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1.
bioRxiv ; 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38712046

RESUMO

Interleukin 2 (IL-2) is the first identified cytokine and its interaction with receptors has been known to shape the immune responses in many lymphoid or non-lymphoid tissues for more than four decades. Active T cells are the primary cellular source for IL-2 production and epithelial cells have never been considered the major cellular source of IL-2 under physiological conditions. It is, however, tempting to speculate that epithelial cells could potentially express IL-2 that regulates the intricate interactions between epithelial cells and lymphocytes. Datamining our recently published single-cell RNAseq in the mouse mammary gland identified IL-2 expression in mammary epithelial cells, which is induced by prolactin via the STAT5 signaling pathway. Furthermore, epithelial IL-2 plays a crucial role in maintaining the physiological functions of natural killer (NK) cells within the mammary glands. IL-2 deletion in the mammary epithelial cells leads to a significant reduction in the number and function of NK cells, which in turn results in defective immunosurveillance, expansion of luminal epithelial cells, and tumor development. Interestingly, T cells in the mammary glands are not changed, indicating the specific regulation of NK cells by epithelial IL-2 production. In agreement, we also found that human epithelial cells express IL-2 and NK cells express the highest level of IL2RB among all the immune cells. Here, we provide the first evidence that epithelial cells produce IL-2, which is critical for maintaining the physiological functions of NK cells in immunosurveillance.

2.
J Interpers Violence ; 38(23-24): 12089-12112, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37602736

RESUMO

Using the context of an intimate partner homicide trial, the study explored the effects of defendant gender and age on mock-jurors' verdicts, sentences, and culpability ratings-and whether defendant credibility and juror anger mediate these effects. The study used a 2 (Defendant Gender: male vs. female) × 3 (Defendant Age: 25, 45, or 65 years) between-subjects design. Participants (N = 513 community members) completed the experiment online. Participants were randomly assigned to one of the six Defendant Gender × Age Conditions. Participants read the trial transcripts that included the age and gender manipulations, provided verdicts and sentences, and completed the following measures: culpability, anger, credibility, and manipulation checks. Consistent with our hypotheses mock-jurors were more likely to find the male defendant guilty and give him longer sentences than the female defendant. Additionally, when the defendant was male (vs. female) mock-jurors provided higher anger ratings and rated the defendant as more culpable in the victim's death. Also consistent with our hypotheses, mock-jurors were more likely to find the youngest defendant guilty and view him as more culpable and less credible than the oldest defendant. The mechanisms responsible for jurors' biased decisions varied as a function of the extra-legal variable (defendant gender vs. age). The defendant age effect was mediated by defendant credibility and the gender effect by juror anger. A defendant's right to a fair trial is dependent on a court's ability to limit extra-legal variables from influencing jurors' decisions. Understanding the mechanism responsible for such bias is required before the courts can effectively remedy bias.


Assuntos
Culpa , Homicídio , Feminino , Humanos , Masculino , Ira , Direito Penal , Tomada de Decisões , Julgamento , Função Jurisdicional , Adulto , Pessoa de Meia-Idade , Idoso
3.
J Neurochem ; 164(4): 499-511, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36336816

RESUMO

Obesity is one of the leading health concerns in the United States. Studies from human and rodent models suggest that inherent differences in the function of brain motivation centers, including the nucleus accumbens (NAc), contribute to overeating and thus obesity. For example, there are basal enhancements in the excitability of NAc GABAergic medium spiny neurons (MSN) and reductions in basal expression of AMPA-type glutamate receptors in obesity-prone vs obesity-resistant rats. However, very little is known about the regulation of extracellular glutamate and GABA within the NAc of these models. Here we gave obesity-prone and obesity-resistant rats stable isotope-labeled glucose (13 C6 -glucose) and used liquid chromatography mass spectrometry (LC-MS) analysis of NAc dialysate to examine the real-time incorporation of 13 C6 -glucose into glutamate, glutamine, and GABA. This novel approach allowed us to identify differences in glucose utilization for neurotransmitter production between these selectively bred lines. We found that voluntarily ingested or gastrically infused 13 C6 -glucose rapidly enters the NAc and is incorporated into 13 C2 -glutamine, 13 C2 -glutamate, and 13 C2 -GABA in both groups within minutes. However, the magnitude of increases in NAc 13 C2 -glutamine and 13 C2 -GABA were lower in obesity-prone than in obesity-resistant rats, while basal levels of glutamate were elevated. This suggested that there may be differences in the astrocytic regulation of these analytes. Thus, we next examined NAc glutamine synthetase, GAD67, and GLT-1 protein expression. Consistent with reduced 13 C2 -glutamine and 13 C2 -GABA, NAc glutamine synthetase and GLT-1 protein expression were reduced in obesity-prone vs obesity-resistant groups. Taken together, these data show that NAc glucose utilization differs dramatically between obesity-prone and obesity-resistant rats, favoring glutamate over GABA production in obesity-prone rats and that reductions in NAc astrocytic recycling of glutamate contribute to these differences. These data are discussed in light of established differences in NAc function between these models and the role of the NAc in feeding behavior.


Assuntos
Ácido Glutâmico , Núcleo Accumbens , Humanos , Ratos , Animais , Ácido Glutâmico/metabolismo , Núcleo Accumbens/metabolismo , Glutamina/metabolismo , Glutamato-Amônia Ligase/metabolismo , Obesidade/metabolismo , Ácido gama-Aminobutírico/metabolismo , Glucose/metabolismo
4.
Delirium Commun ; 20232023.
Artigo em Inglês | MEDLINE | ID: mdl-38361911

RESUMO

Background: Since 2015, the American Delirium Society (ADS) Research Committee has conducted an annual survey of the delirium literature for presentation in its year-in-review session. Our objectives were to describe the review process used for the 2021-2022 and to summarise the selected publications. Methods: Each member of the ADS Research Committee nominated up to 6 publications considered to be the most impactful primary delirium research published from September 1, 2021, to July 31, 2022. The 24 nominated studies were divided into three categories balanced by number of articles: medical intervention trials, non-medical intervention trials, and delirium detection/basic science studies. Each ADS Research Committee member ranked all studies in their assigned category for methodological rigor and for impact, each being scored as 0-10, for a total score of 0-20. It was decided a priori to select the top three highest-scoring articles in each category for presentation, with ties adjudicated by Committee consensus. Results: Nineteen Research Committee members served as reviewers. Scores for each category were similar: medical interventions mean (standard deviation) 12.8 (1.1), non-medical interventions 13.1 (1.1), and detection/basic science 12.6 (1.0). We summarise the results of the papers presented in the 2022 ADS year-in-review session. Conclusion: The diversity of studies presented for the 2022 ADS year-in-review session illustrates the breadth of the delirium field and the growing number of clinical trials. The dissemination of publications across a broad, diverse array of journals provides further justification of the need for delirium-specific journals.

5.
Nature ; 610(7930): 173-181, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36171288

RESUMO

Combination therapy with PD-1 blockade and IL-2 is highly effective during chronic lymphocytic choriomeningitis virus infection1. Here we examine the underlying basis for this synergy. We show that PD-1 + IL-2 combination therapy, in contrast to PD-1 monotherapy, substantially changes the differentiation program of the PD-1+TCF1+ stem-like CD8+ T cells and results in the generation of transcriptionally and epigenetically distinct effector CD8+ T cells that resemble highly functional effector CD8+ T cells seen after an acute viral infection. The generation of these qualitatively superior CD8+ T cells that mediate viral control underlies the synergy between PD-1 and IL-2. Our results show that the PD-1+TCF1+ stem-like CD8+ T cells, also referred to as precursors of exhausted CD8+ T cells, are not fate-locked into the exhaustion program and their differentiation trajectory can be changed by IL-2 signals. These virus-specific effector CD8+ T cells emerging from the stem-like CD8+ T cells after combination therapy expressed increased levels of the high-affinity IL-2 trimeric (CD25-CD122-CD132) receptor. This was not seen after PD-1 blockade alone. Finally, we show that CD25 engagement with IL-2 has an important role in the observed synergy between IL-2 cytokine and PD-1 blockade. Either blocking CD25 with an antibody or using a mutated version of IL-2 that does not bind to CD25 but still binds to CD122 and CD132 almost completely abrogated the synergistic effects observed after PD-1 + IL-2 combination therapy. There is considerable interest in PD-1 + IL-2 combination therapy for patients with cancer2,3, and our fundamental studies defining the underlying mechanisms of how IL-2 synergizes with PD-1 blockade should inform these human translational studies.


Assuntos
Linfócitos T CD8-Positivos , Interleucina-2 , Receptor de Morte Celular Programada 1 , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/efeitos dos fármacos , Quimioterapia Combinada , Humanos , Subunidade gama Comum de Receptores de Interleucina , Interleucina-2/imunologia , Interleucina-2/farmacologia , Interleucina-2/uso terapêutico , Subunidade alfa de Receptor de Interleucina-2 , Subunidade beta de Receptor de Interleucina-2 , Coriomeningite Linfocítica/tratamento farmacológico , Coriomeningite Linfocítica/imunologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Fator 1 de Transcrição de Linfócitos T
6.
Cell Rep ; 39(2): 110632, 2022 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-35417685

RESUMO

Differential interleukin-2 (IL-2) signaling and production are associated with disparate effector and memory fates. Whether the IL-2 signals perceived by CD8 T cells come from autocrine or paracrine sources, the timing of IL-2 signaling and their differential impact on CD8 T cell responses remain unclear. Using distinct models of germline and conditional IL-2 ablation in post-thymic CD8 T cells, this study shows that paracrine IL-2 is sufficient to drive optimal primary expansion, effector and memory differentiation, and metabolic function. In contrast, autocrine IL-2 is uniquely required during primary expansion to program robust secondary expansion potential in memory-fated cells. This study further shows that IL-2 production by antigen-specific CD8 T cells is largely independent of CD4 licensing of dendritic cells (DCs) in inflammatory infections with robust DC activation. These findings bear implications for immunizations and adoptive T cell immunotherapies, where effector and memory functions may be commandeered through IL-2 programming.


Assuntos
Memória Imunológica , Interleucina-2 , Animais , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular , Interleucina-2/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
7.
Ann Med Surg (Lond) ; 71: 102925, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34691448

RESUMO

INTRODUCTION: There is a dearth of data about the benefits of local anesthesia (LA) and spinal anesthesia (SA) compared to general anesthesia (GA) in patients undergoing repair of recurrent groin (inguinal/femoral) hernias. We hypothesized that patients with recurrent hernias who undergo repair under LA and SA will have a better outcome. METHODS AND PROCEDURES: Using the 2017 American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP)® database, patients who underwent open repair of recurrent groin hernias were identified and divided into three groups: GA, SA, and LA. Outcomes evaluated included 30-day mortality and morbidity, operative time, total hospital length of stay (LOS), and reoperation and readmission rates. RESULTS: A total of 2169 patients were identified of which 1847 (85.2%) were in GA, 53 (2.4%) in SA, and 269 (12.4%) in LA groups. Overall, no statistically significant differences in demographics and comorbidities between the three groups were identified. However, patients in GA were younger and healthier with lower ASA Class (I-II) as compared to SA and LA groups. Patients in SA had a higher rate of COPD, and their overall operative time was shorter. However, LA patients had shorter LOS, and most LA patients were discharged home on the same day compared to GA, SA (92.2% vs. 77.9%, and 73.6%, p < 0.001). No differences in 30-day mortality and morbidity or reoperation and readmission rates between the three groups were noted. CONCLUSION: There is an underutilization of LA in patients undergoing open repair of recurrent inguinal hernia despite favorable outcomes, even in high-risk patients, when compared to GA and SA. Further prospective studies are needed to explore the potential barriers and cost-effectiveness of implementing LA as a primary anesthetic technique in inguinal hernia repair.

8.
Forensic Sci Med Pathol ; 17(4): 706-710, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34449015

RESUMO

A 3-year-old white female with no significant past medical history was found unresponsive and apneic after several hours of vomiting. The patient had reportedly felt unwell since jumping in a bounce house at a festival earlier in the day. After one hour of attempted resuscitation by EMS and hospital staff, the patient was pronounced deceased. On autopsy there was a 3 cm opening in the left posterolateral hemidiaphragm with the spleen, the stomach, and portions of the small and large bowel displaced into the left chest cavity, resulting in compression of both lungs and the heart to the right side of the chest. The right lung weighed 295 g while the left lung weighed 73 g. Histologic examination revealed atelectasis in the left lung and congestion in the right lung, the spleen, the stomach, and the bowel. The cause of death was ultimately ruled to be respiratory compromise and associated gastrointestinal complications due to diaphragmatic herniation of abdominal contents into the chest cavity. It is hypothesized that herniation occurred in this case secondary to increased intra-abdominal pressure from jumping in a bounce house, an etiology that we were unable to find elsewhere despite a thorough literature search.


Assuntos
Hérnias Diafragmáticas Congênitas , Autopsia , Pré-Escolar , Morte Súbita/etiologia , Diafragma , Feminino , Humanos , Pulmão
9.
Integr Med (Encinitas) ; 19(5): 16-28, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33488302

RESUMO

BACKGROUND: Obesity is a complex multifactorial disorder affecting a growing proportion of the population. While therapeutic lifestyle change (TLC) is foundational, results of interventional programs are often inconsistent. Factors related to systemic inflammation, toxin load and endotoxemia have been postulated to play a contributory role. This pilot study sought to evaluate the role of TLC with enhanced laboratory evaluation and interventions to address these emerging therapeutic targets. METHODS: Twelve participants with a body mass index (BMI) greater than 30 (or 27 with metabolic co-morbidities) were recruited from an outpatient clinic for participation with a primary outcome of pre/post changes in body composition. Participants completed a 12-week program involving weekly group and individualized dietary, exercise, and behavioral support, supplemented with a commercial, 30-day dietary detoxification intervention and ongoing nutritional counseling. All participants completed baseline and post-intervention evaluation including metabolic, toxin load, endotoxin, body composition and functional fitness profiles. RESULTS: After 12-weeks, participants as a group significantly improved body composition parameters including BMI, body fat, fat mass, and waist and hip circumference (P < .01). Significant improvement in several secondary outcomes including levels of lipopolysaccharide, zonulin and leptin were noted. Additionally, results demonstrate substantial improvements in pain, pain interference and functional fitness. Upon completion, all participants rated the program favorably with a high likelihood of continuing or recommending participation to others. CONCLUSIONS: Obesity remains a challenging and often refractory clinical scenario with emerging evidence indicating the potential role of systemic inflammation, toxin load and endotoxemia. A group therapeutic lifestyle change program enhanced with a detoxification component is feasible and may provide a promising intervention for achieving weight loss while also addressing functional and pain related co-morbidities. Future randomized trials evaluating the components of such a program are needed to better delineate the role of specific interventions in the complex setting of obesity.

10.
Nature ; 568(7752): 405-409, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30944470

RESUMO

Interleukin (IL)-2 is a pleiotropic cytokine that is necessary to prevent chronic inflammation in the gastrointestinal tract1-4. The protective effects of IL-2 involve the generation, maintenance and function of regulatory T (Treg) cells4-8, and the use of low doses of IL-2 has emerged as a potential therapeutic strategy for patients with inflammatory bowel disease9. However, the cellular and molecular pathways that control the production of IL-2 in the context of intestinal health are undefined. Here we show, in a mouse model, that IL-2 is acutely required to maintain Treg cells and immunological homeostasis throughout the gastrointestinal tract. Notably, lineage-specific deletion of IL-2 in T cells did not reduce Treg cells in the small intestine. Unbiased analyses revealed that, in the small intestine, group-3 innate lymphoid cells (ILC3s) are the dominant cellular source of IL-2, which is induced selectively by IL-1ß. Macrophages in the small intestine produce IL-1ß, and activation of this pathway involves MYD88- and NOD2-dependent sensing of the microbiota. Our loss-of-function studies show that ILC3-derived IL-2 is essential for maintaining Treg cells, immunological homeostasis and oral tolerance to dietary antigens in the small intestine. Furthermore, production of IL-2 by ILC3s was significantly reduced in the small intestine of patients with Crohn's disease, and this correlated with lower frequencies of Treg cells. Our results reveal a previously unappreciated pathway in which a microbiota- and IL-1ß-dependent axis promotes the production of IL-2 by ILC3s to orchestrate immune regulation in the intestine.


Assuntos
Imunidade Inata/imunologia , Interleucina-2/imunologia , Intestinos/citologia , Intestinos/imunologia , Linfócitos T Reguladores/imunologia , Animais , Antígenos/administração & dosagem , Antígenos/imunologia , Doença de Crohn/imunologia , Doença de Crohn/metabolismo , Doença de Crohn/patologia , Feminino , Microbioma Gastrointestinal/imunologia , Homeostase/imunologia , Humanos , Inflamação/imunologia , Inflamação/patologia , Interleucina-1beta/imunologia , Interleucina-1beta/metabolismo , Interleucina-2/deficiência , Interleucina-2/metabolismo , Intestino Delgado/citologia , Intestino Delgado/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Fator 88 de Diferenciação Mieloide/deficiência , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , Proteína Adaptadora de Sinalização NOD2/deficiência , Proteína Adaptadora de Sinalização NOD2/genética , Proteína Adaptadora de Sinalização NOD2/metabolismo , Linfócitos T Reguladores/classificação , Linfócitos T Reguladores/metabolismo
11.
J Immunol ; 200(12): 3926-3933, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29728511

RESUMO

The cytokine IL-2 is critical for promoting the development, homeostasis, and function of regulatory T (Treg) cells. The cellular sources of IL-2 that promote these processes remain unclear. T cells, B cells, and dendritic cells (DCs) are known to make IL-2 in peripheral tissues. We found that T cells and DCs in the thymus also make IL-2. To identify cellular sources of IL-2 in Treg cell development and homeostasis, we used Il2FL/FL mice to selectively delete Il2 in T cells, B cells, and DCs. Because IL-15 can partially substitute for IL-2 in Treg cell development, we carried out the majority of these studies on an Il15-/- background. Deletion of Il2 in B cells, DCs, or both these subsets had no effect on Treg cell development, either in wild-type (WT) or Il15-/- mice. Deletion of Il2 in T cells had minimal effects in WT mice but virtually eliminated developing Treg cells in Il15-/- mice. In the spleen and most peripheral lymphoid organs, deletion of Il2 in B cells, DCs, or both subsets had no effect on Treg cell homeostasis. In contrast, deletion of Il2 in T cells led to a significant decrease in Treg cells in either WT or Il15-/- mice. The one exception was the mesenteric lymph nodes where significantly fewer Treg cells were observed when Il2 was deleted in both T cells and DCs. Thus, T cells are the sole source of IL-2 needed for Treg cell development, but DCs can contribute to Treg cell homeostasis in select organs.


Assuntos
Homeostase/imunologia , Interleucina-2/imunologia , Linfócitos T Reguladores/imunologia , Animais , Linfócitos B/imunologia , Células Dendríticas/imunologia , Linfonodos/imunologia , Linfócitos/imunologia , Camundongos , Baço/imunologia
13.
Neurobiol Dis ; 86: 154-69, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26611103

RESUMO

HIV-associated neurocognitive disorders (HAND) still occur in approximately 50% of HIV patients, and therapies to combat HAND progression are urgently needed. HIV proteins are released from infected cells and cause neuronal damage, possibly through mitochondrial abnormalities. Altered mitochondrial fission and fusion is implicated in several neurodegenerative disorders. Here, we hypothesized that mitochondrial fission/fusion may be dysregulated in neurons during HAND. We have identified decreased mitochondrial fission protein (dynamin 1-like; DNM1L) in frontal cortex tissues of HAND donors, along with enlarged and elongated mitochondria localized to the soma of damaged neurons. Similar pathology was observed in the brains of GFAP-gp120 tg mice. In vitro, recombinant gp120 decreased total and active DNM1L levels, reduced the level of Mitotracker staining, and increased extracellular acidification rate (ECAR) in primary neurons. DNM1L knockdown enhanced the effects of gp120 as measured by reduced Mitotracker signal in the treated cells. Interestingly, overexpression of DNM1L increased the level of Mitotracker staining in primary rat neurons and reduced neuroinflammation and neurodegeneration in the GFAP-gp120-tg mice. These data suggest that mitochondrial biogenesis dynamics are shifted towards mitochondrial fusion in brains of HAND patients and this may be due to gp120-induced reduction in DNM1L activity. Promoting mitochondrial fission during HIV infection of the CNS may restore mitochondrial biogenesis and prevent neurodegeneration.


Assuntos
Encéfalo/metabolismo , Transtornos Cognitivos/metabolismo , Transtornos Cognitivos/virologia , Infecções por HIV/complicações , Mitocôndrias/metabolismo , Dinâmica Mitocondrial , Neurônios/metabolismo , Adulto , Animais , Encéfalo/ultraestrutura , Encéfalo/virologia , Dinaminas , Encefalite/metabolismo , Encefalite/virologia , Feminino , Lobo Frontal/metabolismo , Lobo Frontal/ultraestrutura , Lobo Frontal/virologia , GTP Fosfo-Hidrolases/metabolismo , Proteína gp120 do Envelope de HIV/metabolismo , Humanos , Masculino , Camundongos , Proteínas Associadas aos Microtúbulos/metabolismo , Pessoa de Meia-Idade , Mitocôndrias/ultraestrutura , Mitocôndrias/virologia , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas Mitocondriais/metabolismo , Neurônios/ultraestrutura , Neurônios/virologia , Ratos , Ratos Sprague-Dawley , Células Tumorais Cultivadas
14.
Front Immunol ; 6: 502, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26483792
16.
Sci Rep ; 5: 14166, 2015 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-26391053

RESUMO

Mechanically robust battery electrodes are desired for applications in wearable devices, flexible displays, and structural energy and power. In this regard, the challenge is to balance mechanical and electrochemical properties in materials that are inherently brittle. Here, we demonstrate a unique water-based self-assembly approach that incorporates a diblock copolymer bearing electron- and ion-conducting blocks, poly(3-hexylthiophene)-block-poly(ethyleneoxide) (P3HT-b-PEO), with V2O5 to form a flexible, tough, carbon-free hybrid battery cathode. V2O5 is a promising lithium intercalation material, but it remains limited by its poor conductivity and mechanical properties. Our approach leads to a unique electrode structure consisting of interlocking V2O5 layers glued together with micellar aggregates of P3HT-b-PEO, which results in robust mechanical properties, far exceeding the those obtained from conventional fluoropolymer binders. Only 5 wt % polymer is required to triple the flexibility of V2O5, and electrodes comprised of 10 wt % polymer have unusually high toughness (293 kJ/m(3)) and specific energy (530 Wh/kg), both higher than reduced graphene oxide paper electrodes. Furthermore, addition of P3HT-b-PEO enhances lithium-ion diffusion, eliminates cracking during cycling, and boosts cyclability relative to V2O5 alone. These results highlight the importance of tradeoffs between mechanical and electrochemical performance, where polymer content can be used to tune both aspects.


Assuntos
Fontes de Energia Elétrica , Eletrodos , Polímeros , Compostos de Vanádio
18.
Front Immunol ; 5: 356, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25120542
20.
Front Immunol ; 5: 29, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24550914

RESUMO

Early reports on T cell antigen receptor (TCR) signaling uncovered a rapid increase in intracellular calcium concentration and the activation of calcium-dependent protein kinase as necessary for T cell activation. Cytolytic T cell clones were instrumental in the discovery of intracellular cytolytic granules, and the isolation of the perforin and granzyme molecules as the molecular effectors of cell-mediated lysis of target cells via apoptosis. Cytolytic T cell clones and TCR cDNA clones were also instrumental for the generation of TCR transgenic animals, which provided definitive evidence for negative selection of self-reactive immature thymocytes. In addition, studies of TCR complex signaling of immature thymocytes compared with mature T cells were consistent with the interpretation that negative selection occurs as a consequence of the incapacity of immature cells to produce IL-2, resulting in cytokine deprivation apoptosis. By comparison, taking advantage of cloned TCRs derived from T cell clones reactive with male-specific molecules, using TCR transgenic mice it was possible to document positive selection of female thymocytes when the male-specific molecules were absent. Focusing on the molecular mechanisms of T cell "help" for the generation of antibody-forming cells following the path opened by the elucidation of the IL-2 molecule, several groups were successful in the identification, isolation, and characterization of three new interleukin molecules (IL-4, IL-5, and IL-6) that promote the proliferation and differentiation of B cells. In addition, the identification of a B cell surface molecule (CD40) that augmented B cell antigen receptor-stimulated proliferation and differentiation led to the discovery of a T cell activation surface molecule that proved to be the CD40-ligand, thus finally providing a molecular explanation for "linked or cognate" recognition when T cells and B cells interact physically. Accordingly, the decade after the generation of the first T cell clones saw the elucidation of the molecular mechanisms of T cell cytotoxicity and T cell help, thereby expanding the number of molecules responsible for adaptive T cell immunity.

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