Biology subjects

Seijo, B.

Publications and source records attributed to Seijo, B..

4 recordsLinked to original sources

bioRxiv2023

Acidity-induced dysfunction of CD8+ T cells is characterized by impaired IL-2 responsiveness and perturbations to mTORC1 signaling and c-Myc levels

CD8+ T cells play a critical role in cancer control but a range of barriers in the tumor microenvironment, including low pH, can impair their function. Here, we demonstrate that acidity dampens T-cell expansion mainly due to impaired IL-2 responsiveness, blunts cytokine secretion upon re-activation, and lowers the cytolytic capacity of CD8+ T cells expressing weak affinity TCR. We further reveal and dissect defects in both mTORC1 activity and c-Myc accumulation at low pH, the latter of which is largely due to proteasome-mediated degradation. In addition, lower intracellular levels of glutamine, glutamate and aspartate as well as elevated proline were noted, with no apparent impact on mTORC1 or c-Myc. Overall, low pH disrupts diverse intracellular signaling pathways as well as nutrient uptake/processing by T cells and we conclude that unless intracellular pH can be restored, multiple interventions will be required to overcome acidity-induced dysfunction.

cell biology↗

bioRxiv2023

Combination of NY-ESO-1-TCR-T-cells coengineered to secrete SiRPalpha decoys with anti-tumor antibodies to augment macrophage phagocytosis

The adoptive transfer of T cell receptor (TCR)-engineered T cells (ACT) targeting the HLA-A2 restricted cancer-testis epitope NY-ESO-1157-165 (A2/NY) has yielded favorable clinical responses against a variety of cancers. Two promising approaches to improve ACT efficacy are TCR affinity-optimization and combinatorial treatment strategies to reprogram the tumor microenvironment (TME). By computational design, we previously developed a panel of affinity-enhanced A2/NY-TCRs. Here, we have demonstrated improved tumor control and engraftment by T cells gene-modified to express one such TCR comprising a single amino acid replacement in CDR3{beta} (A97L). To harness macrophages in the TME, we coengineered TCR-T cells to constitutively or inducibly secrete a high-affinity signal regulatory protein alpha (SiRP) decoy (CV1) to block the CD47 dont eat me signal. We demonstrated better control of tumor outgrowth by CV1-Fc coengineered TCR-T cells but in subcutaneous xenograft tumor models we observed depletion of both CV1-Fc and CV1 coengineered T cells. Importantly, CV1 coengineered T cells were not depleted by human macrophages in vitro. Moreover, Avelumab and Cetuximab enhanced macrophage-mediated phagocytosis in vitro in the presence of CV1, and augmented tumor control upon ACT. Taken together, our study indicates important clinical promise for harnessing macrophages by combining CV1 coengineered TCR-T cells with tumor-targeting monoclonal antibodies.

bioengineering↗

bioRxiv2023

Transcriptional reprogramming by IL-2 variant generates metabolically active stem-like T cells

Interleukin-2 receptor (IL-2R)-mediated intracellular signaling is a key regulator of T-cell fate decisions. While the potent signals generated by IL-2 engagement execute effector differentiation, elevated metabolic activities and rapid cellular expansion, IL-15 binding induces a stemness/memory phenotype and a quiescent metabolic state. Here, we demonstrate that weak but sustained signaling generated by a non-IL-2R-binding variant of IL-2 (IL-2v) drive proliferation/metabolic and stemness transcriptional programs, thereby reprogramming CD8+ T cells into a hybrid metabolically active stem-like state. We further show that IL-2v-induced T cells are capable of superior engraftment, persistence, and tumor control when utilized in adoptive cell therapy. Taken together, our study highlights the ability to fine-tune cytokine engagement of cognate receptors in order to generate therapeutically relevant T-cell states and further reveals the metabolic plasticity of the T-cell memory program.

systems biology↗

bioRxiv2022

Orthogonal Gene Engineering Enables CD8+ T Cells to Control Tumors through a Novel PD-1+ TOX-indifferent Synthetic Effector State

Adoptive immunotherapy offers opportunities to reprogram T cells and the tumor microenvironment. Orthogonal engineering of adoptively transferred T cells with an IL-2R{beta}{gamma}-binding IL-2 variant, PD1-decoy and IL-33 led to cell-autonomous T-cell expansion, T-cell engraftment and tumor control in immunocompetent hosts through reprogramming of both transferred and endogenous CD8+ cells. Tumor-infiltrating lymphocytes adopted a novel effector state characterized by TOX suppression and specific expression of multiple effector molecules, most prominently granzyme C. While the IL-2 variant promoted CD8+ T-cell stemness and persistence, and was associated with downregulation of TOX, the combination with IL-33 was necessary to trigger the novel polyfunctional effector state. Rational T-cell engineering without host lymphodepletion enables optimal reprogramming of adoptively transferred T cells as well as mobilization of endogenous immunity into new functional CD8+ states mediating tumor control.

immunology↗