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| 2. |
- Garkavij, Michael, et al.
(författare)
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Extracorporeal immunoadsorption from whole blood based on the avidin-biotin concept. Evaluation of a new method
- 1996
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 35:3, s. 309-312
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Tidskriftsartikel (refereegranskat)abstract
- This study of 36 rats with rat colon adenocarcinoma transplants was carried out to investigate the efficacy of a new method of whole blood immunoadsorption (WBIA) in removing biotinylated monoclonal antibodies (MAbs) directly from unseparated blood, in order to increase 'the tumor/normal-tissue uptake ratio', as compared with extracorporeal immunoadsorption (ECIA) of antibodies from plasma. Compared with the ECIA system, the overall volume of the WBIA system (comprising only a pump, an adsorption column, a drop-chamber and tubings) was less (3.6 vs. 6.2 ml), and procedure duration 2 h less. The 17 rats undergoing the WBIA procedure, started 12 h after i.v. injection of 4.0-4.5 MBq 125I-BR96-biotin, manifested neither hemolysis nor any other complication; no signs of organ edema were found at dissection; whole body and blood radioactivity values were reduced by 51% and 89.5%, respectively. The WBIA method was as effective as ECIA, but technically simpler, safer and more reliable.
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| 3. |
- Hedlund, G, et al.
(författare)
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Maximal interferon-gamma production and early synthesis of interleukin-2 by CD4+ CDw29- CD45R- p80- human T lymphocytes.
- 1989
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Ingår i: Immunology. - 0019-2805. ; 66:1, s. 49-53
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Tidskriftsartikel (refereegranskat)abstract
- Functionally distinct subsets within the T-helper (CD4+) cell population have been described in man, rat and mouse. We have shown previously that the CD4+ 45R- human lymphocytes are producers of IL-2 within 24 hr of polyclonal stimulation and are the major interferon (IFN) producers. The mAbs 4B4 (CDw29) and Leu 8 (p80) are here used together with Leu-18 (CD45R) to characterize the subpopulations of the CD4+ human lymphocytes in more detail. The majority of the CD45R+ cells were CDw29- and the majority of the CDw29+ cells were CD45R-. Most of the CD45R+ cells (78%) were also p80+. A significant number of cells (12%) were CDw29- CD45R-. The predominant subpopulations were defined to be CDw29- CD45R+ p80+ (31%), CDw29+ CD45R- p80- (24%) and CDW29+ CD45R- p80+ (18%). Within the CD4+ CD45R- subpopulation different subsets vary in their capacities to produce IFN and to produce IL-2 within 24 hr after activation. CD4+ CDw29- CD45R- p80- T lymphocytes produced the largest quantities of IFN and IL-2.
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| 4. |
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| 5. |
- Liu, Hua, et al.
(författare)
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Low dose Zebularine treatment enhances immunogenicity of tumor cells
- 2007
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Ingår i: Cancer Letters. - : Elsevier BV. - 1872-7980 .- 0304-3835. ; 257:1, s. 107-115
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Tidskriftsartikel (refereegranskat)abstract
- Strategy: We have investigated how alterations in gene expression induced by the demethylating drug Zebularine affect the immune response tumor cells elicit. The rational has been to treat syngeneic rat colon cancer cells with Zebularine at different concentrations and then use these cells to study gene expression of different genes involved in cancer immunogenicity. Gene expressions were monitored by semi-quantitative PCR and real-time PCR. Results: Intriguingly there was a large increase in the production of indoleamine 2,3-dioxygenase (IDO) after treatment with 100 mu M Zebularine as compared with untreated tumor cells, whereas treatment with 20 mu M Zebularine caused a significant decrease of the IDO production. After immunization with syngeneic tumor cells, spleen cells were isolated and restimulated in vitro with irradiated tumor cells. Immune reactivity was measured by proliferation, and production of interferon gamma and interleukinl0. The immunogenicity of tumor cells treated in vitro with a low dose of Zebularine increased, whereas it decreased after high dose exposure. The inhibition of immunogenicity by 100 mu M Zebularine was shown to be counteracted by the IDO inhibitor I methyl-tryptophan (1MT), confirming that this effect of Zebularine is mainly caused by IDO induction. Differences using Zebularine-treated or non-treated cells for in vitro restimulation were marginal. Conclusion: Low dose treatment with Zebularine (20 mu M) decreases the production of the immunosuppressive IDO from rat colon cancer cells and enhances their immunogenicity, whereas high dose Zebularine treatment (100 mu M) enhances the IDO production from the cancer cells and suppresses their immunogenicity. This immunosuppression should be considered when cancer is treated with Zebularine or drugs acting in a similar way. (C) 2007 Published by Elsevier Ireland Ltd.
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| 6. |
- Mårtensson, Linda, et al.
(författare)
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High-Dose Radioimmunotherapy Combined With Extracorporeal Depletion in a Syngeneic Rat Tumor Model
- 2010
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Ingår i: Cancer. - : Wiley. - 1097-0142 .- 0008-543X. ; 116:4, s. 1043-1052
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aim of the current study was to investigate the possibility of increasing the maximal tolerated dose (MTD) of a tumor-selective radiolabeled antibody when radioimmunotherapy (RIT) is combined with extracorporeal depletion of radioimmunoconjugates from the circulation. Furthermore, the authors evaluated whether this increase in dose improved the therapeutic effect on solid manifest tumors in an immunocompetent animal model. METHODS: Rats were injected with high activities/body weight of lutetium (Lu-177)- or yttrium (Y-90)-labeled antibody conjugates (monoclonal antibody tetraazacyclododecanetetraacetic acid-biotin) and subjected to removal of the conjugate from the circulation by extracorporeal affinity adsorption treatment 24 hours postinjection. Myelotoxicity was assessed by analysis of blood parameters for 12 weeks. The effect of increased doses in combination with extracorporeal affinity adsorption treatment was evaluated with respect to myelotoxicity and therapeutic effect in a syngeneic rat colon cancer model. RESULTS: The MTD of Lu-177- or Y-90-labeled immunoconjugates could be increased 2.0x or 1.5x, respectively, when RIT was combined with extracorporeal affinity adsorption treatment. All animals treated with Lu-177- or Y-90-labeled antibodies showed persistent complete response of manifest tumors (approximately 10 x 15 mm) within 16 days postinjection. However, several animals showed disseminated disease 1.5 to 3 months postinjection. CONCLUSIONS: Extracorporeal affinity adsorption treatment is a method that safely and efficiently reduces myelotoxicity associated with RIT. Extracorporeal affinity adsorption treatment allows increased administered activity without increased toxicity, with the aim of increasing the absorbed dose to the tumor. However, because tumor/normal tissue radiosensitivity ratios are more favorable in rodents, it is not possible to draw any conclusions concerning the therapeutic efficacy of increased administered activity in combination with extracorporeal affinity adsorption treatment in this study. Targeted RIT with beta-emitting radionuclides seems not to be effective in microscopic disease, because metastases developed at sites without previously known disease. (C) 2010 American Cancer Society.
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| 7. |
- Mårtensson, Linda, et al.
(författare)
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Improved tumor targeting and decreased normal tissue accumulation through extracorporeal affinity adsorption in a two-step pretargeting strategy
- 2007
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 13:18, s. 5572-5576
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Evaluation of the possibilities of reducing the accumulation of radiolabeled streptavidin in radiosensitive organs by extracorporeal affinity adsorption (ECAT). Experimental Design: Rats were injected with biotinylated antibody and subjected to removal of the antibodies from the circulation by ECAT 24 h after injection (avidin column). Animals were then injected with In-111-1,4,7,10-tetra-azacylododecane N,N',N '',N'''-tetraacetic acid (DOTA) streptavidin. In a third step, animals were subjected to a second ECAT 8 h after injection to remove the DOTA-streptavidin from the circulation (biotin column). Biodistribution and tumor targeting of DOTA-streptavidin 24 h after injection was determined. Results: Elimination of biotinylated antibody by ECAT before injection of DOTA-streptavidin increased the tumor targeting by 50%. In addition, the levels of DOTA-streptavidin in liver and lymph nodes were reduced by 60%, which implied a 4.3- and 3.8-fold increase of tumor-to-liver and tumor-to-lymph node ratios, respectively. By doing a second ECAT to remove DOTA-streptavidin from the circulation, accumulation in normal tissues was reduced. However, this latter ECAT also reduced tumor accumulation by 25% (mostly corresponding to radioactivity in the circulation). Conclusions: ECAT was efficient as a means of removing biotinylated antibodies and would probably also be efficient for the clearance of streptavidin-conjugated antibodies. Conversely, the use of ECAT for removal of radiolabeled streptavidin seems not to offer any advantage.
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| 8. |
- Nilsson, Rune, et al.
(författare)
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Different toxicity profiles for drug-versus radionuclide-conjugated BR96 monoclonal antibodies in a syngeneic rat colon carcinoma model
- 2011
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Ingår i: Acta Oncologica. - 1651-226X. ; 50:5, s. 711-718
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Tidskriftsartikel (refereegranskat)abstract
- Background. One of many approaches being evaluated in experimental models and in the clinic for the treatment of cancer is the use of antibodies conjugated to various drugs or radionuclides. The aim of the present study was to compare the toxicity profiles of radioimmunoconjugates and drug-immunoconjugates based on the same monoclonal antibody, evaluated in the same experimental model, that much resembles human studies. The pattern of dose-limiting toxicity of a monomethylauristatinconjugated monoclonal antibody (BR96) was compared to that of the same antibody conjugated with lutetium-177, and to the same non-conjugated antibody. Material and methods. Rats with established colon carcinoma were injected with monomethylauristatin-conjugated mAb-BR96, 177 Lu-BR96, or non-conjugated BR96. Liver, kidney, and myelotoxicity were assessed for 100 days by analysis of blood parameters. Body weight and therapeutic effects was also monitored. Results. Myelotoxicity was found to be dose limiting for the radionuclide BR96 conjugate. The dose-limiting factor was prolonged suppression of leukocytes (> 28 days) with increased risk of infections. For monomethylauristatin-conjugated BR96, liver toxicity was dose limiting, whereas no dose-limiting toxicity was observed with non-conjugated BR96. Both the drug-immunoconjugate and the radioimmunoconjugate resulted in decreased platelet counts, but the time to nadir and duration differed. Conclusion. The two conjugates resulted in different patterns of toxicity. By using the two conjugates of BR96 in a sequential therapeutic design it could be possible to increase the therapeutic window and hence probably the efficacy without significantly increasing the toxicity. This concept is regarded as valid regardless of conjugate or model chosen.
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| 9. |
- Nittby, Henrietta, et al.
(författare)
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Zebularine induces long-term survival of pancreatic islet allotransplants in streptozotocin treated diabetic rats.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- Coping with the immune rejection of allotransplants or autologous cells in patients with an active sensitization towards their autoantigens and autoimmunity presently necessitates life-long immune suppressive therapy acting on the immune system as a whole, which makes the patients vulnerable to infections and increases their risk of developing cancer. New technologies to induce antigen selective long-lasting immunosuppression or immune tolerance are therefore much needed.
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| 10. |
- Xue, Zhongtian, et al.
(författare)
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An epigenetic mechanism for high, synergistic expression of indoleamine 2,3-dioxygenase 1 (IDO1) by combined treatment with zebularine and IFN-γ: Potential therapeutic use in autoimmune diseases.
- 2012
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Ingår i: Molecular Immunology. - : Elsevier BV. - 1872-9142 .- 0161-5890. ; 51:2, s. 101-111
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Tidskriftsartikel (refereegranskat)abstract
- IDO1 can be induced by interferon gamma (IFN-γ) in multiple cell types. We have earlier described that the DNA methyltransferase inhibitor zebularine also induces IDO1 in several rat cell clones. We now describe a synergistic induction of IDO1 expression by IFN-γ and zebularine. To elucidate the mechanism of the IDO1 induction we have studied the methylation status in the promoter region of the IDO1 gene from both human monocytic THP-1 cells and H1D2 rat colon cancer cells. Interestingly, the IDO1 promoter is hypermethylated and IFN-γ is shown to induce a significant demethylation. The synergism in effect of zebularine and IFN-γ on IDO1 expression is paralleled by a similar synergistic effect on expression of two other IFN-γ-responsive genes, the transcription factors STAT1 and IRF1 with binding sites in the IDO1 promoter region. The demonstrated synergistic activation of IDO1 expression has implications in relation to therapeutic induction of immunosuppression in autoimmunity and chronic inflammation.
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