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1.
J Immunol ; 199(8): 2680-2691, 2017 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-28887429

RESUMEN

Of interest to the etiology of demyelinating autoimmune disease is the potential to aberrantly activate CD4+ T cells due to cross-recognition of multiple self-epitopes such as has been suggested for myelin oligodendrocyte glycoprotein epitope 35-55 (MOG35-55) and neurofilament medium protein epitope 15-35 (NFM15-35). NFM15-35 is immunogenic in C57BL/6 mice but fails to induce demyelinating disease by polyclonal T cells despite having the same TCR contact residues as MOG35-55, a known encephalitogenic Ag. Despite reported cross-reactivity with MOG-specific T cells, the polyclonal response to NFM15-35 did not expand threshold numbers of MOG38-49 tetramer-positive T cells. Furthermore, NFM lacked functional synergy with MOG to promote experimental autoimmune encephalomyelitis because NFM-deficient synonymous with knockout mice developed an identical disease course to wild-type mice after challenge with MOG35-55 Single-cell analysis of encephalitogenic T cells using the peptide:MHC monomer-based two-dimensional micropipette adhesion frequency assay confirmed that NFM was not a critical Ag driving demyelinating disease because NFM18-30-specific T cells in the CNS were predominantly reactive to MOG38-49 The absence of NFM contribution to disease allowed mapping of the amino acids required for encephalitogenicity and expansion of high-affinity, MOG-specific T cells that defined the polyclonal response. Alterations of N-terminal residues outside of the NFM15-35 core nonamer promoted expansion of high-affinity, MOG38-49 tetramer-positive T cells and promoted consistent experimental autoimmune encephalomyelitis induction, unlike mice challenged with NFM15-35 Although NFM15-35 is immunogenic and cross-reactive with MOG at the polyclonal level, it fails to expand a threshold level of encephalitogenic, high-affinity MOG-specific T cells.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Reacciones Cruzadas , Encefalomielitis Autoinmune Experimental/inmunología , Esclerosis Múltiple/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Animales , Células Cultivadas , Mapeo Epitopo , Femenino , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Glicoproteína Mielina-Oligodendrócito/inmunología , Fragmentos de Péptidos/inmunología , Unión Proteica
2.
Proc Natl Acad Sci U S A ; 113(20): 5610-5, 2016 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-27140637

RESUMEN

T cells are triggered when the T-cell receptor (TCR) encounters its antigenic ligand, the peptide-major histocompatibility complex (pMHC), on the surface of antigen presenting cells (APCs). Because T cells are highly migratory and antigen recognition occurs at an intermembrane junction where the T cell physically contacts the APC, there are long-standing questions of whether T cells transmit defined forces to their TCR complex and whether chemomechanical coupling influences immune function. Here we develop DNA-based gold nanoparticle tension sensors to provide, to our knowledge, the first pN tension maps of individual TCR-pMHC complexes during T-cell activation. We show that naïve T cells harness cytoskeletal coupling to transmit 12-19 pN of force to their TCRs within seconds of ligand binding and preceding initial calcium signaling. CD8 coreceptor binding and lymphocyte-specific kinase signaling are required for antigen-mediated cell spreading and force generation. Lymphocyte function-associated antigen 1 (LFA-1) mediated adhesion modulates TCR-pMHC tension by intensifying its magnitude to values >19 pN and spatially reorganizes the location of TCR forces to the kinapse, the zone located at the trailing edge of migrating T cells, thus demonstrating chemomechanical crosstalk between TCR and LFA-1 receptor signaling. Finally, T cells display a dampened and poorly specific response to antigen agonists when TCR forces are chemically abolished or physically "filtered" to a level below ∼12 pN using mechanically labile DNA tethers. Therefore, we conclude that T cells tune TCR mechanics with pN resolution to create a checkpoint of agonist quality necessary for specific immune response.


Asunto(s)
ADN/administración & dosificación , Activación de Linfocitos , Mecanotransducción Celular , Nanopartículas del Metal/administración & dosificación , Receptores de Antígenos de Linfocitos T/fisiología , Fenómenos Biomecánicos , Antígenos CD8/fisiología , Calcio/metabolismo , Oro , Humanos , Molécula 1 de Adhesión Intercelular/fisiología , Antígeno-1 Asociado a Función de Linfocito/fisiología
3.
Nano Lett ; 16(7): 4552-9, 2016 07 13.
Artículo en Inglés | MEDLINE | ID: mdl-27192323

RESUMEN

Short-range communication between cells is required for the survival of multicellular organisms. One mechanism of chemical signaling between adjacent cells employs surface displayed ligands and receptors that only bind when two cells make physical contact. Ligand-receptor complexes that form at the cell-cell junction and physically bridge two cells likely experience mechanical forces. A fundamental challenge in this area pertains to mapping the mechanical forces experienced by ligand-receptor complexes within such a fluid intermembrane junction. Herein, we describe the development of ratiometric tension probes for direct imaging of receptor tension, clustering, and lateral transport within a model cell-cell junction. These probes employ two fluorescent reporters that quantify both the ligand density and the ligand tension and thus generate a tension signal independent of clustering. As a proof-of-concept, we applied the ratiometric tension probes to map the forces experienced by the T-cell receptor (TCR) during activation and showed the first direct evidence that the TCR-ligand complex experiences sustained pN forces within a fluid membrane junction. We envision that the ratiometric tension probes will be broadly useful for investigating mechanotransduction in juxtacrine signaling pathways.


Asunto(s)
Membrana Celular/fisiología , Mecanotransducción Celular , Receptores de Antígenos de Linfocitos T/química , Transducción de Señal , Animales , Colorantes Fluorescentes , Oro , Ácidos Nucleicos Inmovilizados , Ligandos , Nanopartículas del Metal , Ratones Transgénicos , Linfocitos T/citología
4.
J Immunol ; 193(2): 571-9, 2014 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-24943217

RESUMEN

Autoreactive T cells infiltrating the target organ can possess a broad TCR affinity range. However, the extent to which such biophysical parameters contribute to T cell pathogenic potential remains unclear. In this study, we selected eight InsB9-23-specific TCRs cloned from CD4(+) islet-infiltrating T cells that possessed a relatively broad range of TCR affinity to generate NOD TCR retrogenic mice. These TCRs exhibited a range of two-dimensional affinities (∼ 10(-4)-10(-3) µm(4)) that correlated with functional readouts and responsiveness to activation in vivo. Surprisingly, both higher and lower affinity TCRs could mediate potent insulitis and autoimmune diabetes, suggesting that TCR affinity does not exclusively dictate or correlate with diabetogenic potential. Both central and peripheral tolerance mechanisms selectively impinge on the diabetogenic potential of high-affinity TCRs, mitigating their pathogenicity. Thus, TCR affinity and multiple tolerance mechanisms converge to shape and broaden the diabetogenic T cell repertoire, potentially complicating efforts to induce broad, long-term tolerance.


Asunto(s)
Diabetes Mellitus Tipo 1/inmunología , Tolerancia Inmunológica/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Linfocitos T/inmunología , Traslado Adoptivo , Secuencia de Aminoácidos , Animales , Unión Competitiva/inmunología , Trasplante de Médula Ósea/métodos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Línea Celular , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Epítopos de Linfocito T/inmunología , Epítopos de Linfocito T/metabolismo , Femenino , Citometría de Flujo , Insulina/deficiencia , Insulina/genética , Insulina/inmunología , Interleucina-2/inmunología , Interleucina-2/metabolismo , Islotes Pancreáticos/inmunología , Islotes Pancreáticos/metabolismo , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Ratones Transgénicos , Datos de Secuencia Molecular , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Linfocitos T/metabolismo , Linfocitos T/trasplante
5.
J Immunother Cancer ; 12(8)2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39097413

RESUMEN

BACKGROUND: Davoceticept (ALPN-202) is an Fc fusion of a CD80 variant immunoglobulin domain designed to mediate programmed death-ligand 1 (PD-L1)-dependent CD28 co-stimulation while inhibiting the PD-L1 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) checkpoints. The safety and efficacy of davoceticept monotherapy and davoceticept and pembrolizumab combination therapy in adult patients with advanced solid tumors were explored in NEON-1 and NEON-2, respectively. METHODS: In NEON-1 (n=58), davoceticept 0.001-10 mg/kg was administered intravenous either once weekly (Q1W) or once every 3 weeks (Q3W). In NEON-2 (n=29), davoceticept was administered intravenously at 2 dose levels (0.1 or 0.3 mg/kg) Q1W or Q3W with pembrolizumab (400 mg once every 6 weeks). In both studies, primary endpoints included incidence of dose-limiting toxicities (DLT); type, incidence, and severity of adverse events (AEs) and laboratory abnormalities; and seriousness of AEs. Secondary endpoints included antitumor efficacy assessed using RECIST v1.1, pharmacokinetics, anti-drug antibodies, and pharmacodynamic biomarkers. RESULTS: The incidence of treatment-related AEs (TRAEs) and immune-related adverse events (irAEs) was 67% (39/58) and 36% (21/58) with davoceticept monotherapy, and 62% (18/29) and 31% (9/29) with davoceticept and pembrolizumab combination, respectively. The incidence of ≥grade (Gr)3 TRAEs and ≥Gr3 irAEs was 12% (7/58) and 5% (3/58) with davoceticept monotherapy, and 24% (7/29) and 10% (3/29) with davoceticept and pembrolizumab combination, respectively. One DLT of Gr3 immune-related gastritis occurred during davoceticept monotherapy 3 mg/kg Q3W. During davoceticept combination with pembrolizumab, two Gr5 cardiac DLTs occurred; one instance each of cardiogenic shock (0.3 mg/kg Q3W, choroidal melanoma metastatic to the liver) and immune-mediated myocarditis (0.1 mg/kg Q3W, microsatellite stable metastatic colorectal adenocarcinoma), prompting early termination of both studies. Across both studies, five patients with renal cell carcinoma (RCC) exhibited evidence of clinical benefit (two partial response, three stable disease). CONCLUSIONS: Davoceticept was generally well tolerated as monotherapy at intravenous doses up to 10 mg/kg. Evidence of clinical activity was observed with davoceticept monotherapy and davoceticept in combination with pembrolizumab, notably in RCC. However, two fatal cardiac events occurred with the combination of low-dose davoceticept and pembrolizumab. Future clinical investigation with davoceticept should not consider combination with programmed death-1-inhibitor anticancer mechanisms, until its safety profile is more fully elucidated. TRIAL REGISTRATION NUMBER: NEON-1 (NCT04186637) and NEON-2 (NCT04920383).


Asunto(s)
Anticuerpos Monoclonales Humanizados , Antígeno CTLA-4 , Neoplasias , Humanos , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Monoclonales Humanizados/farmacología , Masculino , Femenino , Neoplasias/tratamiento farmacológico , Persona de Mediana Edad , Anciano , Adulto , Antígeno CTLA-4/antagonistas & inhibidores , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Inhibidores de Puntos de Control Inmunológico/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/metabolismo , Anciano de 80 o más Años , Antígenos CD28
6.
JCI Insight ; 8(16)2023 08 22.
Artículo en Inglés | MEDLINE | ID: mdl-37432736

RESUMEN

BACKGROUNDLow-dose anti-thymocyte globulin (ATG) transiently preserves C-peptide and lowers HbA1c in individuals with recent-onset type 1 diabetes (T1D); however, the mechanisms of action and features of the response remain unclear. Here, we characterized the post hoc immunological outcomes of ATG administration and their potential use as biomarkers of metabolic response to therapy (i.e., improved preservation of endogenous insulin production).METHODSWe assessed gene and protein expression, targeted gene methylation, and cytokine concentrations in peripheral blood following treatment with ATG (n = 29), ATG plus granulocyte colony-stimulating factor (ATG/G-CSF, n = 28), or placebo (n = 31).RESULTSTreatment with low-dose ATG preserved regulatory T cells (Tregs), as measured by stable methylation of FOXP3 Treg-specific demethylation region (TSDR) and increased proportions of CD4+FOXP3+ Tregs (P < 0.001) identified by flow cytometry. While treatment effects were consistent across participants, not all maintained C-peptide. Responders exhibited a transient rise in IL-6, IP-10, and TNF-α (P < 0.05 for all) 2 weeks after treatment and a durable CD4+ exhaustion phenotype (increased PD-1+KLRG1+CD57- on CD4+ T cells [P = 0.011] and PD1+CD4+ Temra MFI [P < 0.001] at 12 weeks, following ATG and ATG/G-CSF, respectively). ATG nonresponders displayed higher proportions of senescent T cells (at baseline and after treatment) and increased methylation of EOMES (i.e., less expression of this exhaustion marker).CONCLUSIONAltogether in these exploratory analyses, Th1 inflammation-associated serum and CD4+ exhaustion transcript and cellular phenotyping profiles may be useful for identifying signatures of clinical response to ATG in T1D.TRIAL REGISTRATIONClinicalTrials.gov NCT02215200.FUNDINGThe Leona M. and Harry B. Helmsley Charitable Trust (2019PG-T1D011), the NIH (R01 DK106191 Supplement, K08 DK128628), NIH TrialNet (U01 DK085461), and the NIH NIAID (P01 AI042288).


Asunto(s)
Suero Antilinfocítico , Diabetes Mellitus Tipo 1 , Humanos , Suero Antilinfocítico/uso terapéutico , Linfocitos T CD4-Positivos/metabolismo , Agotamiento de Células T , Péptido C , Factor Estimulante de Colonias de Granulocitos/metabolismo , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo
7.
Cell Rep Med ; 4(11): 101261, 2023 11 21.
Artículo en Inglés | MEDLINE | ID: mdl-37918404

RESUMEN

In preclinical models, α-difluoromethylornithine (DFMO), an ornithine decarboxylase (ODC) inhibitor, delays the onset of type 1 diabetes (T1D) by reducing ß cell stress. However, the mechanism of DFMO action and its human tolerability remain unclear. In this study, we show that mice with ß cell ODC deletion are protected against toxin-induced diabetes, suggesting a cell-autonomous role of ODC during ß cell stress. In a randomized controlled trial (ClinicalTrials.gov: NCT02384889) involving 41 recent-onset T1D subjects (3:1 drug:placebo) over a 3-month treatment period with a 3-month follow-up, DFMO (125-1,000 mg/m2) is shown to meet its primary outcome of safety and tolerability. DFMO dose-dependently reduces urinary putrescine levels and, at higher doses, preserves C-peptide area under the curve without apparent immunomodulation. Transcriptomics and proteomics of DFMO-treated human islets exposed to cytokine stress reveal alterations in mRNA translation, nascent protein transport, and protein secretion. These findings suggest that DFMO may preserve ß cell function in T1D through islet cell-autonomous effects.


Asunto(s)
Diabetes Mellitus Tipo 1 , Humanos , Ratones , Animales , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Ornitina Descarboxilasa/genética , Ornitina Descarboxilasa/metabolismo , Inhibidores de la Ornitina Descarboxilasa/farmacología , Eflornitina/farmacología , Eflornitina/uso terapéutico , Putrescina/metabolismo
8.
Front Immunol ; 8: 1503, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29209312

RESUMEN

Serial accumulation of mutations to fixation in the SLYNTVATL (SL9) immunodominant, HIV p17 Gag-derived, HLA A2-restricted cytotoxic T lymphocyte epitope produce the SLFNTIAVL triple mutant "ultimate" escape variant. These mutations in solvent-exposed residues are believed to interfere with TCR recognition, although confirmation has awaited structural verification. Here, we solved a TCR co-complex structure with SL9 and the triple escape mutant to determine the mechanism of immune escape in this eminent system. We show that, in contrast to prevailing hypotheses, the main TCR contact residue is 4N and the dominant mechanism of escape is not via lack of TCR engagement. Instead, mutation of solvent-exposed residues in the peptide destabilise the peptide-HLA and reduce peptide density at the cell surface. These results highlight the extraordinary lengths that HIV employs to evade detection by high-affinity TCRs with a broad peptide-binding footprint and necessitate re-evaluation of this exemplar model of HIV TCR escape.

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