Том 51, № 6 (2017)

Over the last forty years, recombinant antibodies have been transformed from an unproven experimental approach to a therapeutic modality with multiple success stories in the treatment of cancer, inflammation, infections and cardiometabolic diseases. Owing to their high affinity and selectivity for the target antigen, their multimodal tunable mode of action, their modular nature and long half-life, antibodies now hold prominent positions in the pipelines of major biopharmaceutical companies. In this brief report, I aim to highlight the themes that have shaped the therapeutic antibody engineering as it exists today and to offer a personal perspective on its future developments. Distinct antibody engineering history, developments and trends in Russian Federation will not be discussed since they are detailed elsewhere in this journal issue.

In this review, the authors' works published within the past 5 years devoted to the development of bifunctional hybrid nanostructures based on the targeting polypeptides and nanoparticles of various origin (quantum dots, nanogold, nanodiamonds, upconversion nanoparticles, magnetic and polymer nanoparticles) as modules that ensure visualization and various damaging effects on cancer cells are surveyed and the prospects of their application in theranostics and precision medicine have been contemplated.

Intestinal microbiota controls multiple aspects of body homeostasis. The microbiota composition changes easily in response to internal or external factors, which may result in dysbiosis and associated inflammatory reactions. Thus, maintaining the microbiota composition by the host immune system is crucial, and one of the main mechanisms for microbiota control is production of immunoglobulin A (IgA) at mucosal surfaces. The molecular mechanisms regulating the interactions between the immune system and microbiota remain obscure. A panel of hybridoma cell lines was constructed to produce monoclonal IgA antibodies specific to various commensal bacteria present in intestinal microbiota. The panel can be used to further understand the mechanisms whereby the adaptive immune system controls the microbiota composition.

Catalytic antibodies are a promising model for creating highly specific biocatalysts with predetermined activity. However, in order to realize the directed change or improve their properties, it is necessary to understand the basics of catalysis and the specificity of interactions with substrates. In the present work, a structural and functional study of the Fab fragment of antibody A5 and a comparative analysis of its properties with antibody A17 have been carried out. These antibodies were previously selected for their ability to interact with organophosphorus compounds via covalent catalysis. It has been established that antibody A5 has exceptional specificity for phosphonate X with bimolecular reaction rate constants of 510 ± 20 and 390 ± 20 min^–1M^–1 for kappa and lambda variants, respectively. 3D-Modeling of antibody A5 structure made it possible to establish that the reaction residue L-Y33 is located on the surface of the active site, in contrast to the A17 antibody, in which the reaction residue L-Y37 is located at the bottom of a deep hydrophobic pocket. To investigate a detailed mechanism of the reaction, A5 antibody mutants with replacements L-R51W and H-F100W were created, which made it possible to perform stopped-flow kinetics. Tryptophan mutants were obtained as Fab fragments in the expression system of the methylotrophic yeast species Pichia pastoris. It has been established that the effectiveness of their interaction with phosphonate X is comparable to the wild-type antibody. Using the data of the stopped-flow kinetics method, significant conformational changes were established in the phosphonate modification process. The reaction was found to proceed using the induced-fit mechanism; the kinetic parameters of the elementary stages of the process have been calculated. The results present the prospects for the further improvement of antibody-based biocatalysts.

A new efficient method for the parallel and sequential stepwise generation of single-domain antibodies to various high-abundance human-plasma proteins has been described. Single-domain antibodies have a number of features that favorably distinguish them from classical antibodies. In particular, they are able to recognize unusual unique conformational epitopes of native target proteins, small in size, and relatively easily produced and modified; have enhanced stability; and rapidly renature after denaturation. As a consequence, the immunosorbents that utilize these antibodies can be reused without any significant loss of activity. The principal novelty and universality of the described method is that it enables the sequential generation of antibodies to a number of high-abundance and yet unknown antigens of a complex protein mixture without the need for purified antigens. The effectiveness of the method is demonstrated by the example of generation of single-domain antibodies to a number of high-abundance proteins of the human blood plasma. The produced antibodies are promising biotechnological tools that can be used to develop prototypes for new diagnostic and therapeutic agents, as well as appropriate immunoaffinity-based methods for removal, enrichment, analysis, and/or targeting of specified proteins and their complexes from (in) the human blood. As we show, the generated single-domain antibodies can be efficiently used in designing new immunosorbents. As a rule, commercially available analogous immunosorbents that utilize classical antibodies remove many major proteins from the blood plasma immediately, while immunosorbents for many individual proteins are difficult to find and rather expensive. Single-domain antibodies generated by our method are unique new materials that allow for the development of more efficient and delicate approaches to pretreatment of plasma and the analysis of various blood plasma biomarkers.

Immunotherapy is one of the most rapidly progressing and promising fields in antitumor therapy. It is based on the idea of using immune cells of patient or healthy donors for elimination of malignant cells. T lymphocytes play a key role in cell-mediated immunity including the response to tumors. Recently developed approaches of altering antigen specificity of T cells consist of their genetic modification (introduction of additional T cell receptor or chimeric antigen receptor), as well as the use of bispecific molecules that crosslink target and effector cells. These approaches are used to retarget T lymphocytes with arbitrary specificity against tumor antigens in the context of antitumor immunotherapy. The high potential of T cell immunotherapy was demonstrated in a number of clinical trials. In the future, it is possible to develop approaches to the therapy of a wide spectrum of tumors. The selection of the optimal antigen is the main challenge in successful T cell immunotherapy, as it largely determines the effectiveness of the treatment, as well as the risk of side effects. In this review we discuss potential methods of modification of T cell specificity and targets for immunotherapy.

The late 1970s brought opportunities to create proteins with new properties and, in particular, various derivatives of mouse monoclonal antibodies (mAbs) owing to the discoveries in molecular and cell biology and the development of bioengineering. Studies of mouse/human “chimeric” antibodies, miniantibodies to be synthesized in bacterial cells, full-size single-chain antibodies, complexes of miniantibodies with intramolecular chaperones, and other approaches made it possible to create a multitude of multifunctional biopreparations with predefined properties. The review describes, with the example of one research team, how studies in the field began and what the basis for their progress was.

Tumor necrosis factor (TNF) is a proinflammatory cytokine implicated in pathogenesis of multiple autoimmune and inflammatory diseases. Anti-TNF therapy has revolutionized the therapeutic paradigms of autoimmune diseases and became one of the most successful examples of the clinical use of monoclonal antibodies. Currently, anti-TNF therapy is used by millions of patients worldwide. At the moment, fully human anti-TNF antibody Adalimumab is the best-selling anti-cytokine drug in the world. Here, we present a story about a highly potent anti-TNF monoclonal antibody initially characterized more than 20 years ago and further developed into chimeric and humanized versions. We present comparative analysis of this antibody with Infliximab and Adalimumab.