Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 201
Filtrar
1.
J Refract Surg ; 40(4): e208-e217, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38593256

RESUMO

PURPOSE: To evaluate spherical intraocular lens (IOL) implantation for cataracts in keratoconic eyes followed by optional refractive toric lens exchange to improve uncorrected visual acuity. METHODS: This retrospective study evaluated cataract surgery outcomes in keratoconic eyes. Eyes treated with a spherical IOL targeted for -2.00 diopters (D) either achieved acceptable manifest refraction and desired exchange with a toric IOL (Group 1); achieved satisfactory manifest refraction and chose to use spectacles or contact lenses (Group 2); or did not achieve acceptable refraction and used contact lenses (Group 3). Group 4 had single-stage toric IOL implantation with plano target. Corrected and uncorrected distance visual acuity (CDVA and UDVA) and keratometry were analyzed. RESULTS: Groups 1 to 4 had 18, 23, 18, and 26 eyes, respectively. A staged toric exchange resulted in significantly better (P = .02) UDVA (mean: 0.15 logMAR; 20/25 Snellen) than initial toric IOL implantation (0.24 logMAR; 20/30 Snellen). All toric IOL exchange eyes achieved 20/30 or better CDVA and 94% had 20/40 or better UDVA. Mean manifest cylinder significantly decreased from 3.39 D before lens exchange to 1.10 D postoperatively. CONCLUSIONS: Initial implantation of a spherical IOL in keratoconic eyes allows basing toric calculations on the manifest refraction, which may be more reliable than keratometry measurements in keratoconic eyes. UDVA after staged toric IOL exchange was significantly better than after initial toric IOL implantation. Importantly, by staging use of toric lenses, the authors avoided cases where patients required a rigid contact lens after a toric IOL was implanted. [J Refract Surg. 2024;40(4):e207-e217.].


Assuntos
Astigmatismo , Catarata , Ceratocone , Lentes Intraoculares , Facoemulsificação , Humanos , Ceratocone/complicações , Ceratocone/cirurgia , Estudos Retrospectivos , Facoemulsificação/métodos , Resultado do Tratamento , Astigmatismo/cirurgia , Refração Ocular , Catarata/complicações
2.
Cornea ; 43(3): 323-326, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37155339

RESUMO

PURPOSE: The aim of this study was to assess the long-term risk of steroid-induced ocular hypertension and the need for glaucoma treatment with long-term use of topical prednisolone acetate 1% in patients without preexisting glaucoma. METHODS: We retrospectively reviewed the charts of 211 patients without previous glaucoma, who underwent Descemet stripping endothelial keratoplasty (DSEK) and used topical prednisolone acetate long-term to prevent graft rejection. Dosing was 4 times daily for 4 months and tapered to once daily. The main outcomes were ocular hypertension (defined as intraocular pressure ≥24 mm Hg, or increase of ≥10 mm Hg over baseline) and initiation of glaucoma treatment. RESULTS: The median patient age was 70 years (range: 34-94 years). The indications for DSEK were Fuchs dystrophy (88%), pseudophakic corneal edema (7%), failed DSEK (3%), and failed penetrating keratoplasty (2%). The median follow-up period was 7 years (range, 1-17 years). At 1, 5, and 10 years, the cumulative risks of steroid-induced ocular hypertension were 29%, 41%, and 49%, respectively, and the risks of requiring glaucoma treatment were 11%, 17%, and 25%, respectively. Among 35 eyes treated for glaucoma, 28 (80%) were managed medically and 7 (20%) had filtration surgery. CONCLUSIONS: Long-term use of potent topical corticosteroids, such as prednisolone acetate 1%, entails substantial risk of developing steroid-induced ocular hypertension, so frequent monitoring of intraocular pressure is required. With corneal transplantation, the risk can be mitigated by using techniques with a low inherent risk of rejection, such as Descemet membrane endothelial keratoplasty, whenever possible, to allow earlier reduction of steroid potency.


Assuntos
Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior , Glaucoma , Hipertensão Ocular , Prednisolona/análogos & derivados , Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Estudos Retrospectivos , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior/efeitos adversos , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior/métodos , Glaucoma/induzido quimicamente , Glaucoma/cirurgia , Hipertensão Ocular/induzido quimicamente , Hipertensão Ocular/cirurgia , Pressão Intraocular , Ceratoplastia Penetrante/métodos
3.
J Cataract Refract Surg ; 50(3): 270-275, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38085175

RESUMO

PURPOSE: To evaluate the use of light-adjustable intraocular lenses (LALs) to maximize visual acuity (VA) postoperatively in eyes undergoing combined Descemet membrane endothelial keratoplasty (DMEK) and cataract surgery. SETTING: Private practice, tertiary referral center. DESIGN: Retrospective review of initial case series. METHODS: Patients with Fuchs endothelial dystrophy had DMEK combined with phacoemulsification and LAL implantation. Lenses were adjusted based on postoperative manifest refraction and locked-in 3 to 6 months postoperatively. Adjustments to the LAL were started after stabilization of refraction at sequential examinations. Outcomes were uncorrected near and distance VA and manifest refraction 3 to 6 months after locking the lens. RESULTS: A total of 27 eyes in 17 patients with mean age of 65 years (range 53 to 75 years) were included in this study. 6 eyes (22%) had either a near or intermediate target, and 21 eyes (78%) had a distance target. After lock-in, 57% of eyes with a distance target had uncorrected distance VA (UDVA) of 20/20 or better, 90% were 20/25 or better, and 100% were 20/40 or better. After lens lock-in, 100% of eyes had corrected distance VA (CDVA) of 20/20 or better, 86% had postoperative UDVA the same or better than preoperative CDVA, and 100% of eyes had UDVA within 1 line of the preoperative CDVA. In total, 93% of eyes were within 1 diopter (D) of spherical target, and 93% of eyes had ≤0.5 D of refractive cylinder postoperatively. CONCLUSIONS: Combining DMEK with LAL implantation provided significantly better UDVA and refractive outcomes than previously reported data on combined implantation of a standard monofocal lens.


Assuntos
Extração de Catarata , Catarata , Transplante de Córnea , Lentes Intraoculares , Facoemulsificação , Humanos , Pessoa de Meia-Idade , Idoso , Implante de Lente Intraocular , Refração Ocular , Endotélio Corneano , Estudos Retrospectivos
4.
Proc Natl Acad Sci U S A ; 120(33): e2303155120, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37561786

RESUMO

Human cytomegalovirus (HCMV) is a major human pathogen whose life-long persistence is enabled by its remarkable capacity to systematically subvert host immune defenses. In exploring the finding that HCMV infection up-regulates tumor necrosis factor receptor 2 (TNFR2), a ligand for the pro-inflammatory antiviral cytokine TNFα, we found that the underlying mechanism was due to targeting of the protease, A Disintegrin And Metalloproteinase 17 (ADAM17). ADAM17 is the prototype 'sheddase', a family of proteases that cleaves other membrane-bound proteins to release biologically active ectodomains into the supernatant. HCMV impaired ADAM17 surface expression through the action of two virally-encoded proteins in its UL/b' region, UL148 and UL148D. Proteomic plasma membrane profiling of cells infected with an HCMV double-deletion mutant for UL148 and UL148D with restored ADAM17 expression, combined with ADAM17 functional blockade, showed that HCMV stabilized the surface expression of 114 proteins (P < 0.05) in an ADAM17-dependent fashion. These included reported substrates of ADAM17 with established immunological functions such as TNFR2 and jagged1, but also numerous unreported host and viral targets, such as nectin1, UL8, and UL144. Regulation of TNFα-induced cytokine responses and NK inhibition during HCMV infection were dependent on this impairment of ADAM17. We therefore identify a viral immunoregulatory mechanism in which targeting a single sheddase enables broad regulation of multiple critical surface receptors, revealing a paradigm for viral-encoded immunomodulation.


Assuntos
Citomegalovirus , Fator de Necrose Tumoral alfa , Humanos , Citomegalovirus/fisiologia , Fator de Necrose Tumoral alfa/metabolismo , Proteoma/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Proteômica , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Citocinas/metabolismo , Membrana Celular/metabolismo , Metaloproteases/metabolismo , Proteína ADAM17/genética , Proteína ADAM17/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas Virais/metabolismo
5.
Elife ; 122023 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-37440306

RESUMO

Inhibitory CD4+ T cells have been linked with suboptimal immune responses against cancer and pathogen chronicity. However, the mechanisms that underpin the development of these regulatory cells, especially in the context of ongoing antigen exposure, have remained obscure. To address this knowledge gap, we undertook a comprehensive functional, phenotypic, and transcriptomic analysis of interleukin (IL)-10-producing CD4+ T cells induced by chronic infection with murine cytomegalovirus (MCMV). We identified these cells as clonally expanded and highly differentiated TH1-like cells that developed in a T-bet-dependent manner and coexpressed arginase-1 (Arg1), which promotes the catalytic breakdown of L-arginine. Mice lacking Arg1-expressing CD4+ T cells exhibited more robust antiviral immunity and were better able to control MCMV. Conditional deletion of T-bet in the CD4+ lineage suppressed the development of these inhibitory cells and also enhanced immune control of MCMV. Collectively, these data elucidated the ontogeny of IL-10-producing CD4+ T cells and revealed a previously unappreciated mechanism of immune regulation, whereby viral persistence was facilitated by the site-specific delivery of Arg1.


Assuntos
Citomegalovirus , Muromegalovirus , Camundongos , Animais , Interleucina-10 , Linfócitos T CD4-Positivos , Arginase/genética , Muromegalovirus/fisiologia
6.
J Biol Chem ; 299(8): 104981, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37390984

RESUMO

CD8+ T cell-mediated recognition of peptide-major histocompatibility complex class I (pMHCI) molecules involves cooperative binding of the T cell receptor (TCR), which confers antigen specificity, and the CD8 coreceptor, which stabilizes the TCR/pMHCI complex. Earlier work has shown that the sensitivity of antigen recognition can be regulated in vitro by altering the strength of the pMHCI/CD8 interaction. Here, we characterized two CD8 variants with moderately enhanced affinities for pMHCI, aiming to boost antigen sensitivity without inducing non-specific activation. Expression of these CD8 variants in model systems preferentially enhanced pMHCI antigen recognition in the context of low-affinity TCRs. A similar effect was observed using primary CD4+ T cells transduced with cancer-targeting TCRs. The introduction of high-affinity CD8 variants also enhanced the functional sensitivity of primary CD8+ T cells expressing cancer-targeting TCRs, but comparable results were obtained using exogenous wild-type CD8. Specificity was retained in every case, with no evidence of reactivity in the absence of cognate antigen. Collectively, these findings highlight a generically applicable mechanism to enhance the sensitivity of low-affinity pMHCI antigen recognition, which could augment the therapeutic efficacy of clinically relevant TCRs.


Assuntos
Antígenos CD8 , Linfócitos T CD8-Positivos , Antígenos de Histocompatibilidade Classe I , Ativação Linfocitária , Antígenos de Histocompatibilidade Classe I/metabolismo , Peptídeos/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Humanos
7.
Sci Rep ; 13(1): 8011, 2023 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-37198258

RESUMO

Adoptive immune therapies based on the transfer of antigen-specific T cells have been used successfully to treat various cancers and viral infections, but improved techniques are needed to identify optimally protective human T cell receptors (TCRs). Here we present a high-throughput approach to the identification of natively paired human TCRα and TCRß (TCRα:ß) genes encoding heterodimeric TCRs that recognize specific peptide antigens bound to major histocompatibility complex molecules (pMHCs). We first captured and cloned TCRα:ß genes from individual cells, ensuring fidelity using a suppression PCR. We then screened TCRα:ß libraries expressed in an immortalized cell line using peptide-pulsed antigen-presenting cells and sequenced activated clones to identify the cognate TCRs. Our results validated an experimental pipeline that allows large-scale repertoire datasets to be annotated with functional specificity information, facilitating the discovery of therapeutically relevant TCRs.


Assuntos
Receptores de Antígenos de Linfócitos T , Linfócitos T , Humanos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Clonagem Molecular , Antígenos , Peptídeos/genética
8.
Lancet Haematol ; 10(5): e346-e358, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37011643

RESUMO

BACKGROUND: Lymphomatoid granulomatosis is a rare Epstein-Barr virus-associated B-cell lymphoproliferative disorder with a median overall survival of less than 2 years. In this study, we hypothesised that low-grade lymphomatoid granulomatosis is immune-dependent and high-grade lymphomatoid granulomatosis is immune-independent. On the basis of this hypothesis, we investigated the activity and safety of new treatment with immunotherapy in patients with low-grade disease and standard chemotherapy in patients with high-grade disease. METHODS: In this open-label, single-centre, phase 2 trial, we enrolled patients aged 12 years or older with untreated, or relapsed or refractory lymphomatoid granulomatosis at the National Cancer Institute (National Institutes of Health, Bethesda, MD, USA). Patients with low-grade disease received dose-escalated interferon alfa-2b, starting at 7·5 million international units subcutaneously three times per week for up to 1 year past best response, and patients with high-grade disease received six cycles every 3 weeks of intravenous, dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (DA-EPOCH-R). Starting doses were 50 mg/m2 per day as a continuous intravenous infusion from day 1 to day 4 (96 h) for etoposide; 60 mg/m2 twice daily by mouth from day 1 to day 5 for prednisone; 0·4 mg/m2 per day as a continuous intravenous infusion from day 1 to day 4 (96 h) for vincristine; 750 mg/m2 intravenous on day 5 for cyclophosphamide; 10 mg/m2 per day as a continuous intravenous infusion from day 1 to day 4 (96 h) for doxorubicin; and 375 mg/m2 intravenous on day 1 for rituximab. The doses of doxorubicin, etoposide, and cyclophosphamide were adjusted up or down on the basis of neutrophil and platelet nadirs. Patients with residual or progressive disease after initial therapy crossed over to alternative therapy. The primary endpoint was the proportion of patients who had an overall response and the 5-year progression-free survival after initial or cross-over treatment. Analysis of response included all participants who underwent restaging imaging; safety analysis included all patients who received any dose of study drugs. The trial is open for enrolment and is registered at ClinicalTrials.gov, NCT00001379. FINDINGS: 67 patients were enrolled between Jan 10, 1991, and Sept 5, 2019 (42 [63%] were male). 45 patients received initial treatment with interferon alfa-2b (16 of whom crossed over to DA-EPOCH-R) and 18 received initial treatment with DA-EPOCH-R (eight of whom crossed over to interferon alfa-2b); four underwent surveillance only. After initial treatment with interferon alfa-2b, the overall response was 64% (28 of 44 evaluable patients) with 61% (27 of 44) having a complete response, whereas, after cross-over treatment with interferon alfa-2b, the overall response was 63% (five of eight evaluable patients) with 50% (four of eight) having a complete response. After initial treatment with DA-EPOCH-R, the overall response was 76% (13 of 17 evaluable patients) with 47% (eight of 17) having a complete response, whereas, after cross-over treatment with DA-EPOCH-R, the overall response was 67% (ten of 15 evaluable patients) with 47% (seven of 15) having a complete response. 5-year progression-free survival was 48·5% (95% CI 33·2-62·1) after initial treatment with interferon alfa-2b, 50·0% (15·2-77·5) after cross-over treatment with interferon alfa-2b, 25·4% (8·2-47·2) after initial treatment with DA-EPOCH-R, and 62·5% (34·9-81·1) after cross-over treatment with DA-EPOCH-R. The most common grade 3 or worse adverse events in patients treated with interferon alfa-2b included neutropenia (27 [53%] of 51 patients), lymphopenia (24 [47%]), and leukopenia (24 [47%]). The four most common grade 3 or worse adverse events in patients treated with DA-EPOCH-R included neutropenia (29 [88%] of 33 patients), leukopenia (28 [85%]), infection (18 [55%]), and lymphopenia (17 [52%]). Serious adverse events occurred in 13 (25%) of 51 patients receiving treatment with interferon alfa-2b and 21 (64%) of 33 patients receiving DA-EPOCH-R, with five treatment-related deaths: one thromboembolic, one infection, and one haemophagocytic syndrome with interferon alfa-2b, and one infection and one haemophagocytic syndrome with DA-EPOCH-R. INTERPRETATION: Interferon alfa-2b is efficacious for treating low-grade lymphomatoid granulomatosis and hence reducing progression to high-grade disease, whereas patients with high-grade lymphomatoid granulomatosis showed expected responses to chemotherapy. Uncontrolled immune regulation of Epstein-Barr virus is hypothesised to result in the emergence of low-grade disease after chemotherapy, for which treatment with interferon alfa-2b is efficacious. FUNDING: Intramural Research Programs of the National Cancer Institute and National Institute of Allergy and Infectious Diseases, National Institutes of Health.


Assuntos
Infecções por Vírus Epstein-Barr , Linfo-Histiocitose Hemofagocítica , Linfoma Difuso de Grandes Células B , Linfoma não Hodgkin , Granulomatose Linfomatoide , Linfopenia , Neutropenia , Humanos , Masculino , Feminino , Vincristina/efeitos adversos , Prednisona/uso terapêutico , Etoposídeo/uso terapêutico , Rituximab/efeitos adversos , Interferon alfa-2/uso terapêutico , Infecções por Vírus Epstein-Barr/induzido quimicamente , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/tratamento farmacológico , Granulomatose Linfomatoide/tratamento farmacológico , Granulomatose Linfomatoide/induzido quimicamente , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Herpesvirus Humano 4 , Linfoma não Hodgkin/tratamento farmacológico , Ciclofosfamida/efeitos adversos , Doxorrubicina/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neutropenia/etiologia , Linfopenia/induzido quimicamente , Linfopenia/tratamento farmacológico
9.
Retina ; 42(10): 1926-1930, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35976221

RESUMO

PURPOSE: To assess whether the repeated use of intravitreal bevacizumab injections in treatment of proliferative diabetic retinopathy is associated with a long-term decline in the glomerular filtration rate (GFR). METHODS: Three hundred charts were retrospectively reviewed, of which 60 patients met the criteria for inclusion. The criteria were as follows: reception of at least one bevacizumab injection, baseline GFR before initial bevacizumab injection, and end GFR 6 to 24 months after baseline. Analysis controlled for time between baseline and end GFR measurements, blood pressure, hemoglobin A1C, race, sex, age, and use of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. Significance testing was performed with step-wise multiple linear regression. The significance threshold was 5%, and all tests were two-sided. RESULTS: Patients received a range of 1 to 17 injections (average 3.6). The average baseline GFR was 76 ± 38 mL/minute, and the end GFR was 63 ± 39 mL/min. The number of injections patients received was not associated with end GFR ( P = 0.72), GFR reduction ( P = 0.88), or percent GFR reduction ( P = 0.49). CONCLUSION: Increased number of intravitreal bevacizumab injections at therapeutic dosage was not associated with reduced GFR in patients with proliferative diabetic retinopathy. This study supports that intravitreal antivascular endothelial growth factor agents are renally safe.


Assuntos
Bevacizumab , Diabetes Mellitus , Retinopatia Diabética , Inibidores da Angiogênese , Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Bevacizumab/uso terapêutico , Retinopatia Diabética/complicações , Retinopatia Diabética/diagnóstico , Retinopatia Diabética/tratamento farmacológico , Fatores de Crescimento Endotelial , Taxa de Filtração Glomerular , Hemoglobinas Glicadas , Humanos , Injeções Intravítreas , Estudos Retrospectivos
10.
J Med Chem ; 65(12): 8208-8226, 2022 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-35647711

RESUMO

Peptide agonists of the glucagon-like peptide-1 receptor (GLP-1R) have revolutionized diabetes therapy, but their use has been limited because they require injection. Herein, we describe the discovery of the orally bioavailable, small-molecule, GLP-1R agonist PF-06882961 (danuglipron). A sensitized high-throughput screen was used to identify 5-fluoropyrimidine-based GLP-1R agonists that were optimized to promote endogenous GLP-1R signaling with nanomolar potency. Incorporation of a carboxylic acid moiety provided considerable GLP-1R potency gains with improved off-target pharmacology and reduced metabolic clearance, ultimately resulting in the identification of danuglipron. Danuglipron increased insulin levels in primates but not rodents, which was explained by receptor mutagensis studies and a cryogenic electron microscope structure that revealed a binding pocket requiring a primate-specific tryptophan 33 residue. Oral administration of danuglipron to healthy humans produced dose-proportional increases in systemic exposure (NCT03309241). This opens an opportunity for oral small-molecule therapies that target the well-validated GLP-1R for metabolic health.


Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1 , Hipoglicemiantes , Animais , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Humanos , Hipoglicemiantes/farmacologia , Peptídeos/química
11.
Kidney Int Rep ; 7(4): 786-796, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35497797

RESUMO

Introduction: Variants of the APOL1 gene are associated with chronic kidney disease (CKD) in people of African ancestry, although evidence for their impact in people with HIV are sparse. Methods: We conducted a cross-sectional study investigating the association between APOL1 renal risk alleles and kidney disease in people of African ancestry with HIV in the UK. The primary outcome was end-stage kidney disease (ESKD; estimated glomerular filtration rate [eGFR] of <15 ml/min per 1.73 m2, chronic dialysis, or having received a kidney transplant). The secondary outcomes included renal impairment (eGFR <60 ml/min per 1.73 m2), albuminuria (albumin-to-creatinine ratio [ACR] >30 mg/mmol), and biopsy-proven HIV-associated nephropathy (HIVAN). Multivariable logistic regression was used to estimate the associations between APOL1 high-risk genotypes (G1/G1, G1/G2, G2/G2) and kidney disease outcomes. Results: A total of 2864 participants (mean age 48.1 [SD 10.3], 57.3% female) were genotyped, of whom, 354 (12.4%) had APOL1 high-risk genotypes, and 99 (3.5%) had ESKD. After adjusting for demographic, HIV, and renal risk factors, individuals with APOL1 high-risk genotypes were at increased odds of ESKD (odds ratio [OR] 10.58, 95% CI 6.22-17.99), renal impairment (OR 5.50, 95% CI 3.81-7.95), albuminuria (OR 3.34, 95% CI 2.00-5.56), and HIVAN (OR 30.16, 95% CI 12.48-72.88). An estimated 49% of ESKD was attributable to APOL1 high-risk genotypes. Conclusion: APOL1 high-risk genotypes were strongly associated with kidney disease in people of African ancestry with HIV and accounted for approximately half of ESKD cases in this cohort.

12.
Cell Rep ; 38(9): 110449, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35235807

RESUMO

Cytotoxic T lymphocyte (CTL) and natural killer (NK) cell responses to a single optimal 10-mer epitope (KK10) in the human immunodeficiency virus type-1 (HIV-1) protein p24Gag are associated with enhanced immune control in patients expressing human leukocyte antigen (HLA)-B∗27:05. We find that proteasomal activity generates multiple length variants of KK10 (4-14 amino acids), which bind TAP and HLA-B∗27:05. However, only epitope forms ≥8 amino acids evoke peptide length-specific and cross-reactive CTL responses. Structural analyses reveal that all epitope forms bind HLA-B∗27:05 via a conserved N-terminal motif, and competition experiments show that the truncated epitope forms outcompete immunogenic epitope forms for binding to HLA-B∗27:05. Common viral escape mutations abolish (L136M) or impair (R132K) production of KK10 and longer epitope forms. Peptide length influences how well the inhibitory NK cell receptor KIR3DL1 binds HLA-B∗27:05 peptide complexes and how intraepitope mutations affect this interaction. These results identify a viral escape mechanism from CTL and NK responses based on differential antigen processing and peptide competition.


Assuntos
Infecções por HIV , HIV-1 , Sequência de Aminoácidos , Aminoácidos , Apresentação de Antígeno , Epitopos de Linfócito T , Antígenos HLA-B/genética , Humanos , Peptídeos
13.
Protein Eng Des Sel ; 352022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35174859

RESUMO

Functional analyses of the T cell receptor (TCR) landscape can reveal critical information about protection from disease and molecular responses to vaccines. However, it has proven difficult to combine advanced next-generation sequencing technologies with methods to decode the peptide-major histocompatibility complex (pMHC) specificity of individual TCRs. We developed a new high-throughput approach to enable repertoire-scale functional evaluations of natively paired TCRs. In particular, we leveraged the immortalized nature of physically linked TCRα:ß amplicon libraries to analyze binding against multiple recombinant pMHCs on a repertoire scale, and to exemplify the utility of this approach, we also performed affinity-based functional mapping in conjunction with quantitative next-generation sequencing to track antigen-specific TCRs. These data successfully validated a new immortalization and screening platform to facilitate detailed molecular analyses of disease-relevant antigen interactions with human TCRs.


Assuntos
Receptores de Antígenos de Linfócitos T alfa-beta , Receptores de Antígenos de Linfócitos T , Antígenos , Humanos , Peptídeos/química , Receptores de Antígenos de Linfócitos T/química , Receptores de Antígenos de Linfócitos T alfa-beta/genética
14.
J Immunol ; 208(3): 562-570, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35031578

RESUMO

Aging is associated with functional deficits in the naive T cell compartment, which compromise the generation of de novo immune responses against previously unencountered Ags. The mechanisms that underlie this phenomenon have nonetheless remained unclear. We found that naive CD8+ T cells in elderly humans were prone to apoptosis and proliferated suboptimally in response to stimulation via the TCR. These abnormalities were associated with dysregulated lipid metabolism under homeostatic conditions and enhanced levels of basal activation. Importantly, reversal of the bioenergetic anomalies with lipid-altering drugs, such as rosiglitazone, almost completely restored the Ag responsiveness of naive CD8+ T cells. Interventions that favor lipid catabolism may therefore find utility as adjunctive therapies in the elderly to promote vaccine-induced immunity against targetable cancers and emerging pathogens, such as seasonal influenza viruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).


Assuntos
Envelhecimento/imunologia , Linfócitos T CD8-Positivos/imunologia , Imunocompetência/efeitos dos fármacos , Metabolismo dos Lipídeos , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose , Linfócitos T CD8-Positivos/metabolismo , COVID-19/imunologia , Vacinas Anticâncer/imunologia , Divisão Celular , Feminino , Fenofibrato/farmacologia , Glucose/metabolismo , Antígeno HLA-A2/imunologia , Humanos , Hipolipemiantes/farmacologia , Hipolipemiantes/uso terapêutico , Influenza Humana/imunologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Ativação Linfocitária , Antígeno MART-1/química , Antígeno MART-1/imunologia , Masculino , Pessoa de Meia-Idade , Neoplasias/imunologia , Fragmentos de Peptídeos/imunologia , Rosiglitazona/farmacologia , Método Simples-Cego , Vacinação , Vacinas Virais/imunologia , Adulto Jovem
15.
Sci Immunol ; 6(64): eabk0894, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34519539

RESUMO

Cross-reactive CD4+ T cells that recognize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are more commonly detected in the peripheral blood of unexposed individuals compared with SARS-CoV-2­reactive CD8+ T cells. However, large numbers of memory CD8+ T cells reside in tissues, feasibly harboring localized SARS-CoV-2­specific immune responses. To test this idea, we performed a comprehensive functional and phenotypic analysis of virus-specific T cells in tonsils, a major lymphoid tissue site in the upper respiratory tract, and matched peripheral blood samples obtained from children and adults before the emergence of COVID-19 (coronavirus disease 2019). We found that SARS-CoV-2­specific memory CD4+ T cells could be found at similar frequencies in the tonsils and peripheral blood in unexposed individuals, whereas functional SARS-CoV-2­specific memory CD8+ T cells were almost only detectable in the tonsils. Tonsillar SARS-CoV-2­specific memory CD8+ T cells displayed a follicular homing and tissue-resident memory phenotype, similar to tonsillar Epstein-Barr virus­specific memory CD8+ T cells, but were functionally less potent than other virus-specific memory CD8+ T cell responses. The presence of preexisting tissue-resident memory CD8+ T cells in unexposed individuals could potentially enable rapid sentinel immune responses against SARS-CoV-2.


Assuntos
Tonsila Faríngea/imunologia , Linfócitos T CD8-Positivos/imunologia , SARS-CoV-2/imunologia , Tonsila Faríngea/citologia , Adulto , Idoso , Pré-Escolar , Feminino , Citometria de Fluxo , Humanos , Masculino , Pessoa de Meia-Idade
16.
Proc Natl Acad Sci U S A ; 118(29)2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34272276

RESUMO

CD8+ T cells are inherently cross-reactive and recognize numerous peptide antigens in the context of a given major histocompatibility complex class I (MHCI) molecule via the clonotypically expressed T cell receptor (TCR). The lineally expressed coreceptor CD8 interacts coordinately with MHCI at a distinct and largely invariant site to slow the TCR/peptide-MHCI (pMHCI) dissociation rate and enhance antigen sensitivity. However, this biological effect is not necessarily uniform, and theoretical models suggest that antigen sensitivity can be modulated in a differential manner by CD8. We used two intrinsically controlled systems to determine how the relationship between the TCR/pMHCI interaction and the pMHCI/CD8 interaction affects the functional sensitivity of antigen recognition. Our data show that modulation of the pMHCI/CD8 interaction can reorder the agonist hierarchy of peptide ligands across a spectrum of affinities for the TCR.


Assuntos
Antígenos CD8/imunologia , Peptídeos/agonistas , Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Antígenos/química , Antígenos/imunologia , Linfócitos T CD8-Positivos/imunologia , Reações Cruzadas , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Cinética , Ligantes , Ativação Linfocitária , Modelos Imunológicos , Mutação
17.
EClinicalMedicine ; 38: 101006, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34286237

RESUMO

BACKGROUND: Chronic kidney disease (CKD) is a leading cause of morbidity and mortality globally. The risk of CKD is increased in people of African ancestry and with Human Immunodeficiency Virus (HIV) infection. METHODS: We conducted a cross-sectional study investigating the relationship between region of ancestry (East, Central, South or West Africa) and kidney disease in people of sub-Saharan African ancestry with HIV in the UK between May 2018 and February 2020. The primary outcome was renal impairment (estimated glomerular filtration rate [eGFR] of <60 mL/min/1.73 m2). Secondary outcomes were stage 5 CKD (eGFR <15 ml/min/1.73 m2, on dialysis for over 3 months or who had received a kidney transplant), proteinuria (urine protein/creatinine ratio >50 mg/mmol), and biopsy-confirmed HIV-associated nephropathy (HIVAN), focal segmental glomerulosclerosis (FSGS) or arterionephrosclerosis. Multivariable robust Poisson regression estimated the effect of region of African ancestry on kidney disease outcomes. FINDINGS: Of the 2468 participants (mean age 48.1 [SD 9.8] years, 62% female), 193 had renal impairment, 87 stage 5 CKD, 126 proteinuria, and 43 HIVAN/FSGS or arterionephrosclerosis. After adjusting for demographic characteristics, HIV and several CKD risk factors and with East African ancestry as referent, West African ancestry was associated with renal impairment (prevalence ratio [PR] 2.06 [95% CI 1.40-3.04]) and stage 5 CKD (PR 2.23 [1.23-4.04]), but not with proteinuria (PR 1.27 [0.78-2.05]). West African ancestry (as compared to East/South African ancestry) was also strongly associated with a diagnosis of HIVAN/FSGS or arterionephrosclerosis on kidney biopsy (PR 6.44 [2.42-17.14]). INTERPRETATION: Our results indicate that people of West African ancestry with HIV are at increased risk of kidney disease. Although we cannot rule out the possibility of residual confounding, geographical region of origin appears to be a strong independent risk factor for CKD as the association did not appear to be explained by several demographic, HIV or renal risk factors.

18.
J Immunol ; 207(4): 1009-1017, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34321228

RESUMO

The human CD8+ T cell clone 6C5 has previously been shown to recognize the tert-butyl-modified Bax161-170 peptide LLSY(3-tBu)FGTPT presented by HLA-A*02:01. This nonnatural epitope was likely created as a by-product of fluorenylmethoxycarbonyl protecting group peptide synthesis and bound poorly to HLA-A*02:01. In this study, we used a systematic approach to identify and characterize natural ligands for the 6C5 TCR. Functional analyses revealed that 6C5 T cells only recognized the LLSYFGTPT peptide when tBu was added to the tyrosine residue and did not recognize the LLSYFGTPT peptide modified with larger (di-tBu) or smaller chemical groups (Me). Combinatorial peptide library screening further showed that 6C5 T cells recognized a series of self-derived peptides with dissimilar amino acid sequences to LLSY(3-tBu)FGTPT. Structural studies of LLSY(3-tBu)FGTPT and two other activating nonamers (IIGWMWIPV and LLGWVFAQV) in complex with HLA-A*02:01 demonstrated similar overall peptide conformations and highlighted the importance of the position (P) 4 residue for T cell recognition, particularly the capacity of the bulky amino acid tryptophan to substitute for the tBu-modified tyrosine residue in conjunction with other changes at P5 and P6. Collectively, these results indicated that chemical modifications directly altered the immunogenicity of a synthetic peptide via molecular mimicry, leading to the inadvertent activation of a T cell clone with unexpected and potentially autoreactive specificities.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Ativação Linfocitária/imunologia , Fragmentos de Peptídeos/imunologia , Peptídeos/imunologia , Sequência de Aminoácidos , Apresentação de Antígeno/imunologia , Células Cultivadas , Epitopos de Linfócito T/imunologia , Humanos , Ligantes , Biblioteca de Peptídeos
19.
Vaccines (Basel) ; 9(5)2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34069535

RESUMO

Peptide vaccines incorporating B- and T-cell epitopes have shown promise in the context of various cancers and infections. These vaccines are relatively simple to manufacture, but more immunogenic formulations are considered a priority. We developed tetrabranched derivatives for this purpose based on a novel peptide welding technology (PWT). PWTs provide molecular scaffolds for the efficient synthesis of ultrapure peptide dendrimers, which allow the delivery of multiple ligands within a single macromolecular structure. Peptide vaccines incorporating T-cell epitopes derived from melanoma and B-cell epitopes derived from human immunodeficiency virus, synthesized using this approach, elicited primary immune responses in vitro and in vivo. Subcutaneous administration of the B-cell epitope-based vaccines also elicited more potent humoral responses than subcutaneous administration of the corresponding peptides alone. Highly immunogenic peptide epitope-based vaccines can therefore be generated quickly and easily using a novel PWT.

20.
Cell ; 183(7): 1946-1961.e15, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33306960

RESUMO

Lymphocyte migration is essential for adaptive immune surveillance. However, our current understanding of this process is rudimentary, because most human studies have been restricted to immunological analyses of blood and various tissues. To address this knowledge gap, we used an integrated approach to characterize tissue-emigrant lineages in thoracic duct lymph (TDL). The most prevalent immune cells in human and non-human primate efferent lymph were T cells. Cytolytic CD8+ T cell subsets with effector-like epigenetic and transcriptional signatures were clonotypically skewed and selectively confined to the intravascular circulation, whereas non-cytolytic CD8+ T cell subsets with stem-like epigenetic and transcriptional signatures predominated in tissues and TDL. Moreover, these anatomically distinct gene expression profiles were recapitulated within individual clonotypes, suggesting parallel differentiation programs independent of the expressed antigen receptor. Our collective dataset provides an atlas of the migratory immune system and defines the nature of tissue-emigrant CD8+ T cells that recirculate via TDL.


Assuntos
Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Animais , Diferenciação Celular , Células Clonais , Citotoxicidade Imunológica , Epigênese Genética , Humanos , Memória Imunológica , Linfonodos/citologia , Linfonodos/imunologia , Macaca mulatta , Subpopulações de Linfócitos T/imunologia , Transcrição Gênica , Transcriptoma/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA