RESUMO
Tumor cell proliferation requires sufficient metabolic flux through the pentose phosphate pathway to meet the demand for biosynthetic precursors and to increase protection against oxidative stress which in turn requires an upregulation of substrate flow through glycolysis. This metabolic poise is often coupled with a shift in ATP production from mitochondrial OXPHOS to substrate-level phosphorylation. Despite major advances that were facilitated by using tumor-derived cell lines in research areas spanning from membrane to cytoskeletal biology, this distorted metabolic profile limits their impact as a model in physiology and toxicology. Substitution of glucose with galactose in the cell culture medium has been demonstrated to shift ATP production from substrate-level phosphorylation to mitochondrial OXPHOS. This increase in oxygen utilization is coupled to a global metabolic reorganization with potential impacts on macromolecule biosynthesis and cellular redox homeostasis, but a comprehensive analysis on the effects of sugar substitution in tumor-derived cells is still missing. To address this gap in knowledge we performed transcriptomic and metabolomic analyses on human hepatocellular carcinoma (HepG2) cells adapted to either glucose or galactose as the aldohexose source. We observed a shift toward oxidative metabolism in all primary metabolic pathways at both transcriptomic and metabolomic levels. We also observed a decrease in nicotinamide dinucleotide (NAD(P)) levels and subcellular NAD+-to-NADH ratios in cells cultured with galactose compared with glucose control cells. Our results suggest that galactose reduces both glycolytic and biosynthetic flux and restores a metabolic poise in HepG2 cells that closely reflects the metabolic state observed in primary hepatocytes.
Assuntos
Carcinoma Hepatocelular/metabolismo , Proliferação de Células/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Galactose/farmacologia , Hepatócitos/efeitos dos fármacos , Neoplasias Hepáticas/metabolismo , Mitocôndrias Hepáticas/efeitos dos fármacos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Metabolismo Energético/genética , Regulação Neoplásica da Expressão Gênica , Glucose/farmacologia , Células Hep G2 , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Metaboloma , Mitocôndrias Hepáticas/metabolismo , Mitocôndrias Hepáticas/patologia , Oxirredução , Fenótipo , Fatores de Tempo , TranscriptomaRESUMO
Spectral lines are among the most powerful signatures for dark matter (DM) annihilation searches in very-high-energy γ rays. The central region of the Milky Way halo is one of the most promising targets given its large amount of DM and proximity to Earth. We report on a search for a monoenergetic spectral line from self-annihilations of DM particles in the energy range from 300 GeV to 70 TeV using a two-dimensional maximum likelihood method taking advantage of both the spectral and spatial features of the signal versus background. The analysis makes use of Galactic center observations accumulated over ten years (2004-2014) with the H.E.S.S. array of ground-based Cherenkov telescopes. No significant γ-ray excess above the background is found. We derive upper limits on the annihilation cross section ⟨σv⟩ for monoenergetic DM lines at the level of 4×10^{-28} cm^{3} s^{-1} at 1 TeV, assuming an Einasto DM profile for the Milky Way halo. For a DM mass of 1 TeV, they improve over the previous ones by a factor of 6. The present constraints are the strongest obtained so far for DM particles in the mass range 300 GeV-70 TeV. Ground-based γ-ray observations have reached sufficient sensitivity to explore relevant velocity-averaged cross sections for DM annihilation into two γ-ray photons at the level expected from the thermal relic density for TeV DM particles.
RESUMO
A search for dark matter linelike signals iss performed in the vicinity of the Galactic Center by the H.E.S.S. experiment on observational data taken in 2014. An unbinned likelihood analysis iss developed to improve the sensitivity to linelike signals. The upgraded analysis along with newer data extend the energy coverage of the previous measurement down to 100 GeV. The 18 h of data collected with the H.E.S.S. array allow one to rule out at 95% C.L. the presence of a 130 GeV line (at l=-1.5°, b=0° and for a dark matter profile centered at this location) previously reported in Fermi-LAT data. This new analysis overlaps significantly in energy with previous Fermi-LAT and H.E.S.S. RESULTS: No significant excess associated with dark matter annihilations was found in the energy range of 100 GeV to 2 TeV and upper limits on the gamma-ray flux and the velocity weighted annihilation cross section are derived adopting an Einasto dark matter halo profile. Expected limits for present and future large statistics H.E.S.S. observations are also given.
RESUMO
The inner region of the Milky Way halo harbors a large amount of dark matter (DM). Given its proximity, it is one of the most promising targets to look for DM. We report on a search for the annihilations of DM particles using γ-ray observations towards the inner 300 pc of the Milky Way, with the H.E.S.S. array of ground-based Cherenkov telescopes. The analysis is based on a 2D maximum likelihood method using Galactic Center (GC) data accumulated by H.E.S.S. over the last 10 years (2004-2014), and does not show any significant γ-ray signal above background. Assuming Einasto and Navarro-Frenk-White DM density profiles at the GC, we derive upper limits on the annihilation cross section ⟨σv⟩. These constraints are the strongest obtained so far in the TeV DM mass range and improve upon previous limits by a factor 5. For the Einasto profile, the constraints reach ⟨σv⟩ values of 6×10^{-26} cm^{3} s^{-1} in the W^{+}W^{-} channel for a DM particle mass of 1.5 TeV, and 2×10^{-26} cm^{3} s^{-1} in the τ^{+}τ^{-} channel for a 1 TeV mass. For the first time, ground-based γ-ray observations have reached sufficient sensitivity to probe ⟨σv⟩ values expected from the thermal relic density for TeV DM particles.
RESUMO
An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated on-off observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of â¼9 h of on-off observations. Upper limits on the velocity averaged cross section, ⟨σv⟩, for the annihilation of dark matter particles with masses in the range of â¼300 GeV to â¼10 TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of ⟨σv⟩ that are larger than 3×10^{-24} cm^{3}/s are excluded for dark matter particles with masses between â¼1 and â¼4 TeV at 95% C.L. if the radius of the central dark matter density core does not exceed 500 pc. This is the strongest constraint that is derived on ⟨σv⟩ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region.
RESUMO
Diarrhoeal management practices are unsatisfactory in India especially in the slum areas. Dearth of information regarding physicians' diarrhoea-related knowledge and practice in India necessitated this cross-sectional study of allopathic practitioners in the slums of Kolkata, to assess the distribution and interrelationship between physicians' characteristics, knowledge and practice regarding diarrhoea. A total of 264 randomly selected consenting practitioners were interviewed using a field-tested questionnaire. Nineteen percent had good overall knowledge, 49% and 80% prescribed antibiotics to diarrhoea and cholera patients, respectively, and 55% advised stool examination for every case. Qualified and Government physicians had better knowledge regarding diarrhoea [MBBS: odds ratio (OR) 5·96, P < 0·001; postgraduates: OR 9·33, P < 0·001; Government physicians: OR 11·49, P < 0·0001] and were less likely to prescribe antibiotics for all diarrhoea cases (MBBS: OR 0·30, P = 0·002; postgraduates: OR 0·20, P < 0·001; Government physicians OR 0·24, P < 0·029). Better knowledge was associated with a lower likelihood of prescribing antibiotics for diarrhoea (OR 0·72, P < 0·001), cholera (OR 0·78, P = 0·027) and investigative procedure (OR 0·85, P = 0·028). In the slums of Kolkata, diarrhoea-related knowledge and practice were poor with the exception of qualified physicians, hence an improvement in the knowledge of pharmacists and unqualified practitioners is necessary for the overall improvement of diarrhoeal management in these slums.
Assuntos
Competência Clínica/estatística & dados numéricos , Diarreia/terapia , Áreas de Pobreza , Padrões de Prática Médica/estatística & dados numéricos , Antibacterianos/uso terapêutico , Competência Clínica/normas , Diarreia/tratamento farmacológico , Diarreia/prevenção & controle , Feminino , Humanos , Índia/epidemiologia , Entrevistas como Assunto , Masculino , Padrões de Prática Médica/normas , Fatores Socioeconômicos , Inquéritos e Questionários , População Urbana/estatística & dados numéricosRESUMO
The current article presents a huge enhancement in the field emission characteristics of zinc oxide (ZnO) micro/nanorods by nickel doping. The synthesis of pure and nickel-doped zinc oxide (ZnO) micro/nanorods was done by a simple low-temperature chemical method. Both the as-prepared pure and doped samples were analyzed by X-ray diffraction and electron microscopy to confirm the proper phase formation and the developed microstructure. UV-vis transmittance spectra helped in determining the band gap of the samples. Fourier-Transform Infrared Spectroscopy (FTIR) spectra showed the different bonds present in the sample, whereas X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of nickel in the doped sample. Photoluminescence (PL) spectra showed that after doping, the band-to-band transition was affected, whereas defect-induced transition had increased significantly. After the nickel doping, contact angle measurement revealed a significant decrease in the sample's surface energy, leading to a remarkably high water contact angle (within the superhydrophobic region). Simulation through ANSYS suggested that the doped sample has the potential to function as an efficient cold emitter, which was also verified experimentally. The cold emission characteristics of the doped sample showed a significant improvement, with the turn-on field (corresponding to J = 1 µA cm-2) reduced from 5.34 to 2.84 V µm-1. The enhancement factor for the doped sample reached 3426, approximately 1.5 times higher compared to pure ZnO. Efforts have been made to explain the results, given the favorable band bending as well as the increased number of effective emission sites.
RESUMO
T cell-mediated immune response against autologous melanoma cells was analyzed, at population and clonal levels, in 31 patients with recurrent and/or metastatic disease. Fresh PBL and lymph node lymphocytes (LNL) from melanoma-involved nodes were not cytotoxic against the respective melanoma cells. When activated in in vitro coculture (IVC) against the autologous melanoma cells in the presence of IL-2, a majority of the activated PBL and LNL became cytotoxic against the autologous targets. The activated effector cells were cloned in limiting dilution microcultures, and growing clones were phenotypically defined and were functionally characterized for cytotoxicity and for potential regulatory function. Functional T cell clones were obtained from 15 of 31 cases. Of these, CTL responses exhibiting cytotoxicity restricted against the autologous melanoma were seen in four cases. All four CTL clones were CD3+, CD8+, and CD4-. Three of these four CTL clones were studied extensively. All three of these CTL clones expressed MHC class I-restricted cytotoxicity. mAb anti-CD3 blocked cytotoxicity in two and enhanced cytotoxicity in the other. Neither autologous sera nor autologous nonactivated fresh PBL modulated the cytotoxic functions of the CTL clones at the effector phase. T cell lines exhibiting regulatory function were obtained in 11 cases. The regulatory T cell lines were CD3+, CD4+, and CD8-. In three cases CD4+ clones amplified the cytotoxic response in the PBL in coculture, while in eight other cases the T cell lines downregulated the cytotoxic responses. Such T cell-mediated down-regulations were either restricted to the autologous system, induced by D/DR antigens expressed by the autologous or allogeneic melanoma cells, or induced by stimulus other than D/DR antigens. Taken together, these findings clearly demonstrate the existence of T cell-mediated cytotoxic and regulatory responses against human melanoma.
Assuntos
Células Clonais/imunologia , Testes Imunológicos de Citotoxicidade , Melanoma/imunologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T/imunologia , Antígenos de Neoplasias/imunologia , Linhagem Celular , Sobrevivência Celular , Células Clonais/fisiologia , Testes Imunológicos de Citotoxicidade/métodos , Citotoxicidade Imunológica , Epitopos/imunologia , Humanos , Interferon gama/fisiologia , Interleucina-2/fisiologia , Antígenos Específicos de Melanoma , Proteínas de Neoplasias/imunologia , Linfócitos T/fisiologia , Linfócitos T Citotóxicos/fisiologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Reguladores/imunologiaRESUMO
MATE genes play an important role in cellular detoxification processes. Nine MATE genes were identified by a transcriptomics study previously. Candidate gene prioritization was done where 29 new genes were found to interact with 09 guide genes. Therefore, a total of 38 genes were analyzed here to predict a concise model by gene prioritization study. Those genes were analyzed further in Rice Interactions Viewer programme, and based on high ICV, 10 new genes were found to interact among themselves at protein level. Surprisingly, only 05 genes were found to play a key role at protein level. These 15 genes were analyzed for their interaction with soil available inorganic arsenic species. Maximum expression levels were found mostly at young inflorescence and seed development stage for those genes. So, these genes may have a direct role in arsenic sequestration from cells and thereby providing safety to the developing embryo within the seed.
RESUMO
BACKGROUND AND AIMS: Dysarthria affects linguistic domains such as respiration, phonation, articulation, resonance and prosody due to upper motor neuron, lower motor neuron, cerebellar or extrapyramidal tract lesions. Although Bengali is one of the major languages globally, dysarthric Bengali speech has not been subjected to neurolinguistic analysis. We attempted such an analysis with the goal of identifying the speech defects in native Bengali speakers in various types of dysarthria encountered in neurological disorders. SETTINGS AND DESIGN: A cross-sectional observational study was conducted with 66 dysarthric subjects, predominantly middle-aged males, attending the Neuromedicine OPD of a tertiary care teaching hospital in Kolkata. MATERIALS AND METHODS: After neurological examination, an instrument comprising commonly used Bengali words and a text block covering all Bengali vowels and consonants were used to carry out perceptual analysis of dysarthric speech. From recorded speech, 24 parameters pertaining to five linguistic domains were assessed. The Kruskal-Wallis analysis of variance, Chi-square test and Fisher's exact test were used for analysis. RESULTS: The dysarthria types were spastic (15 subjects), flaccid (10), mixed (12), hypokinetic (12), hyperkinetic (9) and ataxic (8). Of the 24 parameters assessed, 15 were found to occur in one or more types with a prevalence of at least 25%. Imprecise consonant was the most frequently occurring defect in most dysarthrias. The spectrum of defects in each type was identified. Some parameters were capable of distinguishing between types. CONCLUSIONS: This perceptual analysis has defined linguistic defects likely to be encountered in dysarthric Bengali speech in neurological disorders. The speech distortion can be described and distinguished by a limited number of parameters. This may be of importance to the speech therapist and neurologist in planning rehabilitation and further management.
Assuntos
Disartria/etiologia , Testes de Articulação da Fala , Percepção da Fala , Adolescente , Adulto , Idoso , Análise de Variância , Criança , Estudos Transversais , Disartria/classificação , Disartria/epidemiologia , Feminino , Humanos , Índia/epidemiologia , Linguística , Masculino , Pessoa de Meia-Idade , Exame Neurológico , Variações Dependentes do ObservadorRESUMO
The present work aims at modeling the entire convection flux ρuW¯ in the transport equation for a mean reaction rate ρW¯ in a turbulent flow, which (equation) was recently put forward by the present authors. In order to model the flux, several simple closure relations are developed by introducing flow velocity conditioned to reaction zone and interpolating this velocity between two limit expressions suggested for the leading and trailing edges of the mean flame brush. Subsequently, the proposed simple closure relations for ρuW¯ are assessed by processing two sets of data obtained in earlier 3D Direct Numerical Simulation (DNS) studies of adiabatic, statistically planar, turbulent, premixed, single-step-chemistry flames characterized by unity Lewis number. One dataset consists of three cases characterized by different density ratios and is associated with the flamelet regime of premixed turbulent combustion. Another dataset consists of four cases characterized by different low Damköhler and large Karlovitz numbers. Accordingly, this dataset is associated with the thin reaction zone regime of premixed turbulent combustion. Under conditions of the former DNS, difference in the entire, ρuW¯ , and mean, uρW¯ , convection fluxes is well pronounced, with the turbulent flux, ρu''W''¯ , showing countergradient behavior in a large part of the mean flame brush. Accordingly, the gradient diffusion closure of the turbulent flux is not valid under such conditions, but some proposed simple closure relations allow us to predict the entire flux ρuW¯ reasonably well. Under conditions of the latter DNS, the difference in the entire and mean convection fluxes is less pronounced, with the aforementioned simple closure relations still resulting in sufficiently good agreement with the DNS data.
RESUMO
Community-based rehabilitation is the strategy endorsed by the World Health Organization and other international bodies to promote the inclusion of people with disabilities, particularly in low- and middle-income countries. In this article we trace the journey of Edawu, a mental health rehabilitation unit in a rural area of Benue State, Nigeria, from an in-patient rehabilitation unit to a community-focused service. The partnership of organisations from the UK with Edawu along the journey is also described. The authors set out learning points from the project and the principles behind sustainable overseas organisational partnerships.
RESUMO
A social-stress mouse model was used to simulate features of post-traumatic stress disorder (PTSD). The model involved exposure of an intruder (male C57BL/6) mouse to a resident aggressor (male SJL) mouse for 5 or 10 consecutive days. Transcriptome changes in brain regions (hippocampus, amygdala, medial prefrontal cortex and hemibrain), blood and spleen as well as epigenome changes in the hemibrain were assayed after 1- and 10-day intervals following the 5-day trauma or after 1- and 42-day intervals following the 10-day trauma. Analyses of differentially expressed genes (common among brain, blood and spleen) and differentially methylated promoter regions revealed that neurogenesis and synaptic plasticity pathways were activated during the early responses but were inhibited after the later post-trauma intervals. However, inflammatory pathways were activated throughout the observation periods, except in the amygdala in which they were inhibited only at the later post-trauma intervals. Phenotypically, inhibition of neurogenesis was corroborated by impaired Y-maze behavioral responses. Sustained neuroinflammation appears to drive the development and maintenance of behavioral manifestations of PTSD, potentially via its inhibitory effect on neurogenesis and synaptic plasticity. By contrast, peripheral inflammation seems to be directly responsible for tissue damage underpinning somatic comorbid pathologies. Identification of overlapping, differentially regulated genes and pathways between blood and brain suggests that blood could be a useful and accessible brain surrogate specimen for clinical translation.
Assuntos
Inflamação/metabolismo , Transtornos de Estresse Pós-Traumáticos/genética , Tonsila do Cerebelo/metabolismo , Animais , Sintomas Comportamentais/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Hipocampo/metabolismo , Inflamação/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurogênese/genética , Neurogênese/fisiologia , Plasticidade Neuronal/genética , Plasticidade Neuronal/fisiologia , Córtex Pré-Frontal/metabolismo , Estresse Psicológico/metabolismo , Transcriptoma/genéticaRESUMO
Emerging knowledge suggests that post-traumatic stress disorder (PTSD) pathophysiology is linked to the patients' epigenetic changes, but comprehensive studies examining genome-wide methylation have not been performed. In this study, we examined genome-wide DNA methylation in peripheral whole blood in combat veterans with and without PTSD to ascertain differentially methylated probes. Discovery was initially made in a training sample comprising 48 male Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF) veterans with PTSD and 51 age/ethnicity/gender-matched combat-exposed PTSD-negative controls. Agilent whole-genome array detected ~5600 differentially methylated CpG islands (CpGI) annotated to ~2800 differently methylated genes (DMGs). The majority (84.5%) of these CpGIs were hypermethylated in the PTSD cases. Functional analysis was performed using the DMGs encoding the promoter-bound CpGIs to identify networks related to PTSD. The identified networks were further validated by an independent test set comprising 31 PTSD+/29 PTSD- veterans. Targeted bisulfite sequencing was also used to confirm the methylation status of 20 DMGs shown to be highly perturbed in the training set. To improve the statistical power and mitigate the assay bias and batch effects, a union set combining both training and test set was assayed using a different platform from Illumina. The pathways curated from this analysis confirmed 65% of the pool of pathways mined from training and test sets. The results highlight the importance of assay methodology and use of independent samples for discovery and validation of differentially methylated genes mined from whole blood. Nonetheless, the current study demonstrates that several important epigenetically altered networks may distinguish combat-exposed veterans with and without PTSD.
Assuntos
Metilação de DNA , Transtornos de Estresse Pós-Traumáticos/genética , Adulto , Campanha Afegã de 2001- , Ilhas de CpG , Epigênese Genética , Humanos , Guerra do Iraque 2003-2011 , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Veteranos , Saúde dos Veteranos , Adulto JovemRESUMO
The existence of CD8+ CTLs that are capable of recognizing MHC class I-bound, human tumor-associated peptide antigens is now unequivocally documented in cancer patients. Thus far, the role of CD8+ T cells in tumor immunity has been predominantly viewed in terms of cytolytic ability as the prime mode of their function. Interestingly, it is increasingly evident that CD8+ T cells are capable of synthesizing both type I and type II cytokines. Thus, it is conceivable that tumor antigen-specific but noncytolytic CD8+ T cells might play an important role in antitumor immune response by synthesizing type I cytokine. Through such cytokines, they could provide "help" for the process of generating as well as in maintaining an effective CD8+ CTL response. In addition, they might recruit other types of effector cells (such as natural killer cells, macrophages, and others) locally at the tumor site. Either way, they could exert a profoundly positive role in cell-mediated antitumor immune response, particularly because the great majority of tumor cells express only MHC class I molecules that present peptide epitopes to CD8+ T cells. Unfortunately, tumor antigen-specific, noncytolytic but type I cytokine-secreting CD8+ T cells have not received much investigative attention. Here we show that CD8+ T cells, isolated from the tumor-infiltrating lymphocytes from human melanoma, synthesize type I cytokine (IFN-gamma and tumor necrosis factor alpha) in a MHC class I-restricted and tumor-specific noncytolytic interaction with the autologous melanoma cells.
Assuntos
Antígenos de Neoplasias/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Citocinas/biossíntese , Melanoma/imunologia , Proteínas de Neoplasias/imunologia , Células Th1/metabolismo , Humanos , Interleucina-1/farmacologia , Linfonodos/patologia , Antígenos Específicos de Melanoma , Sensibilidade e Especificidade , Células Tumorais CultivadasRESUMO
Both CD8+ and CD4+ T cells have demonstrated roles in antitumor immune response in many animal tumor systems. In many human tumor systems, although abundant literature exists on the evidence of tumor antigen-specific CD8+ CTL response, only limited information is available on tumor antigen-specific CD4+ T-cell response. Using the MART-1/Melan-A (MART-1) antigen system as a prototype human tumor-associated antigen (TAA)- and dendritic cell (DC)-based MART-1 antigen presentation system (i.e., DCs transduced with an adenoviral vector-based construct carrying the MART-1 gene), we explored, in vitro, the feasibility of generating both CD8+ and CD4+ T-cell responses in the same individual. Here, we show that autologous DCs from both HLA-A2-positive melanoma patients and normal healthy individuals that are transduced with an adenoviral vector containing the MART-1 antigen are capable of inducing both MART-1-specific CD8+ and CD4+ T cells in in vitro coculture. After several rounds of stimulation, both the CD4+ and CD8+ T cells synthesized IFN-gamma when they were specifically stimulated. The CD8+ T cells generated in such cocultures also recognized the MART-1(27-35) peptide, AAGIGILTV, in 4-h cytotoxicity assays. These observations, therefore, suggest that Th1-type responses can be generated, in vitro, by stimulation with DCs that are genetically modified to express a TAA. Although the outcome of this type of genetically engineered DC-based stimulation may vary from system to system, this type of in vitro antigen presentation may be very useful in more comprehensive analyses of CD4+ T-cell response to defined TAAs, and such genetically engineered autologous DCs might be better candidates to serve as surrogate cancer vaccines.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/imunologia , Proteínas de Neoplasias/imunologia , Antígenos de Neoplasias , Comunicação Celular/fisiologia , Células Dendríticas/metabolismo , Células Dendríticas/fisiologia , Epitopos/imunologia , Epitopos de Linfócito T/imunologia , Humanos , Ativação Linfocitária/fisiologia , Antígeno MART-1 , Melanoma/imunologia , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Transdução GenéticaRESUMO
Identification of human melanoma-associated peptide antigens for CTLs has opened unprecedented opportunities for active specific immunotherapy for melanoma with synthetic peptide. We have shown that immunization with a MAGE-1 gene encoded nonapeptide (EADPT-GHSY)-pulsed autologous antigen presenting cell-based vaccine induces autologous melanoma-reactive and peptide-specific CTL response, in situ, at the vaccination site and at distant tumor deposits in patients who are HLA-A1+ and whose melanoma cells express the MAGE-1 mRNA. Here, we show that such immunization is also capable of increasing the frequency of autologous melanoma-reactive CTL precursors in the circulation. We further show that in vitro stimulation of the postimmunization peripheral blood lymphocytes with the MAGE-1 nonapeptide-loaded antigen presenting cell and interleukin-2 leads to significant expansion of peptide-specific and autologous melanoma-reactive CTL response.
Assuntos
Antígenos de Neoplasias/imunologia , Melanoma/imunologia , Proteínas de Neoplasias , Linfócitos T Citotóxicos/imunologia , Sequência de Aminoácidos , Células Apresentadoras de Antígenos/imunologia , Citotoxicidade Imunológica , Humanos , Imunização , Antígenos Específicos de Melanoma , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/imunologia , Fator de Necrose Tumoral alfa/biossíntese , Vacinas/imunologiaRESUMO
Twelve autologous mixed peripheral blood (PBL) tumor cell interactions (MLTC) followed by in vitro expansion of the stimulated T cells in recombinant interleukin-2 (IL-2) were analyzed for the potential emergence of oligoclonal or monoclonal T cell populations in the PBL by Southern blot analysis of the T cell receptor (TCR) beta gene. The emergence of oligoclonal or monoclonal TCR beta gene rearranged populations was seen in 5 of the 12 cases. In 2 of these 5 cases only one dominantly rearranged band was observed. The emergence of oligoclonal or monoclonal T cell populations following stimulation with autologous melanoma cells was associated with predominant CD4 phenotype of the stimulated PBL exhibiting a varied degree of cytotoxicity toward the respective autologous melanoma cells. The evidence of emergence of monoclonal or oligoclonal T cell populations following stimulation with autologous tumor cells strongly supports the existence of T cell-mediated responses against autologous melanomas. Furthermore, cellular and molecular analyses of T cell responses in autologous mixed lymphocyte tumor cell interactions will provide valuable information on the nature of the T cell responses and on the pattern of gene segment usages by the T cells in response to the autologous tumor cells.
Assuntos
Rearranjo Gênico da Cadeia beta dos Receptores de Antígenos dos Linfócitos T , Interleucina-2/farmacologia , Melanoma/imunologia , Receptores de Antígenos de Linfócitos T/genética , Subpopulações de Linfócitos T/patologia , Antígenos de Diferenciação de Linfócitos T/análise , Antígenos CD4/análise , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/patologia , Antígenos CD8 , Células Clonais/efeitos dos fármacos , Humanos , Teste de Cultura Mista de Linfócitos , Melanoma/patologia , Receptores de Antígenos de Linfócitos T alfa-beta , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologiaRESUMO
Autologous peripheral blood stem cell transplantation following myeloablative chemotherapy is being increasingly utilized in the treatment of a variety of malignancies. We administered busulfan 16 mg/kg orally, thiotepa 500-700 mg/m2 i.v., and carboplatin 800-1000 mg/m2 i.v. to 56 women with metastatic carcinoma of the breast. Autologous peripheral blood stem cells, which had been collected after a combination of chemotherapy and granulocyte colony-stimulating factor, were infused on day 0. The major toxicities of the conditioning regimen included severe pancytopenia, stomatitis, nausea, emesis, diarrhea, fever, and infection. Transplant-related mortality was 1.8%. The incidence of opportunistic viral infections was 42.9%. Fourteen individuals achieved a complete response. The actuarial survival at 1223 days was 13.7% for the entire group of patients; the actuarial survival at 1009 days was 39.3% among complete responders. The functional status of the immune system was determined following transplantation in a subset of patients. Peripheral blood mononuclear cells were obtained before and after stem cell infusion, and were analyzed phenotypically and functionally. Proliferative and interleukin-2 synthetic ability of these cells was assessed following stimulation with phytohemagglutinin and anti-CD3 antibody. The response to influenza peptides was also ascertained. Proliferative and interleukin-2 synthetic capacity was markedly impaired for over a year. Memory response was virtually absent for up to 2 years following transplantation. The prolonged and marked immunosuppression following this myeloablative regimen was associated with a high incidence of opportunistic viral infections, and may have contributed to disease relapse and progression especially in patients who failed to achieve a complete response following transplantation.