In:
Clinical Cancer Research, American Association for Cancer Research (AACR), Vol. 14, No. 2 ( 2008-01-15), p. 579-588
Abstract:
Purpose: To provide proper costimulation required for effective cancer T-cell immunity, Fc-GITRL fusion proteins were generated for use in immunotherapy protocols. Experimental Design: Soluble fusion proteins consisting of the Fc fragment of immunoglobulin and the murine glucocorticoid-induced tumor necrosis factor–related receptor ligand (mGITRL) connected with different linkers were genetically engineered and tested for their potency in two BALB/c solid tumor models. Results: In vivo, construct #178-14 (−5aa, −linker) showed the best activity ( & gt;90% tumor reduction) at doses ranging from 5 to 25 μg and was found to be intact by gel electrophoresis. Similar doses used with construct #175-2 (-linker) produced good but not as high tumor regression. Construct #5-1 (+linker), which was found to be relatively unstable by SDS gel electrophoresis, produced & lt;60% tumor regression and required a higher dose (100 μg) to produce optimal results. Survival curves showed that Fc-mGITRL treatment extended the life of 80% of tumor-bearing mice to & gt;3 months compared with controls that died by day 40. T-cell depletion studies showed that CD8+ T cells play a major role in Fc-mGITRL immunotherapy, and tumors removed from Fc-mGITRL– and DTA-1–treated mice showed a significant influx of granzyme B+ lymphocytes compared with controls. Finally, T regulatory (Treg) cell assays showed that, unlike other Fc fusion proteins, all three Fc-mGITRL constructs profoundly suppressed Treg activity. Conclusions: These studies suggest that a stable, intact Fc-mGITRL fusion protein can provide missing costimulation for the immunotherapy of solid tumors. In addition, Fc-mGITRL may alter Treg activity to enhance its effectiveness for tumor immunotherapy.
Type of Medium:
Online Resource
ISSN:
1078-0432
,
1557-3265
DOI:
10.1158/1078-0432.CCR-07-0940
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2008
detail.hit.zdb_id:
1225457-5
detail.hit.zdb_id:
2036787-9
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