Characterization of Risk Factors for Modeling of Type 2 Diabetes Mellitus Induced by a High-Fat Diet in C57BL/6 Mice.

Type 2 diabetes mellitus develops due to a combination of genetic and environmental factors. C57BL/6 mice prone to obesity and leptin resistance were kept on a high-fat diet for 21 weeks. The animals showed a significant increase in fasting and postprandial glucose levels and body weight, the development of insulin resistance, and by week 18, an increase in the serum TNFα level. Metformin therapy at a dose of 250 mg/kg was effective against the background of disturbances in carbohydrate metabolism: animals showed a significant decrease in insulin resistance and TNFα level.

Taxifolin Reduces Blood Pressure in Elderly Hypertensive Male Wistar Rats.

Male Wistar rats aged 10 months were assigned to groups according to the initial level of systolic BP: hypertensive (systolic BP >115 mm Hg) and normotensive (systolic BP <115 mm Hg). The animals were injected intraperitoneally with 100 µg/kg taxifolin daily for 7 days. Systolic BP and HR were measured on the next day after single taxifolin administration and on the next day after 7-day injection course. In the group of hypertensive animals, systolic BP markedly decreased on the next day after the first injection; this decrease became even more pronounced (to the level of normotensive animals) at the end of the taxifolin course. In the group of normotensive animals, systolic BP remained unchanged. Hence, we demonstrate the possibility of course administration of taxifolin for BP normalization in hypertensive patients.

Comparison of Biochemical Parameters and Pathomorphological Changes in Rats Receiving Standard and High-Fat Diets during Modeling of Streptozotocin Diabetes.

The use of a high-fat diet, along with streptozotocin administration, can provide more profound insight into the mechanism of development of complications in diabetes, as well as their treatment. High-fat diet given over 3 weeks before intraperitoneal injection of streptozotocin in a dose of 40 mg/kg promoted the appearance of hyperglycemia in Wistar rats. The biochemical analysis of blood serum revealed increased levels of urea, triglycerides, cholesterol, AST, ALT, and concentration of inorganic phosphates and K+ ions in the high-fat diet group in comparison with the control. Both the biochemical analysis of the blood and histological analysis showed more pronounced abnormalities in rats receiving high-fat diet in comparison with animals receiving standard ration. These changes are the early markers for the development of nephropathy, impaired liver function, and microvascular disorders typical of patients with diabetes mellitus.

Effect of Standard and High-Fat Diets during Modeling of Streptozotocin-Induced Diabetes in Rats on the Development of Complications.

For evaluation of the effect of high-fat diet on the development of diabetic complications, the rats were maintained on standard or high-fat diet. In 3 weeks, diabetes mellitus was modeled by single intraperitoneal injection of streptozotocin. Changes in hematological parameters, physical and biochemical parameters of the urine, and in the development of thermal allodynia were different after 15-week standard and high-fat diets.

[Criteria for the effectiveness of interleukin-2 immunotherapy in a spontaneous murine mammary tumor model].

A novel approach is suggested to identify more homogenous subgroups involved in the follow-up of growth of spontaneous mammary tumors in mice (116, history-based analysis). That depends on subclinical period (preneoplastic and non-invasive stages of tumor growth) as well as rate of growth after clinical manifestation. An analysis of tumor growth rate versus survival of experimental and control animals after primary diagnosis and clinical manifestation of tumor showed that following a single peritumoral 2.5 x 10(6) IU IL-2 treatment tumor growth slowed down (n = 29; p < or = 0.05) while survival tended to improve. Originally fast-growing tumors without significant subclinical stage continued to grow but slowly. Females with such tumors survived longer than untreated controls without showing, however, any improvement on that parameter.

[In vitro cell adhesion and integrin expression by calcium ionophore-treated mononuclear cells from patients with acute myeloid leukemia]. / Adgezivnye svoistva i ékspressiia integrinov kletkami bol'nykh ostrymi mieloidnymi leikozami, stimulivannymi v kul'ture ionoforom dlia ionov kal'tsiia.

As shown elsewhere, cultured acute myeloid leukaemia blasts acquire certain characteristics of dendritic cells upon stimulation with cytokines and calcium ionophore. The ability of leukaemia-derived dendritic-like cells to express immune costimulatory molecules and dendritic cell marker CD83 has been extensively investigated. Although migratory capacity is a major attribute of dendritic cells, the ability of in vitro modified blasts for adhesion, chemotaxis and homing remain elusive. In the present paper, we show that after stimulation with calcium ionophore acute myeloid leukaemia blasts as well as normal dendritic cell precursors demonstrate increased capacity of binding fibronectin and denatured collagen. The expression pattern of integrins on dendritic-like leukaemic cells in general closely resembles that of monocyte-derived dendritic cells, however, variation in cell properties isolated from blood of individual patients are observed.

The CD68 protein as a potential target for leukaemia-reactive CTL.

CD68, a haematopoietic differentiation marker of the monocyte-macrophage lineage, is expressed in various human malignancies including chronic and acute myeloid leukaemia (AML). While the majority of normal CD34(+) cells are negative for CD68 expression, CD34(+) cells from AML patients produce elevated amounts of this protein. The purpose of this study was to identify CTL epitopes in the human CD68 protein. Mouse CD68 was also analysed to search for epitopes that could be used in murine tumor model. Peptides binding to murine H2(b) class I molecules were identified and used to stimulate CTL responses from allogeneic donor mice to avoid immunological tolerance. High avidity CTL clones specific for three different peptide epitopes did not kill CD68-expressing murine target cells, indicating that endogenous antigen processing failed to produce sufficient amounts of these peptides. In contrast, allo-restricted human CTL specific for an HLA-A2-binding peptide of CD68 recognised not only picomolar concentrations of peptide, but also displayed low levels of killing against HLA-A2-positive K562 and THP-1 leukemia cell lines and blast cells from AML patients. These data suggest that human leukaemia cells express limited amounts of CD68-derived peptides, and that high avidity CTL capable of recognising sub-picomolar concentrations of peptides are required for efficient killing of leukaemia cells.

Circumventing tolerance to a human MDM2-derived tumor antigen by TCR gene transfer.

We identified a tumor-associated cytotoxic T lymphocyte (CTL) epitope derived from the widely expressed human MDM2 oncoprotein and were able to bypass self-tolerance to this tumor antigen in HLA-A*0201 (A2.1) transgenic mice and by generating A2.1-negative, allo-A2.1-restricted human T lymphocytes. A broad range of malignant, as opposed to nontransformed cells, were killed by high-avidity transgenic mouse and allogeneic human CTLs specific for the A2.1-presented MDM2 epitope. Whereas the self-A2.1-restricted human T cell repertoire gave rise only to low-avidity CTLs unable to recognize the natural MDM2 peptide, human A2.1+ T lymphocytes were turned into efficient MDM2-specific CTLs upon expression of wild-type and partially humanized high-affinity T cell antigen receptor (TCR) genes derived from the transgenic mice. These results demonstrate that TCR gene transfer can be used to circumvent self-tolerance of autologous T lymphocytes to universal tumor antigens and thus provide the basis for a TCR gene transfer-based broad-spectrum immunotherapy of malignant disease.

[Induction of co-stimulatory molecules on the surface of blast cells in patients with acute myeloid leukemia]. / Induktsiia kostimuliatornykh molekul na poverkhnosti blastnykh kletok u bol'nykh ostrymi mieloidnymi leikozami.

AIM: To compare the capacity of ionophore for calcium ions and growth factors (granulocytic-macrophagal colony-stimulating factor, interleukin-4, tumor necrosis factor) to induce costimulatory molecules on the surface of blast cells from patients with acute myeloid leukemia (AML). MATERIALS AND METHODS: The study was carried out in 6 patients with primary and resistant AML using culturing and flow cytometry. RESULTS: Blast cells obtained from patients during diagnosis of AML and after drug therapy of resistant AML acquire the dendrite phenotype under the effects of growth factors and Ca ion ionophore. CONCLUSION: Calcium metabolism modulators can be used for creation of antileukemic vaccines.

[The induction of the antitumor activity of T-lymphocytes by antigen-presenting cells obtained from the blast cells of patients with acute leukemias]. / Induktsiia protivoopukholevoi aktivnosti T-limfotsitov antigenprezentiruiushchimi kletkami, poluchennymi iz blastnykh kletok bol'nykh ostrymi leikozami.

AIM: To produce antigen-presenting cells (APC) from tumor cells of patients with acute leukemia and to induce autologous cytotoxic tumor-specific T-lymphocytes in vivo and in vitro. MATERIAL AND METHODS: Culture examinations, flow cytofluorometry were made in 3 patients with acute myeloid leukemia (AML) and 1 patient with acute lymphoblastic leukemia (ALL). RESULTS: Culturing of blast cells in the presence of growth factors produced APC in 4 patients with acute leukemia. The use of fibronectin layer with added collagen proved most effective for the above production. In culture, APC induced autologous tumor-specific T-lymphocytes which selectively lysed tumor cells. Pilot clinical trial was made of dendritic cells suspension in a patient with resistant AML. CONCLUSION: A new perspective immunotherapy of acute leukemia is proposed.

Allo-major histocompatibility complex-restricted cytotoxic T lymphocytes engraft in bone marrow transplant recipients without causing graft-versus-host disease.

Previous experiments in humans and mice have shown that allogeneic donors can serve as a source of cytotoxic T lymphocytes (CTL) specific for proteins, such as cyclin-D1 and mdm-2, expressed at elevated levels in tumor cells. In vitro, allo-major histocompatibility complex (MHC)-restricted CTL against these proteins selectively killed allogeneic tumor cells, including lymphoma, but not normal control cells. This suggested that these CTL may be useful for adoptive tumor immunotherapy, provided that they (1) survive in MHC-disparate hosts, (2) maintain their killing specificity, and (3) do not attack normal host tissues. Here, we used cloned allo-restricted CTL isolated from BALB/c mice (H-2(d)) that killed H-2(b)-derived tumor cells expressing elevated levels of the mdm-2 target protein. When these CTL were injected into bone marrow transplanted (BMT) C57BL/6 (H-2(b)) recipients, they consistently engrafted and were detectable in lymphoid tissues and in the bone marrow (BM). Long-term survival was most efficient in spleen and lymph nodes, where CTL were found up to 14 weeks after injection. The administration of CTL did not cause graft-versus-host disease (GVHD) normally associated with injection of allogeneic T cells. These data show that allo-restricted CTL clones are promising reagents for antigen-specific immunotherapy in BMT hosts, because they engraft and retain their specific killing activity without causing GVHD.

Generation of human tumor-reactive cytotoxic T cells against peptides presented by non-self HLA class I molecules.

The cyclin-D1 protein, which was found to be overexpressed in various human tumors, promotes cell cycle progression from the G1 into the S phase. It is normally expressed at low levels in several tissues and is likely to induce immunological tolerance. We have recently shown in a murine system that T cell tolerance to a widely expressed protein was circumvented by raising cytotoxic T lymphocytes (CTL) from MHC-mismatched donors. In this study, we tested whether it is possible to raise human allo-restricted CTL against the cyclin-D1 protein. The human cell line T2 is deficient in the genes encoding the transporter associated with antigen processing (TAP), resulting in inefficient loading of HLA-A2 class I molecules with endogenous peptides. Thus, a large number of A2 molecules can bind exogenously supplied synthetic peptides. Peripheral blood mononuclear cells from HLA-A2-negative donors were stimulated with T2 cells presenting cyclin-D1-derived synthetic peptides. Cloning of bulk cultures revealed that a large proportion of CTL clones were peptide specific. One peptide induced CTL which lysed cyclin-D1-expressing breast cancer cells, but not control Epstein-Barr virus-transformed B lymphoid cells. The results show that HLA-A2-negative donors can be used to isolate tumor-reactive CTL specific for cyclin-D1 peptides presented by HLA-A2 class I molecules.

Long-term maintenance of hematopoiesis in irradiated mice by retrovirally transduced peripheral blood stem cells.

Mobilized peripheral blood stem cells (PBSC) are used as a source of hematopoietic stem cells for transplantation and gene therapy. It is still unclear, however, whether the PBSC are fully equivalent to normal bone marrow hematopoietic stem cells and whether they are able to provide long-term function of transgene in reconstituted mice. In the present study, mobilized PBSC from male mice were transduced with human adenosine desaminase gene (hADA) and were used for reconstitution of lethally irradiated female mice. At 1 1/2, 3, 6, 9, and 12 months after reconstitution, the bone marrow cells were repeatedly collected from each mouse under light anesthesia and the number of colony-forming unit-spleen (CFU-S), spleen repopulating ability (SRA), and the integration of human ADA gene were studied in CFU-S-derived colonies by polymerase chain reaction (PCR) and Southern blot hybridization analyses. After 9 months, the proportion of donor CFU-S detected by PCR with a Y-chromosome-specific probe in mice reconstituted with mobilized PBSC was 75.3% +/- 6.0%, which is similar to the concentration of donor CFU-S seen after bone marrow transplantation. Similarly, there was no difference in the concentration of CFU-S in mice reconstituted with transduced mobilized PBSC or bone marrow cells. However, in both cases the CFU-S content in the bone marrow was reduced fivefold to 10-fold compared with the concentration of CFU-S in mice transplanted with nontransduced bone marrow. The SRA of CFU-S in mice reconstituted with peripheral blood and bone marrow cells was the same 1.5 months posttransplantation, but after an additional 4 months, SRA of mice reconstituted with bone marrow cells was fivefold higher as compared with those engrafted by PBSC. The integration of the human ADA gene was observed during 9 months in about 60% of studied CFU-S. The proportion of marked colonies sharply decreased 1 year following reconstitution. One to 9 individually labeled clones could be shown simultaneously by Southern blot hybridization in the same reconstituted mice during the whole period of observation. The time of clone existence was about 3 months. We conclude that long-term marrow repopulating cells mobilized into circulation by treatment with granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) are capable of maintaining lifelong polyclonal hematopoiesis in reconstituted mice.

Peptide-specific cytotoxic T lymphocytes restricted by nonself major histocompatibility complex class I molecules: reagents for tumor immunotherapy.

Studies in melanoma patients have revealed that self proteins can function as targets for tumor-reactive cytotoxic T lymphocytes (CTL). One group of self proteins MAGE, BAGE, and GAGE are normally only expressed in testis and placenta, whilst another group of CTL recognized proteins are melanocyte-specific differentiation antigens. In this study we have investigated whether CTL can be raised against a ubiquitously expressed self protein, mdm-2, which is frequently overexpressed in tumors. The observation that T-cell tolerance is self major histocompatibility complex-restricted was exploited to generate CTL specific for an mdm-2 derived peptide presented by nonself major histocompatibility complex class I molecules. Thus, the allo-restricted T-cell repertoire of H-2d mice was used to isolate CTL specific for the mdm100 peptide presented by allogeneic H-2Kb class I molecules. In vitro, these CTL discriminated between transformed and normal cells, killing specifically Kb-positive melanoma and lymphoma tumors but not Kb-expressing dendritic cells. In vivo, the CTL showed antitumor activity and delayed the growth of melanoma as well as lymphoma tumors in H-2b recipient mice. These experiments show that it is possible to circumvent T-cell tolerance to ubiquitously expressed self antigens, and to target CTL responses against tumors expressing elevated levels of structurally unaltered proteins.

T cell epitopes in human papilloma virus proteins.

Infection by HPV is associated with several human diseases such as warts of the skin, condylomata of the genital track and carcinoma of the cervix. Although there is strong evidence for immune control of HPV types causing warts and condylomata, it is currently unclear whether patients infected with transforming HPV types can mount efficient T cell responses. Despite the apparent low immunogenicity of transforming HPV types, several Th and CTL epitopes have been identified in proteins derived from HPV16. This transforming virus is most frequently present in women with CIN and cervical carcinoma and knowledge of T cell recognisable proteins may eventually lead to the design of immune-stimulating anti-HPV16 vaccines.

Limitations of predictive motifs revealed by cytotoxic T lymphocyte epitope mapping of the human papilloma virus E7 protein.

Human papilloma virus (HPV) type 16 is found in the majority of cervical cancer patients and the transforming protein E7 is consistently expressed in cancer cells, making it a potential target for immune attack. In this study we have investigated whether E7 gains access to the MHC class I processing pathway and provides cytotoxic T lymphocyte (CTL) stimulating peptide epitopes. CTL were induced in H-2b mice by immunization with recombinant vaccinia virus expressing E7 (Vac-E7). To map CTL recognition, natural peptides were purified from cells expressing either intact or truncated E7 protein. Following peptide separation by HPLC one major CTL epitope was detected and truncated constructs localized this epitope to the C-terminal region. Mapping with synthetic peptides indicated that residues 49-57 (RAHYNIVTF) were recognised by anti-E7 CTL. Synthetic 49-57 peptide was used to induce CTL, which recognized the same HPLC purified natural peptide fractions as anti-E7 CTL. Binding motifs for H-2b class I molecules did not predict residues 49-57 to be a CTL epitope, but instead the sequence 21-28 (DLYCYEQL) which contains a Kb anchor motif. Synthetic 21-28 peptide was found to bind to Kb class I molecules and readily induced CTL, indicating that the T cell repertoire of H-2b mice can recognize this epitope. However, these CTL did not recognize peptides isolated from E7 expressing cells, showing that natural processing did not produce detectable levels of the 21-28 epitope. Together, the data demonstrate that an unexpected E7 peptide can function as a major CTL epitope.

Strategies for studying mouse and human immune responses to human papillomavirus type 16.

Cytotoxic T lymphocytes (CTL) are an important protective mechanism in viral infection and can be effective against tumours. We have investigated the tumour-associated E6 and E7 genes of human papillomavirus type 16 as CTL targets. In H-2b mice we have defined epitopes in E6 and E7 which can readily generate CTL in vivo and we have shown that HLA-A2.1 transgenic mice can generate an HLA-A2.1-restricted response. We have been unable to reveal a primed CTL response in humans. These paradoxical findings imply that human papillomavirus may fail to stimulate a systemic CTL response and/or employ strategies for evading or down-regulating such a response.