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J Bubeník

Publications and source records attributed to J Bubeník.

At least 19 recordsLinked to original sources
PubMed1999

Interleukin 2 gene therapy of residual disease in mice carrying tumours induced by HPV 16.

Experiments were designed to examine the efficacy of IL-2 gene therapy in a surgical minimal residual tumour disease, using moderately immunogenic MK16/1/IIIABC murine cells transformed by activated ras and HPV 16 E6/E7 oncogenes (MK16 cells). Previously we demonstrated that surgical minimal residual tumour disease (SMRTD) could be effectively cured when murine Mc12 sarcoma had been resected and the operated mice were treated with irradiated Mc12 sarcoma cells engineered to secrete IL-2. In this study we performed IL-2 gene therapy of MK16 carcinoma with two types of irradiated MK16-unrelated tumour cell vaccines. One type of vaccine was derived from MHC class I-matched Mc12 sarcoma cells engineered to secrete IL-2 and the other from MHC class I-discordant IL-2 producing plasmacytoma X63-m-IL-2. The vaccines did not share any tumour rejection antigen with the MK16 cells and served exclusively as a local source of IL-2 production. Both vaccines were capable of inhibiting MK16 tumours when administered peritumorally up to 15 days after MK16 tumour challenge. The irradiated MHC class I-matched and IL-2-producing Mc12 sarcoma vaccine was then selected for therapy of MK16 SMRTD. Whereas the recurrence rate in the operated MK16 carcinoma bearers was 80%, so that only 20% of mice were cured by surgery, approximately 65% of the MK16 carcinoma bearers were permanently protected when the surgery was followed by local administration of the IL-2-producing Mc12 sarcoma vaccine.

Animals↗
PubMed1998

Interleukin-2 gene therapy of surgical minimal residual tumour disease.

Our study was designed to examine the effects of IL-2 gene therapy in a surgical minimal residual tumour disease (SMRTD). Mice were inoculated s.c. with methylcholanthrene (MC)-induced MC12 sarcoma cells. When the tumours reached 8 to 12 mm in diameter, they were excised, either completely ("microscopic SMRTD") or incompletely ("macroscopic SMRTD"). On day 90 after surgery, the tumour recurrence rate in untreated mice with microscopic SMRTD was approximately 30%, whereas in those with macroscopic SMRTD it was 75%. After surgery, experimental mice were treated with 2 types of irradiated, IL-2 gene-modified, IL-2-producing tumour cell vaccine. One type of vaccine was derived from the MC12 sarcoma cells (MC12-1L2/IV-3); the other type was derived from an unrelated X63-Ag8.653 plasmacytoma (X63-m-IL-2). Both types of vaccine failed to cure the macroscopic SMRTD. Whereas the X63-m-IL-2 vaccine was also ineffective in the microscopic SMRTD, the MC12-IL2/IV-3 vaccine was capable of preventing growth in all but one mouse (1164) with microscopic SMRTD when administered 2 to 5 days after surgery. If the vaccination took place 2 days before surgery or later than 5 days after surgery, the therapeutic activity was lost. Vaccination with irradiated parental MC12 cells did not produce any significant benefit compared to the operated-only mice. The protective effect of the MC12-L2/IV-3 vaccine was specific and comparatively long-lasting. Vaccinated mice, which had rejected the MC12 tumour residuum, were capable of rejecting a second inoculum of the MC12 sarcoma cells injected on days 35 to 110 after surgery but succumbed to the growth of 2 other unrelated murine sarcomas carrying different tumour-rejection antigens.

Animals↗
PubMed1998

Irradiated IL-2 gene-modified plasmacytoma vaccines are more efficient than live vaccines.

The effect of irradiation on the therapeutic efficacy of IL-2 gene-modified plasmacytoma cells used as a vaccine in the immunotherapy of parental murine plasmacytoma X63-Ag8.653 was examined. Local administration of the IL-2-secreting plasmacytoma irradiated with a dose of 50 Gy inhibited i.p. plasmacytoma growth more effectively than the administration of non-irradiated, live cell vaccines. Whereas the vaccination with the live cell vaccine could substantially prolong the survival of the tumour-bearing mice but did not significantly induce tumour regressions, the irradiated vaccines could substantially increase the number of tumour-free animals. The irradiated vaccines produce higher amounts of IL-2 than the live cell vaccines both in vitro and in vivo. Depletion of CD4+ and CD8+ effector cells with monoclonal antibodies has significantly decreased the effect of the vaccination. It can be concluded that both, CD4+ and CD8+ T lymphocytes are required for effective IL-2 gene therapy of the X63-Ag8.653 plasmacytoma and that the higher effect of the irradiated vaccines is probably due to their higher IL-2 production.

Animals↗
PubMed1997

Use of cryopreserved lymphocytes for assessment of the immunological effects of interferon therapy in renal cell carcinoma patients.

Experiments were designed to assess whether cryopreserved PBL could be used to monitor the immunological effects of IFN-alpha therapy in renal cell carcinoma (RCC) patients. It was found that programmed freezing and thawing of peripheral blood lymphocytes (PBL) from normal blood donors did not substantially change lymphocyte subset proportions and that cryopreserved PBL were able to proliferate in response to IL-2. It was also possible to activate the cytolytic activity of frozen PBL, and the frozen leukocytes did not lose their ability to secrete IFN-gamma after PHA activation. We have used these findings to investigate the immunological effects of IFN-alpha therapy in RCC patients. Cryopreservation of PBL samples collected from various patients over a period of 9-14 months enabled us to compare the in vitro reactivity of PBL from individual RCC patients repeatedly and under standard conditions. It was found that IL-2 induced proliferative responses of PBL from IFN-alpha non-responders, collected prior to IFN-alpha therapy, were significantly decreased as compared to those from normal blood donors. The proliferative responses of PBL from IFN-alpha responders, collected prior to IFN-alpha therapy, did not substantially differ from normal controls. Culture of PBL from IFN-alpha responders for 3 days in IFN-alpha-containing medium increased their lytic activity towards RCC targets, whereas no such increase was observed with non-RCC targets or using PBL from IFN-alpha non-responders or PBL from normal-blood donors. Enzyme-linked immunospot (ELISPOT) assays performed with cryopreserved lymphocytes from IFN-alpha non-responding RCC patients, collected prior to IFN-alpha therapy, revealed a substantially decreased ability to secrete IFN-gamma, as compared to IFN-gamma secretion of PBL from IFN-alpha responders or normal blood donors.

Carcinoma, Renal Cell↗
PubMed1997

[Gene therapy of malignant tumors. Prospects of cytokine gene transfer vaccines].

Therapeutic strategies based on the insertion of cytokine genes into the genome of tumour cells, followed by vaccination with the resulting genetically modified, cytokine-producing cells, represent a new potential prospect for treatment of cancer patients. In this review, the concept of cytokine gene-modified cancer vaccines is discussed; the discussion in focused on the rationale, characterization, progress in the development, preclinical testing, and first clinical trials. An effort is made to analyse and integrate the results obtained in different experimental model systems to determine the needed approaches and directions for further research.

Cancer Vaccines↗
PubMed1997

Treatment of transplanted spontaneous rat T-cell leukaemia with local administration of recombinant murine interleukin-2.

Spontaneous rat CD4+CD8-T-cell leukaemia transplanted in syngeneic recipients served as an experimental model system for IL-2 therapy. As a source of IL-2, supernatants from in vitro cultured plasmacytoma cell line X63-m-IL2 secreting constitutively recombinant murine IL-2 were utilized. Administration of IL-2, s.c. to the vicinity of the tumour inoculum, suppressed tumour growth. The tumour-inhibitory IL-2 effects were time- and dose-dependent. When the treatment has started 10 days after the challenge with 10(4) leukaemia cells, IL-2 inhibitory effects on the lymphoma growth in situ were demonstrated by lower tumour weight combined with necrotic changes. No histological signs of lymphoma generalization were found in parenchymatous organs of IL-2-treated rats in contrast to the untreated controls. No histological or functional injuries to the kidneys due to IL-2 administration were found. The results of effector cell phenotyping demonstrated the kinetics of the CD4+/CD8+ ratio characterized by CD4+ T-cell depletion and resulting increase in the percentage of CD8+ PBL.

Animals↗
PubMed1997

Recombinant interleukin-2 acts as an adjuvant and helps to increase the efficacy of tumour vaccines.

To examine augmentation of the resistance-inducing effect of tumour vaccines with IL-2, we have used the cytokine produced by genetically modified somatic cells, and a conventional experimental model of TRA-expressing, MC-induced murine fibrosarcoma transplanted in histocompatible mice. We have found that the effect of s.c. immunization with irradiated tumour vaccines can be substantially enhanced by IL-2 injected repeatedly at the site of vaccination. To investigate the kinetics of local and systemic immunocyte populations during the course of immunization with vaccine plus IL-2, some of the vaccinated mice were sacrificed and their regional LNC and spleen cells were used for phenotypic analysis. It has been found that local (s.c.) administration of the irradiated tumour vaccine plus IL-2 was accompanied by an early depletion of CD4+ and CD8+ cells in regional lymph nodes followed by subsequent rebound lymphocytosis. The local reaction was followed by a systemic response in the spleen characterized with an increase in TCR alpha beta + CD4+ lymphocytes.

Animals↗
PubMed1997

CTLL assay: comparison of two methods for IL-2 determination.

Two different modifications of CTLL techniques for IL-2 detection, the routine 3II-thymidine incorporation assay and the colorimetric MTT method, were compared. The reproducible results of the studies of supernatants from in vitro propagated transfected cells were obtained. The employed methods appeared to be comparable and are used simultaneously in our co-operating laboratories for estimation of the levels of IL-2 secreted by the transfectants that are applied as the source of the cytokine in therapeutic experiments.

Animals↗
PubMed1995

Interleukin-2 gene therapy of residual EL-4 leukaemia potentiates the effect of cyclophosphamide pretreatment.

Experiments were designed to investigate a possible therapeutic role of interleukin-2 (IL-2) gene transfer in the model of murine (EL-4) leukaemia pretreated with cyclophosphamide. It has been found that i.p. pretreatment of the leukaemic mice with cyclophosphamide, followed by i.v. administration of irradiated cells, genetically engineered to produce IL-2 and used as a source of the cytokine (IR-IL-2 cells), cured a substantial percentage of the leukaemic mice. Neither treatment with cyclophosphamide nor administration of the IR-IL-2 cells alone had any significant therapeutic effect. Labelling of the EL-4 and IR-IL-2 cells with different fluorescent cell linkers followed by i.v. injection and detection of the labelled cells in cryostat sections of various organs has shown that both cell populations can be detected almost exclusively in the red pulp of the spleen, close to the white pulp nodules, thus providing the possibility of short-range local interactions among the IL-2-producing cells, IL-2-responsive defence effector cells and EL-4 leukaemia targets.

Animals↗
PubMed1995

[CT-guided pelvic osteosynthesis. Preliminary report on a new operative technic].

The authors proposed new method for surgical treatment of slightly dislocated fractures of the sacrum and acetabulum and also small traumatic dislocations in the sacroiliac joint. Cannulated screws were used for percutaneous osteosynthesis under guidance of computerised tomography. CT guided surgery enables to choose the correct direction and length of introduced screws with regard to the shape and localisation of the fracture. During the step by step procedure the reduction effect can be directly checked and the surgical strategy immediately modified. The advantages of this method are minimal invasiveness, high accuracy and possibility of rapid mobilisation of treated patient.

Adult↗
PubMed1994

Subcutaneous interleukin-2 in combination with vinblastine for metastatic renal cancer: cytolytic activity of peripheral blood lymphocytes.

Eight patients with progressive metastatic renal cell carcinoma were selected for one course of subcutaneous recombinant interleukin-2 (IL-2) plus vinblastine (VBL) treatment lasting for seven weeks. Seven of the eight patients were evaluable for response, eight for toxicity. Peripheral blood lymphocytes (PBL) from the evaluable patients were isolated and frozen prior to, during, and after the treatment courses; kinetics of their cytolytic activity was assessed and compared under standard conditions in 51Cr microcytotoxicity assay with natural killer (NK)-sensitive and NK-resistant human tumor targets. Among the evaluable patients treated, there was 1 partial responder (10+ months, regressions occurred in lung, retroperitoneal lymph nodes and adrenal metastases) and 3 patients achieved a stable disease (10+, 10+, 5+ months). Systemic toxicity was mild to moderate with treatment-limiting adverse effects in one patient (severe thrombocytopenia, grade IV). In the IL-2-treated patients, the cytolytic activity of PBL directed against NK-sensitive targets rapidly decreased during the first week of IL-2 treatment, approaching the negative values on day 10. Then the cytolytic activity was slowly increasing and reached its maximum within another two weeks. Afterwards, the cytolytic activity of PBL was again decreasing and the approximate values of the initial cytolysis were reached after 6-8 weeks. In contrast, with NK-resistant targets such characteristic kinetics of PBL cytolytic activity was not observed. The kinetics of PBL-mediated cytolysis was similar in IL-2-responders and non-responders, so that no correlation of in vivo and in vitro effects of subcutaneous IL-2 and VBL treatment could be established.

Aged↗
PubMed1994

Gene therapy of plasmacytoma: comparison of the therapeutic efficacy of tumour cells transduced with the interleukin-2, interleukin-4, or interleukin-6 genes.

The present study was designed to compare the tumour inhibitory effects of local therapy based on insertion of cloned IL-2, IL-4, or IL-6 genes into the genome of murine plasmacytoma X63-Ag8.653, followed by injection of the genetically modified cells to the vicinity of the parental plasmacytoma growing in syngeneic mice. It was also designed to investigate the effects of combined gene therapy with IL-2- and IL-6-producing plasmacytoma cells. It has been found that insertion of the IL-2 gene into the genome of X63-Ag8.653 cells can abrogate tumorigenicity of the transduced cells more effectively than insertion of the IL-4 or IL-6 gene. Peritumoral administration of the genetically modified plasmacytoma cells producing IL-6 (X63-h-IL-6) resulted in a therapeutic effect comparable with that of the IL-2-producing cells (X63-m-IL-2), whereas no substantial therapeutic effect of IL-4-producing cells (X63-m-IL4) was observed. The combined gene therapy with IL-2- and IL-6-producing cells did not give any additive or potentiated therapeutic effect.

Animals↗
PubMed1993

Utilization of interleukin-2 gene transfer in local immunotherapy of cancer.

It has been previously found that local administration of Balb/c plasmacytoma cells transformed and made non-tumorigenic by insertion of the cloned murine interleukin-2 (IL-2) gene induced regressions of a variety of murine tumours including the original Balb/c plasmacytoma X63-Ag8.653 growing in syngeneic mice. The tumour-inhibitory effect of the plasmacytoma cells transformed by IL-2 cDNA and designated as X63-m-IL-2 was due to their high constitutive production of IL-2. Here we show that admixture of syngeneic spleen cells to the X63-m-IL-2 transformants substantially (P < 0.025) increased the antitumour efficacy of the transformants. Balb/c spleen cells co-cultivated with X63-m-IL-2 cells in vitro yielded predominantly Thy 1.2+, CD3+, LFA-1+ lymphocytes, cytolytic for the X63-Ag8.653 plasmacytoma as well as for other murine tumours, including the X63-m-IL-2 target cells.

Animals↗