Publication Date:
2012-03-27
Description:
The immunostimulatory cytokine interleukin-2 (IL-2) is a growth factor for a wide range of leukocytes, including T cells and natural killer (NK) cells. Considerable effort has been invested in using IL-2 as a therapeutic agent for a variety of immune disorders ranging from AIDS to cancer. However, adverse effects have limited its use in the clinic. On activated T cells, IL-2 signals through a quaternary 'high affinity' receptor complex consisting of IL-2, IL-2Ralpha (termed CD25), IL-2Rbeta and IL-2Rgamma. Naive T cells express only a low density of IL-2Rbeta and IL-2Rgamma, and are therefore relatively insensitive to IL-2, but acquire sensitivity after CD25 expression, which captures the cytokine and presents it to IL-2Rbeta and IL-2Rgamma. Here, using in vitro evolution, we eliminated the functional requirement of IL-2 for CD25 expression by engineering an IL-2 'superkine' (also called super-2) with increased binding affinity for IL-2Rbeta. Crystal structures of the IL-2 superkine in free and receptor-bound forms showed that the evolved mutations are principally in the core of the cytokine, and molecular dynamics simulations indicated that the evolved mutations stabilized IL-2, reducing the flexibility of a helix in the IL-2Rbeta binding site, into an optimized receptor-binding conformation resembling that when bound to CD25. The evolved mutations in the IL-2 superkine recapitulated the functional role of CD25 by eliciting potent phosphorylation of STAT5 and vigorous proliferation of T cells irrespective of CD25 expression. Compared to IL-2, the IL-2 superkine induced superior expansion of cytotoxic T cells, leading to improved antitumour responses in vivo, and elicited proportionally less expansion of T regulatory cells and reduced pulmonary oedema. Collectively, we show that in vitro evolution has mimicked the functional role of CD25 in enhancing IL-2 potency and regulating target cell specificity, which has implications for immunotherapy.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3338870/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3338870/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Levin, Aron M -- Bates, Darren L -- Ring, Aaron M -- Krieg, Carsten -- Lin, Jack T -- Su, Leon -- Moraga, Ignacio -- Raeber, Miro E -- Bowman, Gregory R -- Novick, Paul -- Pande, Vijay S -- Fathman, C Garrison -- Boyman, Onur -- Garcia, K Christopher -- AR050942/AR/NIAMS NIH HHS/ -- GM07365/GM/NIGMS NIH HHS/ -- R01 AI051321/AI/NIAID NIH HHS/ -- R01 AI051321-05/AI/NIAID NIH HHS/ -- R01 CA065237/CA/NCI NIH HHS/ -- R01-GM062868/GM/NIGMS NIH HHS/ -- R01AI51321/AI/NIAID NIH HHS/ -- R37 AI051321/AI/NIAID NIH HHS/ -- T32 AI007290/AI/NIAID NIH HHS/ -- U01 DK078123/DK/NIDDK NIH HHS/ -- U19 AI 082719/AI/NIAID NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2012 Mar 25;484(7395):529-33. doi: 10.1038/nature10975.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22446627" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Binding Sites
;
Cell Line
;
Cell Proliferation
;
Crystallography, X-Ray
;
*Directed Molecular Evolution
;
Humans
;
Immunotherapy
;
Interleukin-2/*chemistry/genetics/*immunology/pharmacology
;
Interleukin-2 Receptor alpha Subunit/chemistry/deficiency/immunology/metabolism
;
Interleukin-2 Receptor beta Subunit/chemistry/metabolism
;
Killer Cells, Natural/immunology
;
Mice
;
Mice, Inbred C57BL
;
Models, Molecular
;
Molecular Dynamics Simulation
;
Mutant Proteins/*chemistry/genetics/*immunology/pharmacology
;
Mutation
;
Neoplasm Transplantation
;
Neoplasms/drug therapy/immunology
;
Phosphorylation
;
Protein Conformation
;
*Protein Engineering
;
STAT5 Transcription Factor/metabolism
;
Surface Plasmon Resonance
;
T-Lymphocytes/cytology/immunology
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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