Biology subjects

Coburn, J.

Publications and source records attributed to Coburn, J..

3 recordsLinked to original sources

bioRxiv2025

Phenotypic and functional characterization of tumor-reactive T cells in malignant pleural effusions

BackgroundAdoptive cell therapy using tumor-infiltrating lymphocytes (TIL) is approved for the treatment of advanced melanoma but is limited by the need for patients to undergo surgical tumor resection. Malignant pleural effusions (MPE) may represent a more accessible source of tumor-reactive T cells. Here, we characterize the cellular composition as well as the transcriptional and functional properties of T cells from MPE compared with pulmonary metastasis and blood from a patient with melanoma. MethodsThe immune cellular composition was immunophenotyped by high-dimensional flow cytometry from synchronously collected MPE, a lung metastasis, and blood from a patient with metastatic melanoma. Sorted CD3+ T cells were profiled by single-cell RNA sequencing (scRNA-seq) and T cell receptor sequencing (scTCR-seq). TCR reactivity to autologous tumor was evaluated through in vitro activation assays with TCR-transduced Jurkat and autologous cancer cells. The killing capacity of ex vivo expanded T cells of autologous cancer cells was assessed through in vitro cytotoxicity assays. ResultsMPE had higher proportions of CD45+ immune cells and CD3+ T cells (70.5% vs 50%) compared with tumor and was enriched for effector CD8+ T cells, CCR7-CD45RA- effector memory CD4+ T cells, and quiescent CD25highCD127low regulatory CD4+ T cells. MPE T cells exhibited lower levels of co-inhibitory receptors (PD-1, LAG-3, TIGIT, TIM-3) expression relative to tumor. ScRNA-seq showed enrichment of NK-like effector CD8+ T cells in MPE. Pseudotime analysis indicated that MPE T cells were less exhausted than tumor T cells. The clonal repertoire of MPE and tumor highly overlapped, including 62.2% of predicted neoantigen-specific (NeoTCR) clonotypes. Notably, clonally-related NeoTCR T cells in MPE exhibited higher cytotoxic and stemness, and lower exhaustion signatures compared with sister clones in the tumor. Two of four selected NeoTCR clonotypes transduced in Jurkat cells demonstrated MHC class I-restricted reactivity in co-culture with autologous cancer cells. MPE T cells also readily expanded in the presence of high-dose IL-2 and demonstrated MHC class I-dependent killing of autologous cancer cells. ConclusionsMPE harbors polyclonal, tumor-reactive T cells with lower features of terminal exhaustion and higher cytotoxic potential relative to tumor T cells. MPE may therefore serve as a more accessible source for TIL therapy.

immunology↗

bioRxiv2025

cGAS-STING dependent type I IFN protects against Leptospira interrogans renal colonization in mice.

Leptospira interrogans is the major causative agent of leptospirosis. Humans, canines and livestock animals are susceptible to Leptospira species and can develop fulminant disease. Rodents serve as reservoir hosts in which the bacteria colonize the renal tubules and are excreted in the urine. The host immune response to Leptospira spp. remains poorly defined. We show that L. interrogans induces a robust type I interferon (IFN) response in human and murine macrophages that is dependent on the cytosolic dsDNA sensor Cyclic GMP-AMP Synthase (cGAS) and the Stimulator of IFN Genes (STING) signaling pathway. Further, we show that mice deficient in the IFN/{beta} receptor subunit 1 (IFNAR1) or STING had higher bacterial burdens and increased renal colonization following infection in vivo suggesting that cGAS-STING-driven type I IFN is required for the host defense against L. interrogans. These findings demonstrate the significance of cGAS-STING-dependent type I IFN signaling in mammalian innate immune responses to L. interrogans. Author SummaryLeptospirosis is a globally distributed zoonotic disease caused by spirochetes belonging to the genus Leptospira. While humans, livestock, and dogs can develop severe or even fatal illness upon infection, rodents typically serve as asymptomatic reservoir hosts. A defining feature of the leptospiral life cycle is the ability of the pathogen to colonize the kidney in these reservoir host species, leading to prolonged urinary shedding and environmental dissemination. Despite the significant global burden of leptospirosis, the innate immune pathways that detect this pathogen and prevent renal colonization remain poorly understood. In this study we demonstrate that L. interrogans induces a robust type I IFN cytokine response from macrophages. The induction of this type I IFN response is dependent on sensing cytosolic DNA by the cGAS-STING pathway. Using in vivo mouse models of L. interrogans infection we further show that activation of this pathway is required to control bacterial burdens and reduce long-term kidney colonization. This study is the first to demonstrate a critical role for cGAS-STING and type I IFN in controlling L. interrogans infection.

immunology↗

bioRxiv2024

P66 is a bacterial mimic of CD47 that binds the anti-phagocytic receptor SIRPα and facilitates macrophage evasion by Borrelia burgdorferi

Summary ParagraphInnate immunity, the first line of defense against pathogens, relies on efficient elimination of invading agents by phagocytes. In the co-evolution of host and pathogen, pathogens developed mechanisms to dampen and evade phagocytic clearance. Here, we report that bacterial pathogens can evade clearance by macrophages through mimicry at the mammalian anti-phagocytic "dont eat me" signaling axis between CD47 (ligand) and SIRP (receptor). We identified a protein, P66, on the surface of Borrelia burgdorferi that, like CD47, is necessary and sufficient to bind the macrophage receptor SIRP. Expression of the gene encoding the protein is required for bacteria to bind SIRP or a high-affinity CD47 reagent. Genetic deletion of p66 increases phagocytosis by macrophages. Blockade of P66 during infection promotes clearance of the bacteria. This study demonstrates that mimicry of the mammalian anti-phagocytic protein CD47 by B. burgdorferi inhibits macrophage-mediated bacterial clearance. Such a mechanism has broad implications for understanding of host-pathogen interactions and expands the function of the established innate immune checkpoint receptor SIRP. Moreover, this report reveals P66 as a novel therapeutic target in the treatment of Lyme Disease.

immunology↗