Репозиторий Университета

© 2019 by the authors. Antigen-binding fragments of antibodies specific to the tumor-associated ganglioside GD2 are well poised to play a substantial role in modern GD2-targeted cancer therapies, however, rapid elimination from the body and reduced affnity compared to full-length antibodies limit their therapeutic potential. In this study, scFv fragments of GD2-specific antibodies 14.18 were produced in a mammalian expression system that specifically bind to ganglioside GD2, followed by site-directed pegylation to generate mono-, di-, and tetra-scFv fragments. Fractionated pegylated dimers and tetramers of scFv fragments showed significant increase of the binding to GD2 which was not accompanied by cross-reactivity with other gangliosides. Pegylated multimeric di-scFvs and tetra-scFvs exhibited cytotoxic effects in GD2-positive tumor cells, while their circulation time in blood significantly increased compared with monomeric antibody fragments. We also demonstrated a more efficient tumor uptake of the multimers in a syngeneic GD2-positive mouse cancer model. The findings of this study provide the rationale for improving therapeutic characteristics of GD2-specific antibody fragments by multimerization and propose a strategy to generate such molecules. On the basis of multimeric antibody fragments, bispecific antibodies and conjugates with cytotoxic drugs or radioactive isotopes may be developed that will possess improved pharmacokinetic and pharmacodynamic properties.

© 2018, Nizhny Novgorod State Medical Academy. All rights reserved. The aim of this study was to modify the chemical structure and to optimize the composition of the fibrin gel for effective cell encapsulation. Materials and Methods. We prepared PEGylated fibrin gels using different fibrinogen concentrations (25–50 mg/ml) and PEG-fibrinogen molar ratio 10:1 and 5:1 and characterized them via Fourier transform infrared spectroscopy and differential scanning calorimetry. Within the gels, we encapsulated primary culture of fibroblasts and analyzed using light and laser confocal microscopy. Results. PEGylation of fibrinogen allowed us to achieve the gel transparency and preserve its biocompatibility. We revealed that the gel prepared from PEGylated 5:1 fibrinogen (25 mg/ml) provided the most favorable microenvironment for spreading, growth, and proliferation of fibroblasts. This PEG-fibrin gel can be used for encapsulation of different cell types that is essential for various approaches in tissue engineering and diagnostic systems.