Agents and methods to elicit anti-tumor immune response
Inventors
Gu, Hua • Hodes, Richard • Chiang, Jeffrey J. • Jang, Ihnkyung
Assignees
Columbia University in the City of New York • US Department of Health and Human Services
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Publication Number
US-9334522-B2
Publication Date
2016-05-10
Expiration Date
2027-09-13
Abstract
The invention provides an isolated, purified population of human cells comprising CD8+ T cells with reduced Cbl-b activity. The invention provides uses of such cells in methods for inducing or enhancing an anti-tumor immune response in a subject. These methods comprise: (a) providing a cell population, from a subject or from another source, which comprises CD8+ T cells, (b) reducing Cbl-b activity in the CD8+ T-cells, (c) administering the cells of step (b) to the subject. The invention provides methods for making CD8+ T cells that do not require stimulation through a co-receptor in order for the cell to become activated or proliferated in response to contact via its T cell receptor. Such methods are based upon reducing function of Cbl-b. The invention also provides methods for identifying agents which affect Cbl-b expression or activity.
Core Innovation
The invention provides isolated, purified populations of human CD8+ T cells with reduced Cbl-b activity, which do not require stimulation through a co-receptor to become activated or proliferate upon contact via their T cell receptor (TCR). Methods are described for making such CD8+ T cells by reducing or eliminating Cbl-b function or expression, including knockdown by siRNA or knockout of the gene. These modified CD8+ T cells can stimulate or enhance an anti-tumor immune response upon administration to a subject, including subjects suffering from tumors.
The need addressed arises from the background that most antigenic tumors are not rejected despite the presence of tumor-infiltrating cytotoxic T lymphocytes (CTLs) due to mechanisms such as low tumor immunogenicity, lack of co-stimulatory ligands like B7 on tumor cells, active suppression by tumor-derived factors like TGF-beta, and immunoregulatory host mechanisms. Tumor-specific CTLs often require two signals—TCR engagement and co-stimulation via receptors like CD28—for full activation; absence of the latter results in T cell anergy and failure of tumor rejection. Existing methods of enforcing co-stimulatory ligand expression on tumors or using dendritic cells for antigen presentation have limitations in eliciting efficient anti-tumor responses.
The core innovation proposes methods to render CD8+ T cells independent of co-stimulation by reducing Cbl-b activity, thereby enabling these so-called “super killer” T cells to be activated solely by TCR engagement. These Cbl-b-deficient CD8+ T cells are shown to produce substantial cytokines, resist suppression by TGF-beta, infiltrate tumors extensively, and mediate tumor rejection in vivo, including eradication of established tumors upon adoptive transfer. Methods also include identifying agents that inhibit Cbl-b expression or activity and using them therapeutically to induce anti-tumor immune responses without co-administration of vaccines or cytokines.
Claims Coverage
The patent includes ten main inventive features based on independent claims, focusing on methods for making co-stimulation-independent CD8+ T cells, inducing anti-tumor immune responses via reduced Cbl-b activity, methods of administration, and techniques for reducing Cbl-b activity.
Method for creating CD8+ T cells independent of co-stimulation
A method comprising providing CD8+ T cells and reducing Cbl-b activity in these cells to generate CD8+ T cells that do not require co-stimulation for activation and proliferation.
Method for inducing an anti-tumor immune response by administering modified CD8+ T cells
A method including providing CD8+ T cells, reducing their Cbl-b activity, and administering these cells to a subject to induce an anti-tumor immune response.
Sources of CD8+ T cells for modification
CD8+ T cells used for reduction of Cbl-b activity can be obtained from peripheral blood, lymph organs, or tumor infiltrates of subjects.
Inducing anti-tumor immune response with subject-derived CD8+ T cells
Isolating CD8+ T cells from the subject, reducing Cbl-b activity in these cells, and administering them back to the same subject.
Stimulating proliferation of modified CD8+ T cells after Cbl-b reduction
Following Cbl-b activity reduction, CD8+ T cells can be stimulated to proliferate, including by anti-CD3 antibody and/or IL-2 exposure.
Increasing tumor-specific CD8+ T cells by stimulation with tumor cells
Mixing the CD8+ T cells with tumor cells isolated from the subject to increase numbers of tumor-specific CD8+ T cells.
Further stimulation of tumor-specific CD8+ T cells
Contacting tumor-specific CD8+ T cells with anti-CD3 antibody or IL-2, separately or combined, to further expand these cells.
Use of siRNA to reduce Cbl-b activity
Reducing Cbl-b activity by introducing siRNA targeting Cbl-b into CD8+ T cells, specifically including siRNA of SEQ ID NO: 1.
Treatment of specific tumor types
The subject in methods may suffer from melanoma, lymphoma, or solid tumors expressing MHC-I with antigens recognizable by CTLs.
Use of specific siRNA sequence for Cbl-b inhibition
Use of siRNA having the nucleotide sequence 5′-CAGGAGTATGAGACAGAAG-3′ (SEQ ID NO: 1) to reduce Cbl-b activity in CD8+ T cells.
The claims cover methods for producing CD8+ T cells independent of co-stimulation by reducing Cbl-b activity, administering these cells to induce anti-tumor immune responses, approaches for stimulating proliferation and specificity, and employing siRNA sequences to achieve Cbl-b reduction, including treatment of various tumor types.
Stated Advantages
Cbl-b−/− CD8+ T cells function independent of CD28 co-stimulation and CD4+ T cell help, allowing activation by TCR alone.
Such CD8+ T cells exhibit resistance to TGF-beta suppression, overcoming tumor-mediated immune suppression.
Adoptive transfer of Cbl-b deficient CD8+ T cells can effectively eradicate established tumors, including strong and weak antigenic tumors.
Ablation of Cbl-b enhances tumor infiltration by CD8+ T cells, improving immune surveillance and tumor rejection.
Use of Cbl-b modulation may avoid the need for exogenous cytokines or vaccines to boost costimulatory signaling.
Reduction of spontaneous tumors in ATM−/− mice demonstrates potential tumor-preventive effects by systemic Cbl-b inhibition.
Documented Applications
Use of CD8+ T cells with reduced Cbl-b activity to induce or enhance anti-tumor immune responses in subjects suffering from tumors.
Cancer immunotherapy including adoptive transfer of Cbl-b deficient CD8+ T cells derived from peripheral blood, lymph organs, or tumor infiltrates.
Treatment of specific tumor types such as melanoma, lymphoma, and solid tumors expressing MHC-I with CTL-recognizable antigens.
Generation of 'super killer' CD8+ T cells for therapeutic use by reducing Cbl-b activity via siRNA or gene knockout.
Screening and identification of agents that modulate Cbl-b activity for possible therapeutic use.
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