells was performed by evaluating co-localization of labeled containers and cell organelles by laser scanning confocal microscopy. We observed nearly 2 times more active penetration and accumulation of liposomes vectored with antibodies in the tumor cells in comparison with non-vectored liposomes. Selective clathrin-dependent penetration of vectored liposomes into tumor cells was demonstrated by using pharmacological agents inhibiting endocytosis.
Subject(s)
Antibodies, Monoclonal/chemistry , Liposomes/chemistry , Liposomes/metabolism , Animals , Antibodies, Monoclonal/immunology , Cell Line, Tumor , Glioma/metabolism , Microscopy, Confocal , Rats , Vascular Endothelial Growth Factor A/immunologyABSTRACT
The tumor-suppressive effect of rat mesenchymal stem cells against low-differentiated rat C6 glioma cells during their direct and indirect co-culturing and during culturing of C6 glioma cells in the medium conditioned by mesenchymal stem cells was studied in an in vitro experiment. The most pronounced antitumor activity of mesenchymal stem cells was observed during direct co-culturing with C6 glioma cells. The number of live C6 glioma cells during indirect co-culturing and during culturing in conditioned medium was slightly higher than during direct co-culturing, but significantly differed from the control (C6 glioma cells cultured in medium conditioned by C6 glioma cells). The cytotoxic effect of medium conditioned by mesenchymal stem cells was not related to medium depletion by glioma cells during their growth. The medium conditioned by other "non-stem" cells (rat astrocytes and fibroblasts) produced no tumor-suppressive effect. Rat mesenchymal stem cells, similar to rat C6 glioma cells express connexin 43, the main astroglial gap junction protein. During co-culturing, mesenchymal stem cells and glioma C6 cells formed functionally active gap junctions. Gap junction blockade with connexon inhibitor carbenoxolone attenuated the antitumor effect observed during direct co-culturing of C6 glioma cells and mesenchymal stem cells to the level produced by conditioned medium. Cell-cell signaling mediated by gap junctions can be a mechanism of the tumor-suppressive effect of mesenchymal stem cells against C6 glioma cells. This phenomenon can be used for the development of new methods of cell therapy for high-grade malignant gliomas.
Subject(s)
Brain Neoplasms/pathology , Cell Communication/physiology , Glioma/pathology , Mesenchymal Stem Cells/metabolism , Signal Transduction/physiology , Animals , Antineoplastic Agents , Cell Differentiation , Cell Line, Tumor , Cell Movement , Cell- and Tissue-Based Therapy , Coculture Techniques , Culture Media, Conditioned/pharmacology , Rats , Rats, Wistar , Tight Junctions/physiologyABSTRACT
Synthetic Salmonella O-antigens of a new copolymeric type, unlike natural antigens (lipopolysaccharides), exhibit monospecificity for groupspecific factors 0 : 3, 0 : 4, and 0 : 9 of Salmonella serogroups E, B, and D, and are, by 1-2 orders of magnitude, more sensitive in double immunodiffusion and passive hemagglutination inhibition tests. The use of the synthetic antigens for detection of antibodies in patients' sera by means of passive hemagglutination increased the specificity of this test considerably, thereby improving immunodiagnosis of salmonellosis.
Subject(s)
Antibodies, Bacterial/analysis , Antigens, Bacterial , Hemagglutination Tests , Oligosaccharides , Salmonella Infections/diagnosis , Salmonella/immunology , Animals , Antigens, Bacterial/chemical synthesis , Carbohydrate Sequence , Humans , Immune Sera , Immunodiffusion , Lipopolysaccharides/immunology , Molecular Sequence Data , O Antigens , Oligosaccharides/chemical synthesis , Rabbits , Salmonella/classification , Salmonella Infections/immunologyABSTRACT
The synthesis of a new type of synthetic antigen that contains no protein is described. Two linear polyacrylamide copolymers with carbohydrate branches were obtained via radical copolymerisation of the allyl glycosides of the oligosaccharide determinants O-beta-D-mannopyranosyl-(1----4)-O-alpha-L-rhamnopyranosyl-(1----3 )-beta-D- galactopyranose and O-3,6-dideoxy-alpha-D-xylo-hexopyranosyl-(1----3)-alpha-D-mannopyranose with acrylamide. These copolymers, which contained 30% of carbohydrate and had molecular masses exceeding 100 kilodaltons, had the group specificity E and B of Salmonella.