Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Mais filtros

Base de dados
Intervalo de ano de publicação
Immunity ; 52(5): 825-841.e8, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32396847


CD8+ T cell exhaustion is a major barrier to current anti-cancer immunotherapies. Despite this, the developmental biology of exhausted CD8+ T cells (Tex) remains poorly defined, restraining improvement of strategies aimed at "re-invigorating" Tex cells. Here, we defined a four-cell-stage developmental framework for Tex cells. Two TCF1+ progenitor subsets were identified, one tissue restricted and quiescent and one more blood accessible, that gradually lost TCF1 as it divided and converted to a third intermediate Tex subset. This intermediate subset re-engaged some effector biology and increased upon PD-L1 blockade but ultimately converted into a fourth, terminally exhausted subset. By using transcriptional and epigenetic analyses, we identified the control mechanisms underlying subset transitions and defined a key interplay between TCF1, T-bet, and Tox in the process. These data reveal a four-stage developmental hierarchy for Tex cells and define the molecular, transcriptional, and epigenetic mechanisms that could provide opportunities to improve cancer immunotherapy.

Linfócitos T CD8-Positivos/imunologia , Epigênese Genética/imunologia , Neoplasias/imunologia , Subpopulações de Linfócitos T/imunologia , Transcrição Genética/imunologia , Animais , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/metabolismo , Células Cultivadas , Epigênese Genética/genética , Fator 1-alfa Nuclear de Hepatócito/genética , Fator 1-alfa Nuclear de Hepatócito/imunologia , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/imunologia , Humanos , Imunoterapia/métodos , Camundongos Endogâmicos C57BL , Neoplasias/genética , Neoplasias/terapia , Proteínas com Domínio T/genética , Proteínas com Domínio T/imunologia , Subpopulações de Linfócitos T/metabolismo , Transcrição Genética/genética
Nature ; 571(7764): 211-218, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31207603


Exhausted CD8+ T (Tex) cells in chronic infections and cancer have limited effector function, high co-expression of inhibitory receptors and extensive transcriptional changes compared with effector (Teff) or memory (Tmem) CD8+ T cells. Tex cells are important clinical targets of checkpoint blockade and other immunotherapies. Epigenetically, Tex cells are a distinct immune subset, with a unique chromatin landscape compared with Teff and Tmem cells. However, the mechanisms that govern the transcriptional and epigenetic development of Tex cells remain unknown. Here we identify the HMG-box transcription factor TOX as a central regulator of Tex cells in mice. TOX is largely dispensable for the formation of Teff and Tmem cells, but it is critical for exhaustion: in the absence of TOX, Tex cells do not form. TOX is induced by calcineurin and NFAT2, and operates in a feed-forward loop in which it becomes calcineurin-independent and sustained in Tex cells. Robust expression of TOX therefore results in commitment to Tex cells by translating persistent stimulation into a distinct Tex cell transcriptional and epigenetic developmental program.

Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Epistasia Genética , Proteínas de Homeodomínio/metabolismo , Transcrição Genética , Animais , Calcineurina/metabolismo , Sinalização do Cálcio , Retroalimentação Fisiológica , Feminino , Regulação da Expressão Gênica/imunologia , Genótipo , Memória Imunológica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fatores de Transcrição NFATC/metabolismo , Evasão Tumoral
Nat Med ; 25(3): 454-461, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30804515


Immunologic responses to anti-PD-1 therapy in melanoma patients occur rapidly with pharmacodynamic T cell responses detectable in blood by 3 weeks. It is unclear, however, whether these early blood-based observations translate to the tumor microenvironment. We conducted a study of neoadjuvant/adjuvant anti-PD-1 therapy in stage III/IV melanoma. We hypothesized that immune reinvigoration in the tumor would be detectable at 3 weeks and that this response would correlate with disease-free survival. We identified a rapid and potent anti-tumor response, with 8 of 27 patients experiencing a complete or major pathological response after a single dose of anti-PD-1, all of whom remain disease free. These rapid pathologic and clinical responses were associated with accumulation of exhausted CD8 T cells in the tumor at 3 weeks, with reinvigoration in the blood observed as early as 1 week. Transcriptional analysis demonstrated a pretreatment immune signature (neoadjuvant response signature) that was associated with clinical benefit. In contrast, patients with disease recurrence displayed mechanisms of resistance including immune suppression, mutational escape, and/or tumor evolution. Neoadjuvant anti-PD-1 treatment is effective in high-risk resectable stage III/IV melanoma. Pathological response and immunological analyses after a single neoadjuvant dose can be used to predict clinical outcome and to dissect underlying mechanisms in checkpoint blockade.

Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Procedimentos Cirúrgicos Dermatológicos , Melanoma/tratamento farmacológico , Neoplasias Cutâneas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Linfócitos T CD8-Positivos , Quimioterapia Adjuvante , Feminino , Perfilação da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Terapia Neoadjuvante , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Neoplasias Cutâneas/patologia , Transcriptoma , Evasão Tumoral
J Am Chem Soc ; 137(2): 616-9, 2015 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25564133


A small-ring phosphacycle is found to catalyze the deoxygenative condensation of α-keto esters and carboxylic acids. The reaction provides a chemoselective catalytic synthesis of α-acyloxy ester products with good functional group compatibility. Based on both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic P(III)/P(V)═O cycling. The importance of ring strain in the phosphacyclic catalyst is substantiated by an observed temperature-dependent product selectivity effect. The results point to an inherent distinction in design criteria for organophosphorus-based catalysts operating via P(III)/P(V)═O redox cycling as opposed to Lewis base (nucleophilic) catalysis.