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1.
Science ; 382(6676): 1270-1276, 2023 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-38096385

RESUMO

Current HIV vaccines designed to stimulate CD8+ T cells have failed to induce immunologic control upon infection. The functions of vaccine-induced HIV-specific CD8+ T cells were investigated here in detail. Cytotoxic capacity was significantly lower than in HIV controllers and was not a consequence of low frequency or unaccumulated functional cytotoxic proteins. Low cytotoxic capacity was attributable to impaired degranulation in response to the low antigen levels present on HIV-infected targets. The vaccine-induced T cell receptor (TCR) repertoire was polyclonal and transduction of these TCRs conferred the same reduced functions. These results define a mechanism accounting for poor antiviral activity induced by these vaccines and suggest that an effective CD8+ T cell response may require a vaccination strategy that drives further TCR clonal selection.


Assuntos
Vacinas contra a AIDS , Degranulação Celular , Citotoxicidade Imunológica , Infecções por HIV , Linfócitos T Citotóxicos , Humanos , Vacinas contra a AIDS/imunologia , Células Clonais , Infecções por HIV/prevenção & controle , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T Citotóxicos/imunologia , Degranulação Celular/imunologia
2.
Cell ; 186(10): 2111-2126.e20, 2023 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-37172564

RESUMO

Microglia are specialized brain-resident macrophages that play crucial roles in brain development, homeostasis, and disease. However, until now, the ability to model interactions between the human brain environment and microglia has been severely limited. To overcome these limitations, we developed an in vivo xenotransplantation approach that allows us to study functionally mature human microglia (hMGs) that operate within a physiologically relevant, vascularized immunocompetent human brain organoid (iHBO) model. Our data show that organoid-resident hMGs gain human-specific transcriptomic signatures that closely resemble their in vivo counterparts. In vivo two-photon imaging reveals that hMGs actively engage in surveilling the human brain environment, react to local injuries, and respond to systemic inflammatory cues. Finally, we demonstrate that the transplanted iHBOs developed here offer the unprecedented opportunity to study functional human microglia phenotypes in health and disease and provide experimental evidence for a brain-environment-induced immune response in a patient-specific model of autism with macrocephaly.


Assuntos
Microglia , Organoides , Humanos , Encéfalo , Macrófagos , Fenótipo
4.
Appl Opt ; 62(6): A25-A30, 2023 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-36821296

RESUMO

Krypton Tagging Velocimetry (KTV) and Picosecond Laser Electronic Excitation Tagging (PLEET) velocimetry at a 100-kHz rate were demonstrated in Mach 18 flow conditions at the Arnold Engineering Development Center (AEDC) Tunnel 9 employing a burst-mode laser system and a custom optical parametric oscillator (OPO). The measured freestream flow velocities from both KTV and PLEET agreed well with the theoretical calculation. The increase in repetition rate provides better capability to perform time-resolved velocimetry measurements in hypersonic flow environments.

5.
Ann Pharmacother ; 57(5): 513-520, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-35993253

RESUMO

BACKGROUND: Insulin remains a mainstay of treating hyperglycemia in an acute setting. Insulin glargine 300 units/mL (Toujeo, iGlar300) has a different pharmacokinetic profile than 100 units/mL basal insulins, such as insulin detemir (iDet100) and iGlar100. While conversion from iGlar300 to iGlar100 requires a 20% dose decrease, there is currently no recommended interchange from iGlar300 to iDet100. OBJECTIVE: Compare the incidence of hypoglycemia in patients who received a 1:1 unit interchange from home iGlar300 or iGlar100 to iDet100 while admitted. METHODS: A retrospective study was conducted to evaluate adults within a multi-site network admitted between May and December 2019. Patients were included if they received at least one dose of iDet100 following interchange from home iGlar300 or iGlar100. The primary endpoint was the incidence of hypoglycemic events following a 1:1 interchange of iGlar300 vs. iGlar100 to inpatient iDet100. Secondary outcomes include overall hypoglycemic events, time to hypoglycemia, and doses given before hypoglycemia. RESULTS: Of 615 patients, 394 received a 1:1 unit interchange to iDet100 (52 from iGlar300 and 342 from iGlar100). Incidence of hypoglycemic events was significantly higher in those with a 1:1 interchange from iGlar300 versus iGlar100 (36.5% vs. 18.7%, p = 0.007). Significant differences were observed in overall hypoglycemic events, time to hypoglycemia, and number of doses given before hypoglycemic event. CONCLUSION AND RELEVANCE: A 1:1 unit interchange from iGlar300 to iDet100 led to a higher incidence of hypoglycemic events compared to those interchanged from iGlar100. Dose reduction should be considered when transitioning from home iGlar300 to iDet100 in the inpatient setting.


Assuntos
Diabetes Mellitus Tipo 2 , Hipoglicemia , Adulto , Humanos , Insulina Glargina/efeitos adversos , Insulina Detemir/efeitos adversos , Pacientes Internados , Estudos Retrospectivos , Insulina de Ação Prolongada/efeitos adversos , Glicemia , Hipoglicemia/induzido quimicamente , Hipoglicemia/epidemiologia , Hipoglicemia/tratamento farmacológico , Hipoglicemiantes/efeitos adversos , Insulina/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia
6.
medRxiv ; 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38168429

RESUMO

Accurate forecasts can enable more effective public health responses during seasonal influenza epidemics. Forecasting teams were asked to provide national and jurisdiction-specific probabilistic predictions of weekly confirmed influenza hospital admissions for one through four weeks ahead for the 2021-22 and 2022-23 influenza seasons. Across both seasons, 26 teams submitted forecasts, with the submitting teams varying between seasons. Forecast skill was evaluated using the Weighted Interval Score (WIS), relative WIS, and coverage. Six out of 23 models outperformed the baseline model across forecast weeks and locations in 2021-22 and 12 out of 18 models in 2022-23. Averaging across all forecast targets, the FluSight ensemble was the 2nd most accurate model measured by WIS in 2021-22 and the 5th most accurate in the 2022-23 season. Forecast skill and 95% coverage for the FluSight ensemble and most component models degraded over longer forecast horizons and during periods of rapid change. Current influenza forecasting efforts help inform situational awareness, but research is needed to address limitations, including decreased performance during periods of changing epidemic dynamics.

7.
J Chem Phys ; 157(16): 164105, 2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36319404

RESUMO

We present a means of studying rare reactive pathways in open quantum systems using transition path theory and ensembles of quantum jump trajectories. This approach allows for the elucidation of reactive paths for dissipative, nonadiabatic dynamics when the system is embedded in a Markovian environment. We detail the dominant pathways and rates of thermally activated processes and the relaxation pathways and photoyields following vertical excitation in a minimal model of a conical intersection. We find that the geometry of the conical intersection affects the electronic character of the transition state as defined through a generalization of a committor function for a thermal barrier crossing event. Similarly, the geometry changes the mechanism of relaxation following a vertical excitation. Relaxation in models resulting from small diabatic coupling proceeds through pathways dominated by pure dephasing, while those with large diabatic coupling proceed through pathways limited by dissipation. The perspective introduced here for the nonadiabatic dynamics of open quantum systems generalizes classical notions of reactive paths to fundamentally quantum mechanical processes.

8.
J Clin Transl Sci ; 6(1): e110, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36285024

RESUMO

Background: Diversity, equity, and inclusion (DEI) in clinical and translational science (CTS) are paramount to driving innovation and increasing health equity. One important area for improving diversity is among trainees in CTS programs. This paper reports on findings from a special session at the November 2020 Clinical and Translational Science Award (CTSA) national program meeting that focused on advancing diversity and inclusion within CTS training programs. Methods: Using qualitative content analysis, we identified approaches brought forth to increase DEI in KL2 career development and other training programs aimed at early-stage CTS investigators, beyond the six strategies put forth to guide the breakout session (prioritizing representation, building partnerships, making it personal, designing program structure, improving through feedback, and winning endorsement). We used an inductive qualitative content analysis approach to identify themes from a transcript of the panel of KL2 program leaders centered on DEI in training programs. Results: We identified four themes for advancing DEI within CTS training programs: 1) institutional buy-in; 2) proactive recruitment efforts; 3) an equitable application process; and 4) high-quality, diverse mentorship. Conclusion: Implementing these strategies in CTS and other training programs will be an important step for advancing DEI. However, processes need to be established to evaluate the implementation and effectiveness of these strategies through continuous quality improvement, a key component of the CTSA program. Training programs within the CTSA are well-positioned to be leaders in this critical effort to increase the diversity of the scientific workforce.

9.
Nature ; 604(7907): 689-696, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35444276

RESUMO

The structure of the human neocortex underlies species-specific traits and reflects intricate developmental programs. Here we sought to reconstruct processes that occur during early development by sampling adult human tissues. We analysed neocortical clones in a post-mortem human brain through a comprehensive assessment of brain somatic mosaicism, acting as neutral lineage recorders1,2. We combined the sampling of 25 distinct anatomic locations with deep whole-genome sequencing in a neurotypical deceased individual and confirmed results with 5 samples collected from each of three additional donors. We identified 259 bona fide mosaic variants from the index case, then deconvolved distinct geographical, cell-type and clade organizations across the brain and other organs. We found that clones derived after the accumulation of 90-200 progenitors in the cerebral cortex tended to respect the midline axis, well before the anterior-posterior or ventral-dorsal axes, representing a secondary hierarchy following the overall patterning of forebrain and hindbrain domains. Clones across neocortically derived cells were consistent with a dual origin from both dorsal and ventral cellular populations, similar to rodents, whereas the microglia lineage appeared distinct from other resident brain cells. Our data provide a comprehensive analysis of brain somatic mosaicism across the neocortex and demonstrate cellular origins and progenitor distribution patterns within the human brain.


Assuntos
Células Clonais , Mosaicismo , Neocórtex , Linhagem da Célula , Células Cultivadas , Humanos , Microglia , Neocórtex/citologia , Neocórtex/crescimento & desenvolvimento
10.
Cell Rep ; 38(10): 110489, 2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35263587

RESUMO

Monosodium urate crystals (MSUc) induce inflammation in vivo without prior priming, raising the possibility of an initial cell-autonomous phase. Here, using genome-wide transcriptomic analysis and biochemical assays, we demonstrate that MSUc alone induce a metabolic-inflammatory transcriptional program in non-primed human and murine macrophages that is markedly distinct to that induced by LPS. Genes uniquely upregulated in response to MSUc belong to lipid and amino acid metabolism, glycolysis, and SLC transporters. This upregulation leads to a metabolic rewiring in sera from individuals and mice with acute gouty arthritis. Mechanistically, the initiating inflammatory-metabolic changes in acute gout flares are regulated through a persistent expression and increased binding of JUN to the promoter of target genes through JNK signaling-but not P38-in a process that is different than after LPS stimulation and independent of inflammasome activation. Finally, pharmacological JNK inhibition limits MSUc-induced inflammation in animal models of acute gouty inflammation.


Assuntos
Artrite Gotosa , Ácido Úrico , Animais , Artrite Gotosa/induzido quimicamente , Artrite Gotosa/metabolismo , Inflamação/metabolismo , Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Camundongos , Ácido Úrico/metabolismo
11.
J Am Coll Clin Pharm ; 4(12): 1516-1523, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34901761

RESUMO

INTRODUCTION: Heart failure hospitalization is a hallmark of disease progression associated with increased morbidity and mortality. Benefits of multidisciplinary clinics have been established in the care of heart failure patients and can be particularly impactful post-hospital discharge. OBJECTIVE: This study aimed to investigate the impact of a clinical pharmacist-integrated model of care within a Heart Failure Bridge Clinic (HFBC) at a large tertiary care referral center. METHODS: In this single-center retrospective study, patients with left ventricular ejection fraction (LVEF) ≤40% discharged from Mission Hospital (Asheville, North Carolina) between August 2018 and July 2019 were screened. Patients in the HFBC arm had a clinic visit inclusive of a clinical pharmacist within 30 days of hospital discharge and were compared with a control group of patients with a usual care provider clinic visit. The HFBC provided clinical assessment, detailed heart failure education, and medication reconciliation and adjustment with an emphasis on optimization of Guideline Directed Medical Therapy (GDMT). Patients were followed for 90 days for the primary end point of hospitalization, emergency department (ED) visit, or death. RESULTS: A total of 1463 patients (HFBC, n = 307; control, n = 1156) comprised our final cohort. After accounting for baseline variables, 90-day cumulative probability of hospitalization, ED visit, or death favored HFBC patients (26% vs 32%, P = .0275). Comprehensive review of medications prior to and after HFBC appointment demonstrated significant alterations to therapies (30% GDMT addition, 27% GDMT titration, 7.2% discontinuation of medications associated with worsening heart failure, and 28% loop diuretic adjustment). CONCLUSION: Clinical pharmacist-integrated HFBC allows for focused medication review and optimization and is associated with a 19% relative risk reduction in hospitalization, ED visit, or death at 90 days.

12.
Proc Natl Acad Sci U S A ; 118(51)2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34903655

RESUMO

Short-term forecasts of traditional streams from public health reporting (such as cases, hospitalizations, and deaths) are a key input to public health decision-making during a pandemic. Since early 2020, our research group has worked with data partners to collect, curate, and make publicly available numerous real-time COVID-19 indicators, providing multiple views of pandemic activity in the United States. This paper studies the utility of five such indicators-derived from deidentified medical insurance claims, self-reported symptoms from online surveys, and COVID-related Google search activity-from a forecasting perspective. For each indicator, we ask whether its inclusion in an autoregressive (AR) model leads to improved predictive accuracy relative to the same model excluding it. Such an AR model, without external features, is already competitive with many top COVID-19 forecasting models in use today. Our analysis reveals that 1) inclusion of each of these five indicators improves on the overall predictive accuracy of the AR model; 2) predictive gains are in general most pronounced during times in which COVID cases are trending in "flat" or "down" directions; and 3) one indicator, based on Google searches, seems to be particularly helpful during "up" trends.


Assuntos
COVID-19/epidemiologia , Indicadores Básicos de Saúde , Modelos Estatísticos , Métodos Epidemiológicos , Previsões , Humanos , Internet/estatística & dados numéricos , Inquéritos e Questionários , Estados Unidos/epidemiologia
13.
Proc Natl Acad Sci U S A ; 118(51)2021 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-34903654

RESUMO

The COVID-19 pandemic presented enormous data challenges in the United States. Policy makers, epidemiological modelers, and health researchers all require up-to-date data on the pandemic and relevant public behavior, ideally at fine spatial and temporal resolution. The COVIDcast API is our attempt to fill this need: Operational since April 2020, it provides open access to both traditional public health surveillance signals (cases, deaths, and hospitalizations) and many auxiliary indicators of COVID-19 activity, such as signals extracted from deidentified medical claims data, massive online surveys, cell phone mobility data, and internet search trends. These are available at a fine geographic resolution (mostly at the county level) and are updated daily. The COVIDcast API also tracks all revisions to historical data, allowing modelers to account for the frequent revisions and backfill that are common for many public health data sources. All of the data are available in a common format through the API and accompanying R and Python software packages. This paper describes the data sources and signals, and provides examples demonstrating that the auxiliary signals in the COVIDcast API present information relevant to tracking COVID activity, augmenting traditional public health reporting and empowering research and decision-making.


Assuntos
COVID-19/epidemiologia , Bases de Dados Factuais , Indicadores Básicos de Saúde , Assistência Ambulatorial/tendências , Métodos Epidemiológicos , Humanos , Internet/estatística & dados numéricos , Distanciamento Físico , Inquéritos e Questionários , Viagem , Estados Unidos/epidemiologia
15.
J Chem Phys ; 155(5): 054201, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34364357

RESUMO

We introduce a heterodimer model in which multiple mechanisms of vibronic coupling and their impact on energy transfer can be explicitly studied. We consider vibronic coupling that arises through either Franck-Condon activity in which each site in the heterodimer has a local electron-phonon coupling or Herzberg-Teller activity in which the transition dipole moment coupling the sites has an explicit vibrational mode-dependence. We have computed two-dimensional electronic-vibrational (2DEV) spectra for this model while varying the magnitude of these two effects and find that 2DEV spectra contain static and dynamic signatures of both types of vibronic coupling. Franck-Condon activity emerges through a change in the observed excitonic structure, while Herzberg-Teller activity is evident in the appearance of significant side-band transitions that mimic the lower-energy excitonic structure. A comparison of quantum beating patterns obtained from analysis of the simulated 2DEV spectra shows that this technique can report on the mechanism of energy transfer, elucidating a means of experimentally determining the role of specific vibronic coupling mechanisms in such processes.

16.
Sci Rep ; 11(1): 10527, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006911

RESUMO

Kokumi taste is a well-accepted and characterised taste modality and is described as a sensation of enhancement of sweet, salty, and umami tastes. The Calcium Sensing Receptor (CaSR) has been designated as the putative kokumi taste receptor for humans, and a number of kokumi-active ligands of CaSR have been discovered recently with activity confirmed both in vivo and in vitro. Domestic cats (Felis catus) are obligate carnivores and accordingly, their diet is abundant in proteins, peptides, and amino acids. We hypothesised that CaSR is a key taste receptor for carnivores, due to its role in the detection of different peptides and amino acids in other species. Using in silico, in vitro and in vivo approaches, here we compare human CaSR to that of a model carnivore, the domestic cat. We found broad similarities in ligand specificity, but differences in taste sensitivity between the two species. Indeed our in vivo data shows that cats are sensitive to CaCl2 as a kokumi compound, but don't show this same activity with Glutathione, whereas for humans the reverse is true. Collectively, our data suggest that kokumi is an important taste modality for carnivores that drives the palatability of meat-derived compounds such as amino acids and peptides, and that there are differences in the perception of kokumi taste between carnivores and omnivores.


Assuntos
Gatos/fisiologia , Percepção Gustatória , Sequência de Aminoácidos , Aminoácidos/análise , Animais , Cloreto de Cálcio/metabolismo , Glutationa/metabolismo , Humanos , Ligantes , Cloreto de Magnésio/metabolismo , Produtos da Carne/análise , Peptídeos/análise , Ligação Proteica , Receptores de Detecção de Cálcio/metabolismo , Papilas Gustativas/metabolismo
17.
Science ; 372(6537): 91-94, 2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33795458

RESUMO

Neurons are the longest-lived cells in our bodies and lack DNA replication, which makes them reliant on a limited repertoire of DNA repair mechanisms to maintain genome fidelity. These repair mechanisms decline with age, but we have limited knowledge of how genome instability emerges and what strategies neurons and other long-lived cells may have evolved to protect their genomes over the human life span. A targeted sequencing approach in human embryonic stem cell-induced neurons shows that, in neurons, DNA repair is enriched at well-defined hotspots that protect essential genes. These hotspots are enriched with histone H2A isoforms and RNA binding proteins and are associated with evolutionarily conserved elements of the human genome. These findings provide a basis for understanding genome integrity as it relates to aging and disease in the nervous system.


Assuntos
Reparo do DNA , Genoma Humano , Instabilidade Genômica , Neurônios/metabolismo , Envelhecimento/genética , Dano ao DNA , DNA Intergênico , Desoxiuridina/análogos & derivados , Desoxiuridina/metabolismo , Células-Tronco Embrionárias , Histonas/metabolismo , Humanos , Mitose , Mutação , Doenças do Sistema Nervoso/genética , Neurônios/citologia , Regiões Promotoras Genéticas , Proteínas de Ligação a RNA/metabolismo , Análise de Sequência de DNA , Transcrição Gênica
18.
Neural Regen Res ; 16(9): 1711-1714, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33510059

RESUMO

The contribution of chronic peripheral inflammation to the pathogenesis of neurodegenerative diseases is an outstanding question. Sustained activation of the peripheral innate and adaptive immune systems occurs in the context of a broad array of disorders ranging from chronic infectious diseases to autoimmune and metabolic diseases. In addition, progressive systemic inflammation is increasingly recognized during aging. Peripheral immune cells could potentially modulate the cellular brain environment via the secretion of soluble molecules. There is an ongoing debate whether peripheral immune cells have the potential to migrate into the brain under certain permissive circumstances. In this perspective, we discuss the possible contribution of chronic peripheral inflammation to the pathogenesis of age-related neurodegenerative diseases with a focus on microglia, the resident immune cells of the brain parenchyma.

19.
Open Forum Infect Dis ; 8(1): ofaa613, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33511235

RESUMO

BACKGROUND: Possible human immunodeficiency virus (HIV)-1 clearance has rarely been reported. In this study, we describe a unique case of an HIV-positive, combination antiretroviral therapy (cART)-experienced woman with prior acquired immunodeficiency syndrome (AIDS) who has not experienced viral rebound for over 12 years since discontinuing cART. METHODS: Leukapheresis, colonoscopy, and lymph node excision were performed for detailed examination of virologic (including HIV reservoir) and immunologic features. Comparisons were made with chronically infected patients and healthy controls. RESULTS: No HIV-specific antibodies were detected in serum. Plasma HIV ribonucleic acid (RNA) levels were <0.2 copies/mL, and, except for low-frequency HIV deoxyribonucleic acid (DNA)+ cells in lymph node tissue (1 copy/3 × 106 cells), HIV antigen could not be detected by quantitative virus outgrowth (<0.0025 infectious units/106 CD4+ T cells) or by most measurements of HIV RNA or DNA in blood, lymph node, or gut-associated mononuclear cells. Human immunodeficiency virus-specific T-cell responses were detectable but low. Brain imaging revealed a prior biopsy site and persistent white matter disease since 1996. Human immunodeficiency virus DNA+ cells in the 1996 brain biopsy specimen confirmed her identity and initial HIV diagnosis. CONCLUSIONS: This represents the first report of complete seroreversion, prolonged posttreatment virus suppression, a profoundly small HIV reservoir, and persistent HIV-specific T cells in an adult with prior AIDS.

20.
J Virol ; 94(23)2020 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-32907983

RESUMO

In various infections or vaccinations of mice or humans, reports of the persistence and the requirements for restimulation of the cytotoxic mediators granzyme B (GrB) and perforin (PRF) in CD8+ T cells have yielded disparate results. In this study, we examined the kinetics of PRF and GrB mRNA and protein expression after stimulation and associated changes in cytotoxic capacity in virus-specific memory cells in detail. In patients with controlled HIV or cleared respiratory syncytial virus (RSV) or influenza virus infections, all virus-specific CD8+ T cells expressed low PRF levels without restimulation. Following stimulation, they displayed similarly delayed kinetics for lytic protein expression, with significant increases occurring by days 1 to 3 before peaking on days 4 to 6. These increases were strongly correlated with, but were not dependent upon, proliferation. Incremental changes in PRF and GrB percent expression and mean fluorescence intensity (MFI) were highly correlated with increases in HIV-specific cytotoxicity. mRNA levels in HIV-specific CD8+ T-cells exhibited delayed kinetics after stimulation as with protein expression, peaking on day 5. In contrast to GrB, PRF mRNA transcripts were little changed over 5 days of stimulation (94-fold versus 2.8-fold, respectively), consistent with posttranscriptional regulation. Changes in expression of some microRNAs, including miR-17, miR-150, and miR-155, suggested that microRNAs might play a significant role in regulation of PRF expression. Therefore, under conditions of extremely low or absent antigen levels, memory virus-specific CD8+ T cells require prolonged stimulation over days to achieve maximal lytic protein expression and cytotoxic capacity.IMPORTANCE Antigen-specific CD8+ T cells play a major role in controlling most virus infections, primarily by perforin (PRF)- and granzyme B (GrB)-mediated apoptosis. There is considerable controversy regarding whether PRF is constitutively expressed, rapidly increased similarly to a cytokine, or delayed in its expression with more prolonged stimulation in virus-specific memory CD8+ T cells. In this study, the degree of cytotoxic capacity of virus-specific memory CD8+ T cells was directly proportional to the content of lytic molecules, which required antigenic stimulation over several days for maximal levels. This appeared to be modulated by increases in GrB transcription and microRNA-mediated posttranscriptional regulation of PRF expression. Clarifying the requirements for maximal cytotoxic capacity is critical to understanding how viral clearance might be mediated by memory cells and what functions should be induced by vaccines and immunotherapies.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Infecções por HIV/imunologia , Animais , Antígenos CD8/metabolismo , Granzimas/metabolismo , HIV/metabolismo , Infecções por HIV/metabolismo , Humanos , Cinética , Camundongos , MicroRNAs , Perforina , RNA Mensageiro/metabolismo
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