Chain centricity is a feature of some T cell receptors (TCRs), in which one hemi-chain (α or β) dominates in antigen recognition. The exact proportion of chain-centric TCRs in the native repertoire is currently unknown, as is their inclusion in the repertoires of different functional T cell subsets. Discovering these main issues will elucidate the origin of chain-centric clonotypes and greatly improve their detection in bulk repertoires. In this work, the frequency and abundance of clonotypes with the dominant-active α-chain TCR (TCRα), i.e., α-chain-centric clonotypes, were identified in the mouse repertoires of primarily activated effectors and reactivated memory cells specific to tumor alloantigens. Screening tests in vitro showed that α-chain-centric clonotypes were contained in both repertoires, indicating that α-chain centricity could be an inherent feature of some TCRs. In both repertoires, the proportions of such clonotypes were found to be 20% to 25% of clonotypes expanded during antigenic stimulation. Transduction of naïve T cells with the individual dominant-active TCRα from both repertoires generated cytotoxic effectors that specifically killed the cognate tumor cells in vitro. This study confirmed previous findings that T cell modification with TCRα of α-chain-centric clonotypes generated functionally active antigen-specific effectors. Clonotypes with the dominant-active TCRα were actively involved in the primary allogeneic response. In contrast to primarily activated effectors, α-chain-centric memory clonotypes had the complementarity-determining region 3 (CDR3) with the unique physicochemical signature of shorter length, increased charge, and lower volume and polarity. Here, α-chain-centric memory clonotypes were proposed as promising candidates for adoptive TCR-T cell therapy.

Cold tumors have an immunosuppressive microenvironment (TME) with weak infiltration of functionally active NK and T cells. Such tumors poorly respond to immunotherapies, and different combined approaches are investigated to reprogram cold tumors into hot ones and improve treatment efficacy. The search for novel immunostimulatory factors for the therapy of cold tumors is of particular clinical relevance. Previously, we showed the antitumor effects of recombinant human Cyclophilin A (rhCypA), an analog of proinflammatory secretory CypA, in experimental models in vivo and indicated it as a stimulator of the antitumor immune response and a modulator of the immune TME. In this study, the effect of rhCypA on the functionality of tumor-infiltrating NK and T cells was investigated using the melanoma B16 tumor model in vivo . After rhCypA treatment, T cells in the TME differently expressed the transcription factors Tbet and Eomes and the exhaustion markers PD-1, LAG-3, and TIM3. Tumors of rhCypA-dosed mice contained a higher proportion of activated CD4 + CD25 + T cells and CD8 + T cells with upregulated activation markers CD44 and CD25 and co-stimulatory CD28. Similarly, rhCypA upregulated PD-1, CTLA-4, and CD25 and downregulated exhaustion markers KLRG-1 and LAG-3 in tumor-infiltrating NK cells. After rhCypA treatment, melanoma B16 was actively infiltrated with CD8 + T cells and NK cells with increased perforin and granzyme B production and TNFα-producing CD4 + cells. Thus, rhCypA reprogrammed the immune tumor microenvironment by boosting the accumulation of functionally more active NK and T cells with the enhanced production of cytotoxic factors while modulating their dysfunction and weakening immunosuppression.

T cells, the adaptive immunity effectors, carry an antigen-recognizing T-cell receptor (TCR) that represents an alpha(3 heterodimer. Functional dominance of one chain has been reported for a number of TCRs. This feature is called chain centricity. Today, it is unclear whether chain centricity is an inherent feature of some TCRs, and what mechanism underlies its development. The study aimed to determine the abundance of such receptors in the repertoire of primarily activated effectors and re-stimulated memory cells of mice specific to the allogeneic tumor antigens. The long-lived memory cells formed in the primary immune response in vivo were in vitro re-stimulated with the immunizing tumor cells. Primary effectors were obtained in vitro in the culture by stimulation of T cells of non-immunized mice with cells of the same allogeneic tumor. TCR libraries of effectors involved in the primary and secondary immune response were created by NGS sequencing. To identify chain-centric TCRs, 10 & Tcy;CR alpha variants were selected from each repertoire. T cells of intact mice were modified with individual TCR alpha-chain variants by transduction, with subsequent assessment of T cell proliferation under exposure to specific allogeneic stimulators. In vitro screening revealed 10% of chain-centric receptors in the primary effector pool, and the proportion of such TCRs in the repertoire of re-activated memory cells was 30%. Thus, chain centricity is an inherent property of some TCRs, but secondary antigenic stimulation can be a factor for selection of clonotypes with such receptors.

Contacts: Maria Anatolievna Zamkova zamkovam@gmail.com Introduction. Due to the toxicity of high doses of chemotherapy, low concentrations used in cancer treatment leads to the development of senescence phenotype in tumor cells, characterized by a block in the cell cycle progression and the absence of division; changes in the transcriptional and metabolic profile of cells. A negative consequence of this stage is acquisition of individual cells the ability to escape from senescence and return to re-proliferation.Aim. To estimate the effect of the duration of drug treatment of HCT116 tumor cells on their ability to escape from therapy induced senescence.Materials and methods. The senescence phenotype was confirmed by the analysis of β-galactosidase activity; cell cycle analysis; estimation of protein levels by western blotting. Colonies were stained with crystal violet dye.Results. In our study, we showed that the duration of HCT116 cells incubation with low-dose doxorubicin affects their ability to return to re-proliferation – increasing the treatment time using same drug dose reduces the process of colony formation. The duration of doxorubicin treatment does not affect the formation of the senescence phenotype, which was confirmed by analyzing different markers of this stage (changes in β-galactosidase activity, cell cycle analysis, assessment of p21 and γH2AX protein levels). However, there is a delay in the development of cellular response to DNA damage caused by doxorubicin in cells exposed to prolong treatment protocol (increase in β-galactosidase activity, formation of polyploid cells).Conclusion. The duration of doxorubicin treatment of HCT116 cancer cells affects long-term consequences, reducing the ability of senescent cells to escape this stage when the incubation time with the drug is extended.

This study analyzed tumor-associated inflammation by assessing the expression of cyclophilin A (CypA) and TNF in samples of kidney tumors of various histological types. It was shown that different histological types of renal cell carcinoma differed by the expression of these proteins. Thus, the highest expression of CypA and TNF was observed in papillary and chromophobe kidney cancer, although no correlation with overall bacterial load was found for these tumors. In the case of clear cell renal cell carcinoma, the expression of proinflammatory factors was observed in only half of the cases and directly correlated with the presence of resident bacteria, serving as a favorable prognostic factor for the disease.

PurposeDifferent regimens of low-dose chemotherapy (LDC) are currently being actively developed and introduced into clinical practice. Along with its obvious advantages compared to conventional chemotherapy (low toxicity, prevention of drug resistance), LDC could also stimulate anti-tumor immune responses in a patient by activating effectors of innate and adaptive immunity and diminishing tumor-associated immunosuppression. As non-myeloablative, LDC could be successfully combined with different anti-cancer immunotherapeutic strategies, including immunoregulatory cytokines. Secreted cyclophilin A (CypA) is of particular interest in this respect. Previously, we showed that recombinant human CypA (rhCypA) had pleiotropic immunostimulatory activity and anti-tumor effects. Thus, rhCypA could be potentially proposed as a perspective component of combined therapy with LDC.MethodsIn this work, we evaluated the anti-tumor effects of rhCypA combined with low doses of cyclophosphamide, doxorubicin, dacarbazine, and paclitaxel in the experimental mouse tumor models of melanoma B16 and lymphoma EL4 in vivo.ResultsSynergic and potentiating effects of rhCypA combined with LDC were shown in these studies. Furthermore, as a monotherapeutic agent and a component of combined chemoimmunotherapy, rhCypA was shown to modulate the immune tumor microenvironment by enhancing tumor infiltration with macrophages, NK cells, and T cells. It was also found that rhCypA stimulated both systemic and local anti-tumor immune responses.ConclusionRhCypA could be potentially proposed as a perspective component of the combined cancer chemoimmunotherapy.

Introduction. Immune checkpoint inhibitors have an exceptional position in cancer immunotherapy. Currently, anti-CTLA-4 (cytotoxic T-lymphocyte-associated protein 4) and anti-PD-1/PD-L1 (PD-1 – programmed cell death 1, PD-L1 – programmed death 1 ligand 1) therapies are most widely applied in clinical practice. Still, immune checkpoint inhibitors therapy is not always successful, and multiple studies have indicated that it should be combined with other immunotherapeutic strategies, including cytokines. Secreted cyclophilin A (CypA) could be of particular interest in this respect. Previously, we showed that recombinant human CypA (rhCypA) had pleiotropic immunostimulatory activity and anti-tumor effects. Studies of rhCypA as an anti-cancer factor pointed to its potential use in cancer chemoimmunotherapy and combination immunotherapy.Aim. To evaluate anti-tumor effects of combined immunotherapy using rhCypA and immune checkpoint inhibitors in the mouse model of melanoma B16 in vivo.Materials and methods. C57BL/6 mice were subcutaneously transplanted with melanoma B16. On days 6 and 9 posttumor transplantation, monoclonal antibodies to PD-1, PD-L1 and programmed cell death 1 ligand 2 (PD-L2), CTLA-4, lymphocyte-activation gene 3 (LAG-3), or CD276 were intravenously injected into mice at a dose of 100 μg/mouse. RhCypA was injected s/c on days 6–10 post-tumor transplantation at a dose of 100 μg/mouse. The therapeutic effects of combined immunotherapy were evaluated by melanoma B16 growth dynamics and the survival of tumor-bearing mice.Results. In combination with anti-CTLA-4 monoclonal antibodies, rhCypA had the most distinct and prolonged synergic anti-tumor effects until day 19 post-immunotherapy, with an increase in animal lifespan of 70 %. When used with anti-LAG-3 monoclonal antibodies, rhCypA exhibited a synergic therapeutic effect by day 12 post-therapy. Combination of rhCypA with anti-PD-L1 or anti-CD276 monoclonal antibodies had short-term synergic effects until day 5 after therapy. Recombinant human CypA impeded the anti-tumor effects of dual anti-PD-1 + anti-LAG-3 therapy.Conclusion. Our findings pointed out that rhCypA could significantly improve therapeutic effects of individual immune checkpoint inhibitors. Therefore, rhCypA could be potentially proposed as a component of combined anti-tumor immunotherapy.

T cell engineering with T cell receptors (TCR) specific to tumor antigens has become a breakthrough towards personalized cancer adoptive cell immunotherapy. However, the search for therapeutic TCRs is often challenging, and effective strategies are strongly required for the identification and enrichment of tumor-specific T cells that express TCRs with superior functional characteristics. Using an experimental mouse tumor model, we studied sequential changes in TCR repertoire features of T cells involved in the primary and secondary immune responses to allogeneic tumor antigens. In-depth bioinformatics analysis of TCR repertoires showed differences in reactivated memory T cells compared to primarily activated effectors. After cognate antigen re-encounter, memory cells were enriched with clonotypes that express α-chain TCR with high potential cross-reactivity and enhanced strength of interaction with both MHC and docked peptides. Our findings suggest that functionally true memory T cells could be a better source of therapeutic TCRs for adoptive cell therapy. No marked changes were observed in the physicochemical characteristics of TCRβ in reactivated memory clonotypes, indicative of the dominant role of TCRα in the secondary allogeneic immune response. The results of this study could further contribute to the development of TCR-modified T cell products based on the phenomenon of TCR chain centricity.

Cyclophilin A (CypA) is an isomerase that functions as a chaperone, housekeeping protein, and cyclosporine A (CsA) ligand. Secreted CypA is a proinflammatory factor, chemoattractant, immune regulator, and factor of antitumor immunity. Experimental data suggest clinical applications of recombinant human CypA (rhCypA) as a biotherapeutic for cancer immunotherapy, stimulation of tissue regeneration, treatment of brain pathologies, and as a supportive treatment for CsA-based therapies. The objective of this study is to analyze the pharmacokinetics of rhCypA in a mouse model. rhCypA was isotope-labeled with 125I and injected intraperitoneally (i.p.) or subcutaneously (s/c) into female mice as a single dose of 100 μg per mouse, equivalent to the estimated first-in-human dose. Analysis of 125I-rhCypA biodistribution and excretion was performed by direct radiometry of the blood, viscera, and urine of mice 0.5–72 h following its administration. rhCypA showed rapid and even tissue–organ distribution, with the highest tropism (fT = 1.56) and accumulation (maximum concentration, Cmax = 137–167 μg/g) in the kidneys, its primary excretory organ. rhCypA showed the lowest tropism to the bone marrow and the brain (fT = 0.07) but the longest retention in these organs [mean retention time (MRT) = 25–28 h]. This study identified promising target organs for rhCypA’s potential therapeutic effects. The mode of rhCypA accumulation and retention in organs could be primarily due to the expression of its receptors in them. For the first time, rhCypA was shown to cross the blood–brain barrier and accumulate in the brain. These rhCypA pharmacokinetic data could be extrapolated to humans as preliminary data for possible clinical trials.

T cells are crucial players in adaptive anti-cancer immunity. The gene modification of T cells with tumor antigen-specific T cell receptors (TCRs) was a milestone in personalized cancer immunotherapy. TCR is a heterodimer (either α/β or γ/δ) able to recognize a peptide antigen in a complex with self-MHC molecules. Although traditional concepts assume that an α- and β-chain contribute equally to antigen recognition, mounting data reveal that certain receptors possess chain centricity, i.e., one hemi-chain TCR dominates antigen recognition and dictates its specificity. Chain-centric TCRs are currently poorly understood in terms of their origin and the functional T cell subsets that express them. In addition, the ratio of α- and β-chain-centric TCRs, as well as the exact proportion of chain-centric TCRs in the native repertoire, is generally still unknown today. In this review, we provide a retrospective analysis of studies that evidence chain-centric TCRs, propose patterns of their generation, and discuss the potential applications of such receptors in T cell gene modification for adoptive cancer immunotherapy.

Adoptive T-cell therapy (ACT) is successfully applied in cancer treatment; however, its efficiency can be limited by a low viability, short persistence time, and loss of functional activity of T-cells after adoptive transfer. The search for novel immunomodulators that can improve the viability, expansion, and functions of T-cells after their infusion with the minimal side effects could contribute to the development of more efficient and safe ACT strategies. Recombinant human cyclophilin A (rhCypA) is of particular interest in this respect, as it exhibits pleiotropic immunomodulatory activity and stimulates both innate and adaptive anti-tumor immunity. Here, we evaluated the effect of rhCypA on the efficacy of ACT in the mouse EL4 lymphoma model. Lymphocytes from transgenic 1D1a mice with an inborn pool of EL4-specific T-cells were used as a source of tumor-specific T-cells for ACT. In models of immunocompetent and immunodeficient transgenic mice, the course (3 days) rhCypA administration was shown to significantly stimulate EL4 rejection and prolong the overall survival of tumor-bearing mice after adoptive transfer of lowered doses of transgenic 1D1a cells. Our studies showed that rhCypA significantly improved the efficacy of ACT by enhancing the effector functions of tumor-specific cytotoxic T-cells. These findings open up the prospects for the development of innovative strategies of adoptive T-cell immunotherapy for cancer using rhCypA as an alternative to existing cytokine therapies.

The precise balance of Th1, Th2, and Th17 cytokines is a key factor in successful pregnancy and normal embryonic development. However, to date, not all humoral factors that regulate and influence physiological pregnancy have been completely studied. Our data here pointed out cyclophilin A (CypA) as the adverse pro-inflammatory factor negatively affecting fetal development and associated with pregnancy complications. In different mouse models in vivo, we demonstrated dramatic embryotoxicity and teratogenicity of increased CypA levels during pregnancy. Using generated transgenic models, we showed that CypA overexpression in fetal tissues induced the death of all transgenic fetuses and complete miscarriage. Administration of recombinant human CypA in a high dose to pregnant females during fetal organogenesis (6.5-11.5 dpc) exhibited teratogenic effects, causing severe defects in the brain and bone development that could lead to malformations and postnatal behavioral and cognitive disorders in the offspring. Embryotoxic and teratogenic effects could be mediated by CypA-induced up-regulation of M1 macrophage polarization via activation of the STAT1/3 signaling pathways. Here, we propose secreted CypA as a novel marker of complicated pregnancy and a therapeutic target for the correction of pregnancy complications.

Chronic inflammation is associated with malignant transformation and creates the microenvironment for tumor progression. Cyclophilin A (CypA) is one of the major pro-inflammatory mediators that accumulates and persists in the site of inflammation in high doses over time. According to multiomics analyses of transformed cells, CypA is widely recognized as a pro-oncogenic factor. Vast experimental data define the functions of intracellular CypA in carcinogenesis, but findings on the role of its secreted form in tumor formation and progression are scarce. In the studies here, we exploit short-term in vitro and in vivo tests to directly evaluate the mutagenic, recombinogenic, and blastomogenic effects, as well as the promoter activity of recombinant human CypA (rhCypA), an analogue of secreted CypA. Our findings showed that rhCypA had no genotoxicity and, thus, was neither involved in nor influenced the initiation stage of carcinogenesis. At high doses, rhCypA could disrupt gap junctions in rat liver epithelial IAR-2 cells in vitro by decreasing the expression of connexins 26 and 43 in these cells and inhibit A549 cell adhesion. These data suggested that rhCypA could contribute to epithelial-mesenchymal transition in malignant cells. The research presented here elucidated the role of secreted CypA in carcinogenesis, revealing that it is not a tumor initiator but can act as a tumor promoter at high concentrations.

Introduction. Current approaches are being developed for adoptive cancer therapy using T-cells genetically modified with T-cell receptors (TCRs) with specificity for tumor antigens. The complexities of identifying antigen-specific TCRs in a patient’s repertoire and selecting therapeutic receptors necessitate the development of experimental strategies for generating tumor-specific T cells. One of such approaches could be the xenogeneic immunization of mice with human tumor cells. It seems plausible that the T cell repertoire stimulated by xenogeneic vaccination could be a source of TCRs suitable for adoptive cancer immunotherapy.Aim. To assess the prospects for using xenogeneic immunizations to generate tumor-specific memory T cells and identify their TCRs suitable for adoptive immunotherapy, we studied the dynamics of the secondary xenogeneic response in a model of induction of an immune response in mice to human melanoma cells.Materials and methods. Mice were immunized with human melanoma cells, and 45 days later, they were re-challenged with the immunizing tumor. The dynamics of the development of the secondary immune response in vivo and the composition of the involved effectors of adaptive immunity were analyzed by flow cytometry. The proliferation of lymphocytes from immune mice in response to human melanoma cells was evaluated in in vitro culture.Results. The secondary xenogeneic response was characterized by a more intense accumulation of T cells and the rapid development of the effector phase at the injection site of human melanoma. This correlated with an enhanced in vitro proliferative response of lymphocytes from immune animals to xenoantigens of the immunizing tumor. CD4+ and CD8+ memory T cells contributed equally to the development of a secondary response to human melanoma cells expressing HLA class I and II molecules. When only HLA class I was expressed on the cells of the immunizing xenogeneic tumor, CD8+ memory cells were formed, which dominated the secondary immune response.Conclusion. Our findings confirmed the formation of a specific immunological memory for xenoantigens during xenogeneic immunization. This suggests the possibility of generating xenogeneic TCRs specific for human tumor antigens, which opens up opportunities to developing approaches for screening among them for receptor variants suited for adoptive immunotherapy of human cancers.

A T cell receptor (TCR) consists of α- and β-chains. Accumulating evidence suggests that some TCRs possess chain centricity, i.e., either of the hemi-chains can dominate in antigen recognition and dictate the TCR's specificity. The introduction of TCRα/β into naive lymphocytes generates antigen-specific T cells that are ready to perform their functions. Transgenesis of the dominant active TCRα creates transgenic animals with improved anti-tumor immune control, and adoptive immunotherapy with TCRα-transduced T cells provides resistance to infections. However, the potential detrimental effects of the dominant hemi-chain TCR's expression in transgenic animals have not been well investigated. Here, we analyzed, in detail, the functional status of the immune system of recently generated 1D1a transgenic mice expressing the dominant active TCRα specific to the H2-Kb molecule. In their age dynamics, neither autoimmunity due to the random pairing of transgenic TCRα with endogenous TCRβ variants nor significant disturbances in systemic homeostasis were detected in these mice. Although the specific immune response was considerably enhanced in 1D1a mice, responses to third-party alloantigens were not compromised, indicating that the expression of dominant active TCRα did not limit immune reactivity in transgenic mice. Our data suggest that TCRα transgene expression could delay thymic involution and maintain TCRβ repertoire diversity in old transgenic mice. The detected changes in the systemic homeostasis in 1D1a transgenic mice, which are minor and primarily transient, may indicate variations in the ontogeny of wild-type and transgenic mouse lines.

Adoptive cell therapy (ACT) based on TCR- or CAR-T cells has become an efficient immunotherapeutic approach for the treatment of various diseases, including cancer. Previously, we developed a novel strategy for generating therapeutic T cell products based on chain-centric TCRs, in which either α- or β-chain dominates in cognate antigen recognition. To assess the suitability of our experimental approach for the clinical application and predict its possible adverse effects, in studies here, we evaluated the safety of the experimental TCRα-modified T cell product in mouse preclinical models. Our data showed no tumorigenic or mutagenic activity in vitro of TCRα-transduced T cells, indicating no genotoxicity of viral vectors used for the generation of the experimental T cell product. Adoptive transfer of TCRα-engineered T cells in a wide dose range didn`t disturb the host homeostasis and exhibited no acute toxicity or immunotoxicity in vivo. Based on pharmacokinetics and pharmacodynamics analysis here, modified T cells rapidly penetrated and distributed in many viscera after infusion. Histological evaluations revealed no pathological changes in organs caused by T cells accumulation, indicating the absence of non-specific off-target activity or cross-reactivity of the therapeutic TCRα. Studies here provide valuable information on the potential safety of TCRα-T cell based ACT that could be extrapolated to possible effects in a human host.

In this work, we developed the method of preparative production of recombinant human cyclophilin A (rhCypA) in Escherichia coli. The full-length cDNA encoding the gene of human CypA (CYPA) was amplified by RT-PCR from the total RNA of human T cell lymphoma Jurkat. The nucleotide sequence of CYPA was optimized to provide highly effective translation in E. coli. Recombinant CYPA DNA was cloned into the pET22b(+) vector, and the resulted expression plasmid was used to transform E. coli strain BL21(DE3)Gold. The recombinant producer strain of E. coli produced soluble rhCypA in the bacterial cytoplasm. The synthesis efficiency of rhCypA was up to 50% of the total cell protein allowing to produce rhCypA in the amount of 1 g per liter of the culture. We also developed the method for rhCypA purification, consisting of a single-step tandem anion exchange chromatography on DEAE- and Q-Sepharose columns. The protein purity was 95% according to electrophoresis (SDS-PAGE), and its contamination with endotoxin did not exceed 0.05 ng per 1 mg of the protein that met the requirements of European pharmacopoeia for injectable preparations. The produced recombinant protein exhibited functional features of native CypA, i.e., isomerase activity and chemokine activity as assessed by stimulation of migration of mouse bone marrow hematopoietic stem cells in vivo. The generated producer strain of E. coli is a super-producer and could be used for large-scale experimental studies of rhCypA and in its preclinical and clinical trials as a drug.

Under conditions of lymphopenia, T lymphocytes proliferate and acquire a surface activation phenotype, which in many respects is similar to the phenotype of true memory T cells. We investigated the phenotypic features of the CD8+ T-cell population formed from donor lymphocytes after adoptive transfer of syngeneic splenocytes to sublethally irradiated mice. This population expresses markers CD44, CD122, CD5, CD49d and the chemokine receptor CXCR3. Thus, for the first time, the phenomenon of the formation of a population of T cells with signs of suppressive CD8+ T lymphocytes and true memory cells was demonstrated.

Cyclophilin A (CypA) is a pro-inflammatory factor with multiple immunomodulating effects. Here, we investigated the effects of recombinant human CypA (rhCypA) as a factor of antitumor host defense. Our results demonstrated that rhCypA dramatically inhibited the growth of murine transplantable tumors (mammary adenocarcinoma Ca755, melanoma B16, Lewis lung carcinoma (LLC), and cervical cancer CC-5). In the B16 model, rhCypA effects were observed only when tumor cells were transplanted at the significantly reduced injection dose, indicating that antitumor properties of rhCypA are more effective at the initial stages of cancer development. Antitumor effect of rhCypA in the CC-5 model was comparable to the action of 5-fluorouracil (5FU), and rhCypA administration prevented 5FU - induced leukopenia in the blood of tumor-bearing mice. In the LLC model, rhCypA injection before but not after tumor resection significantly suppressed the formation of post-surgical metastases. RhCypA exhibited no direct cytotoxic effects in vitro on human leukemia cells (K-562, HL-60, KG-1), indicating that rhCypA antitumor action could be mediated by its immunomodulating activity. In the B16 model, rhCypA had no impact on tumor angiogenesis and gene expression of several MMPs, endogenous CypA, and CD147, which play a crucial role in cancer progression. However, in this model, rhCypA stimulated gene expression of MMPs 8, 9, and 12 that could contribute to malignancy growth inhibition. Here, our findings pointed out CypA as one of the factors of antitumor host defense that can effectively control the initial stages of tumor and metastases formation by regulating the action of MMPs and changing the tumor microenvironment.

The peripheral T-cell pool consists of several, functionally distinct populations of CD8+ T cells. CD44 and CD62L are among the major surface markers that allow us to define T-cell populations. The expression of these molecules depends on the functional status of a T lymphocyte. Under lymphopenic conditions, peripheral T cells undergo homeostatic proliferation and acquire the memory-like surface phenotype CD44hiCD62Lhi. However, the data on the functional activity of these cells remains controversial. In this paper, we analyzed the effects of the adoptive transfer of syngeneic splenocytes on the recovery of CD8+ T cells in sublethally irradiated mice. Our data demonstrate that under lymphopenia, donor lymphocytes form a population of memory-like CD8+ T cells with the phenotype CD122+CD5+CD49dhiCXCR3+ that shares the phenotypic characteristics of true memory cells and suppressive CD8+ T cells. Ex vivo experiments showed that after adoptive transfer in irradiated mice, T cells lacked the functions of true effector or memory cells; the allogeneic immune response and immune response to pathogens were greatly suppressed in these mice.