Priority Research Papers:
Surrogate in vitro activation of innate immunity synergizes with interleukin-7 to unleash rapid antigen-driven outgrowth of CD4+ and CD8+ human peripheral blood T-cells naturally recognizing MUC1, HER2/neu and other tumor-associated antigens
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Latha B. Pathangey1,*, Dustin B. McCurry1,*, Sandra J. Gendler1,2,3, Ana L. Dominguez1, Jessica E. Gorman1, Girish Pathangey1, Laurie A. Mihalik3, Yushe Dang4, Mary L. Disis4 and Peter A. Cohen2,3
1 Department of Biochemistry and Molecular Biology, Mayo Clinic, Scottsdale, AZ, USA
2 Department of Immunology, Mayo Clinic, Scottsdale, AZ, USA
3 Department of Hematology and Oncology, Mayo Clinic, Scottsdale, AZ, USA
4 Tumor Vaccine Group, Center for Translational Medicine in Women’s Health, University of Washington, Seattle, WA, USA
* Shared first authorship
Peter A. Cohen, email:
Sandra J. Gendler, email:
Mary L. Disis, email:
Keywords: PBMC, TLR agonists, GM-CSF, IL-7, adoptive therapy, MUC1
Received: October 07, 2016 Accepted: November 23, 2016 Published: December 11, 2016
Effective adoptive immunotherapy has proved elusive for many types of human cancer, often due to difficulties achieving robust expansion of natural tumor-specific T-cells from peripheral blood. We hypothesized that antigen-driven T-cell expansion might best be triggered in vitro by acute activation of innate immunity to mimic a life-threatening infection. Unfractionated peripheral blood mononuclear cells (PBMC) were subjected to a two-step culture, first synchronizing their exposure to exogenous antigens with aggressive surrogate activation of innate immunity, followed by γ-chain cytokine-modulated T-cell hyperexpansion. Step 1 exposure to GM-CSF plus paired Toll-like receptor agonists (resiquimod and LPS), stimulated abundant IL-12 and IL-23 secretion, as well as upregulated co-stimulatory molecules and CD11c expression within the myeloid (CD33+) subpopulation. Added synthetic long peptides (>20aa) derived from widely expressed oncoproteins (MUC1, HER2/neu and CMVpp65), were reliably presented to CD4+ T-cells and cross-presented to CD8+ T-cells. Both presentation and cross-presentation demonstrated proteasomal and Sec61 dependence that could bypass the endoplasmic reticulum. Step 2 exposure to exogenous IL-7 or IL-7+IL-2 produced selective and sustained expansion of both CD4+ and CD8+ peptide-specific T-cells with a predominant interferon-γ-producing T1-type, as well as the antigen-specific ability to lyse tumor targets. Other γ-chain cytokines and/or combinations were initially proliferogenic, but followed by a contractile phase not observed with IL-7 or IL-7+IL-2. Regulatory T-cells were minimally propagated under these culture conditions. This mechanistically rational culture sequence, effective even for unvaccinated donors, enables rapid preparation of T-cells recognizing tumor-associated antigens expressed by the majority of human cancers, including pancreatic cancers, breast cancers and glioblastomas.
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