Abstract
Apolipoprotein A-I (Apo A-I) is a major component of high density lipoproteins (HDL) that transport cholesterol in circulation. We have constructed an expression plasmid encoding a chimeric molecule encompassing interleukin-15 (IL-15) and Apo A-I (pApo-hIL15) that was tested by hydrodynamic injections into mice and was co-administered with a plasmid encoding the sushi domain of IL-15Rα (pSushi) in order to enhance IL-15 trans-presentation and thereby bioactivity. The pharmacokinetics of the Apo A-I chimeric protein were much longer than non-stabilized IL-15 and its bioactivity was enhanced in combination with IL-15Rα Sushi. Importantly, the APO-IL-15 fusion protein was incorporated in part into circulating HDL. Liver gene transfer of these constructs increased NK and memory-phenotype CD8 lymphocyte numbers in peripheral blood, spleen and liver as a result of proliferation documented by CFSE dilution and BrdU incorporation. Moreover, the gene transfer procedure partly rescued the NK and memory T-cell deficiency observed in IL-15Rα(-/-) mice. pApo-hIL15+ pSushi gene transfer to the liver showed a modest therapeutic activity against subcutaneously transplanted MC38 colon carcinoma tumors, that was more evident when tumors were set up as liver metastases. The improved pharmacokinetic profile and the strong biological activity of APO-IL-15 fusion protein holds promise for further development in combination with other immunotherapies.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apolipoprotein A-I / blood
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Blotting, Western
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CD8-Positive T-Lymphocytes / immunology
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Cell Count
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Cell Line, Tumor
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Cell Proliferation
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Gene Transfer Techniques*
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Genetic Therapy*
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Humans
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Immunologic Memory
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Immunotherapy*
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Injections, Subcutaneous
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Interleukin-15 / blood
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Interleukin-15 / genetics*
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Interleukin-15 / therapeutic use*
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Interleukin-15 Receptor alpha Subunit / chemistry
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Interleukin-15 Receptor alpha Subunit / metabolism
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Killer Cells, Natural / immunology
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Lipoproteins, HDL / blood*
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Liver / metabolism*
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Mice
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Mice, Inbred C57BL
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Neoplasm Metastasis
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Phenotype
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Protein Structure, Tertiary
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Recombinant Proteins / genetics
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Recombinant Proteins / therapeutic use
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Spleen / metabolism
Substances
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Apolipoprotein A-I
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Interleukin-15
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Interleukin-15 Receptor alpha Subunit
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Lipoproteins, HDL
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Recombinant Proteins
Grants and funding
MCO receives a Sara Borrell contract from Ministerio de Ciencia e Innovación. CA is supported by Fundación Científica of AECC. SH-S receives a Ramon y Cajal contract from Ministerio de Educación y Ciencia, and AM-K a scholarship from Ministerio de Ciencia e Innovación. PB a Miguel Servet contract from Fondo de Investigación Sanitaria (FIS); AP, JF and JM a scholarship from FIS. Financial support was from MEC/El Ministerio de Ciencia e Innovación (SAF2005-03131 and SAF2008-03294), RETIC (RD06/0020/0065), (PI060932 and FIS PI10/00264), European commission 7th famework program and SUDOE-IMMUNONET, Fundacion Mutua Madrileña, and “UTE for project FIMA”. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.