[T Lymphocytes with Modified Specificity in the Therapy of Malignant Diseases].

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.

Inhibition of P-glycoprotein stimulates cell death under Hypoxia-mimicking conditions.

The most common drug resistance mechanism in tumor cells is expression on their surface of the energy-dependent pump like P-glycoprotein (P-gp) that expels chemotherapeutic agents from the interior. An imitation of the hypoxic condition by the iron chelator deferoxamine caused Hypoxia-inducible factor 1-alpha (HIF-1α) stabilization and inhibition of doxorubicin-induced apoptosis in colon cancer НСТ116 cells. P-gp blocker verapamil suppressed doxorubicin accumulation leading to cell death induction. Considering these results, P-gp may be used as a potential target to stimulate chemotherapeutic drugs activity that will contribute to more efficient tumor cells elimination.

Recombinant MHC Tetramers for Isolation of Virus-Specific CD8+ Cells from Healthy Donors: Potential Approach for Cell Therapy of Posttransplant Cytomegalovirus Infection.

Patients undergoing allogeneic hematopoietic stem cell transplantation have a high risk of cytomegalovirus reactivation, which in the absence of T-cell immunity can result in the development of an acute inflammatory reaction and damage of internal organs. Transfusion of the virus-specific donor T-lymphocytes represents an alternative to a highly toxic and often ineffective antiviral therapy. Potentially promising cell therapy approach comprises transfusion of cytotoxic T-lymphocytes, specific to the viral antigens, immediately after their isolation from the donor's blood circulation without any in vitro expansion. Specific T-cells could be separated from potentially alloreactive lymphocytes using recombinant major histocompatibility complex (MHC) multimers, carrying synthetic viral peptides. Rapid transfusion of virus-specific T-cells to patients has several crucial advantages in comparison with methods based on the in vitro expansion of the cells. About 30% of hematopoietic stem cell donors and 46% of transplant recipients at the National Research Center for Hematology were carriers of the HLA-A*02 allele. Moreover, 94% of Russian donors have an immune response against the cytomegalovirus (CMV). Using recombinant HLA-A*02 multimers carrying an immunodominant cytomegalovirus peptide (NLV), we have shown that the majority of healthy donors have pronounced T-cell immunity against this antigen, whereas shortly after the transplantation the patients do not have specific T-lymphocytes. The donor cells have the immune phenotype of memory cells and can be activated and proliferate after stimulation with the specific antigen. Donor lymphocytes can be substantially enriched to significant purity by magnetic separation with recombinant MHC multimers and are not activated upon cocultivation with the antigen-presenting cells from HLA-incompatible donors without addition of the specific antigen. This study demonstrated that strong immune response to CMV of healthy donors and prevalence of HLA-A*02 allele in the Russian population make it possible to isolate a significant number of virus-specific cells using HLA-A*02-NLV multimers. After the transfusion, these cells should protect patients from CMV without development of allogeneic immune response.

Variability of the Phenotype and Proliferation and Migration Characteristics of Human Mesenchymal Stromal Cells Derived from the Deciduous Teeth Pulp of Different Donors.

We performed a comparative study of cell phenotype and proliferation and migration activities in vitro of mesenchymal stromal cells from human exfoliated deciduous teeth (SHED cells) from three donors. In the primary cultures, the cells of different donors had the same morphology and cytophenotype, but differed by proliferative and migration capacities. The results indicate that individual mesenchymal stromal cells cultures can differ considerably by important cell properties, and this should be considered when evaluating their potential therapeutic efficacy and in experimental studies.

Comparison of the Efficiency of Viral Transduction and Episomal Transfection in Human Fibroblast Reprogramming.

Induced pluripotent cells were derived from adult human skin fibroblast by using two methods of reprogramming. Episomal transfection with vectors containing oriP/EBNA-1 sequence for delivery of reprogramming genes Oct4, Sox2, Klf4, L-Myc, and Lin28 proved to be more effective than viral transduction with Sendai virus-based vector: ~200 and 8 colonies per 10(5) cells were found on day 21 of culturing, respectively. Colonies of induced pluripotent cells obtained by these two methods expressed pluripotency marker Tra1-60.

Comparative analysis of the expression of surface markers on fibroblasts and fibroblast-like cells isolated from different human tissues.

Expression of 20 surface markers was analyzed in cultures of mesenchymal stromal cells of the umbilical cord, fibroblasts from adult and fetal human skin, and fibroblast-like cells of fetal liver was analyzed by fl ow cytometry. The studied cultures did not express hemopoietic cells markers, but were positive for CD73, CD90, and CD105 markers recommended by the International Society of Cell Therapy for the identification of the multipotent mesenchymal stromal cells. Fetal liver fibroblast-like cells were positive for CD54; this marker was absent in skin fibroblast cultures, but was expressed by umbilical cord mesenchymal stromal cells. Further study of these cells revealed a minor subpopulation of cells co-expressing CD24 and CD90 or CD24 and CD54. We hypothesized that these cells probably participate in epithelial mesenchymal transition.