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Printed Electronics has emerged as an important fabrication technique that overcomes several shortcomings of conventional lithography and provides custom rapid prototyping for various sensor applications. In this work, silver microelectrode arrays (MEA) with three different electrode spacing were fabricated using 3-D printing by the aerosol jet technology. The microelectrodes were printed at a length scale of about 15 µm, with the space between the electrodes accurately controlled to about 2 times (30 µm, MEA30), 6.6 times (100 µm, MEA100) and 12 times (180 µm, MEA180) the trace width, respectively. Hydrogen peroxide and glucose were chosen as model analytes to demonstrate the performance of the MEA for sensor applications. The electrodes are shown to reduce hydrogen peroxide with a reduction current proportional to the concentration of hydrogen peroxide for certain concentration ranges. Further, the sensitivity of the current for the three electrode configurations was shown to decrease with an increase in the microelectrode spacing (sensitivity of MEA30: MEA100: MEA180 was in the ratio of 3.7: 2.8: 1), demonstrating optimal MEA geometry for such applications. The noise of the different electrode configurations is also characterized and shows a dramatic reduction from MEA30 to MEA100 and MEA180 electrodes. Further, it is shown that the response current is proportional to MEA100 and MEA180 electrode areas, but not for the area of MEA30 electrode (the current density of MEA30 : MEA100 : MEA180 is 0.25 : 1 : 1), indicating that the MEA30 electrodes suffer from diffusion overlap from neighboring electrodes. The work thus establishes the lower limit of microelectrode spacing for our geometry. The lowest detection limit of the MEAs was calculated (with S/N = 3) to be 0.45 µM. Glucose oxidase was immobilized on MEA100 microelectrodes to demonstrate a glucose biosensor application. The sensitivity of glucose biosensor was 1.73 µAmM-1 and the calculated value of detection limit (S/N = 3) was 1.7 µM. The electrochemical response characteristics of the MEAs were in agreement with the predictions of existing models. The current work opens up the possibility of additive manufacturing as a fabrication technique for low cost custom-shaped MEA structures that can be used as electrochemical platforms for a wide range of sensor applications.
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Every nation treasures its handloom heritage, and in India, the handloom industry safeguards cultural traditions, sustains millions of artisans, and preserves ancient weaving techniques. To protect this legacy, a critical need arises to distinguish genuine handloom products, exemplified by the renowned "gamucha" from India's northeast, from counterfeit powerloom imitations. Our study's objective is to create an AI tool for effortless detection of authentic handloom items amidst a sea of fakes. Six deep learning architectures-VGG16, VGG19, ResNet50, InceptionV3, InceptionResNetV2, and DenseNet201-were trained on annotated image repositories of handloom and powerloom towels (17,484 images in total, with 14,020 for training and 3464 for validation). A novel deep learning model was also proposed. Despite respectable training accuracies, the pre-trained models exhibited lower performance on the validation dataset compared to our novel model. The proposed model outperformed pre-trained models, demonstrating superior validation accuracy, lower validation loss, computational efficiency, and adaptability to the specific classification problem. Notably, the existing models showed challenges in generalizing to unseen data and raised concerns about practical deployment due to computational expenses. This study pioneers a computer-assisted approach for automated differentiation between authentic handwoven "gamucha"s and counterfeit powerloom imitations-a groundbreaking recognition method. The methodology presented not only holds scalability potential and opportunities for accuracy improvement but also suggests broader applications across diverse fabric products.
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Background: The Alternative Lengthening of Telomeres (ALT) pathway represents a non-canonical mechanism of telomere maintenance that operates independently of the conventional telomerase activity. The three biologically significant proteins, designated as SMARCAL1 (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A-like protein 1), DAXX (Death domain-associated protein 6) and ATRX (alpha-thalassemia/mental retardation, X-linked) are associated with ALT in certain cancer types. The purpose of this study was to identify the most high-risk nsSNPs (non-synonymous Single Nucleotide Polymorphisms) within these three genes and assess their impacts on the structure and function of the proteins they encode. Methods: The reported genetic polymorphisms of SMARCAL1, DAXX and ATRX genes were retrieved from the Ensembl database. Later, various computational tools like PROVEAN, PolyPhen2, SNPs and GO, SNAP2, Predict-SNP, Panther and PMut were used to predict the most deleterious nsSNPs. MutPred was used to understand the underlying molecular reasons of those nsSNPs being deleterious, followed by prediction of Post Translational Modification Sites (PTMs) using ModPred. I-Mutant and MUpro were used to predict the effect of SNP on energy stability. Later, 3D clustering analysis was done using Mutation 3D server. Moreover, ConSurf was utilized to identify the conservation scores of wild-type amino acids. Additionally, the NCBI conserved domain search tool was employed to pinpoint conserved domains within these three proteins. Project-Hope helped for biophysical validation, followed by prediction of these genes' interaction and function by using GeneMANIA. Result: Analysis on SMARCAL1 protein revealed that among 665 nsSNPs, four were identified as the most deleterious: L578S, T581S, P582A, and P582S. Similarly, within the DAXX protein, among a pool of 480 nsSNPs, P284S, R230C, and R230S were found out to be the most deleterious variants. In case of ATRX protein, V178D, R246C, and V277G, from the total of 1009 nsSNPs, were predicted to be the most deleterious. All these nsSNPs were found to occur at residue positions that are 100 % conserved within protein domains and were predicted to be most damaging from both structural and functional perspectives and highly destabilizing to their corresponding proteins. Conclusion: Computational investigation on the 3 proteins-SMARCAL1, DAXX and ATRX through different bioinformatics analysis tools concludes that the identified high risk nsSNPs of these proteins are pathogenic SNPs. These variants potentially exert functional and structural influences, thus making them valuable candidates for future genetic studies.
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Toxoplasma gondii is an intracellular protozoan parasite that causes toxoplasmosis in around one-third of the world population, particularly in pregnant women and immunocompromised individuals. Diabetes mellitus (DM) is one of the most severe global health challenges in the 21st century, and especially, type-2 diabetes mellitus (T2DM) accounts for 90% of the diabetes cases diagnosed globally. In Bangladesh, the rate of T2DM is rising gradually with the improvement in living standards. The aim of this study is to find out the correlation between latent toxoplasmosis and T2DM, emphasizing the pro-inflammatory cytokine immunity. For this, 100 (N = 100) patients with T2DM and 100 (N = 100) healthy controls were enrolled to determine the seroprevalence of toxoplasmosis using enzyme-linked immunosorbent assay (ELISA). In addition, ELISA was also performed to determine the level of pro-inflammatory cytokine, interleukin (IL)-12, to understand its role in the development of toxoplasmosis. In our study, 39.39% of the T2DM patients were positive with anti-T. gondii Immunoglobulin G by ELISA, whereas the rate of seropositivity in healthy controls was 39.73%. We did not find significant association between T. gondii infection and T2DM, but our data confirmed a high prevalence of chronic toxoplasmosis in Bangladeshi population. From hematology tests, it was found that the T2DM patients had significantly lower levels of total white blood cells (P = 0.0015), circulating eosinophils (P = 0.0026), and neutrophils (P = 0.0128) than the healthy controls. On the other hand, the levels of lymphocytes (P = 0.0204) and monocytes (P = 0.0067) were significantly higher in patients. Furthermore, T. gondii infected T2DM patients had significantly higher levels of IL-12 than the healthy controls (P = 0.026), suggesting a link between parasitic infection and IL-12 secretion. Further studies are to be performed to find out the exact cause of high prevalence of chronic T. gondii infection in Bangladeshi population.
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BACKGROUND AND AIM: Listeriosis in food animals bears a significant threat to human health. Detailed investigations into the cause facilitate proper management of the disease. This study reports the cultural, pathological, and molecular characterization of Listeria monocytogenes isolated from encephalitic goats from peri-urban Guwahati, Assam. MATERIALS AND METHODS: Out of nine suspected samples, five positive isolates of L. monocytogenes were subjected to bacteriological, biochemical, and molecular tests. The genus and species-specific L. monocytogenes 16S rRNA and prs genes were amplified by polymerase chain reaction (PCR) to yield 1200 and 370 bp sized products, respectively. The encephalitic form of the disease was characterized by circling movement, high fever, and terminal recumbence. RESULTS: All the five isolates were confirmed to be L. monocytogenes based on PCR amplification of genus and species-specific 16S rRNA and prs gene products. The isolates were sensitive to ciprofloxacin, oxytetracycline (OTC), and norfloxacin, but resistant to doxycycline and erythromycin. A high dose of OTC was used in a goat at the early stage of clinical symptom and the animal recovered clinically. CONCLUSION: Listeriosis in goats could pose a significant public health threat as the meat (occasionally milk) or meat products from goats are widely consumed by the people of Assam. Understanding the molecular epidemiological aspects of L. monocytogenes infections of food animal species should, therefore, be the priority in this part of the country.
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Porcine circovirus (PCV) infection has emerged as an alarming threat to the pig population of India, especially in the Northeastern region (NER) over the last 10 years. The present study is a comprehensive report of the seroepidemiology of PCV2 and its incidences in the pig population from organized and unorganized farms of the entire NER of India from 2011 to 2017. A total of 5697 serum samples were screened by ELISA and the mean positivity of PCV2 antibodies in suspected sera was 31.27%. A total of 22 confirmed cases of PCV2 infection were recorded during the years 2014-2017. Seroprevalence of PCV2 infection in sows causing reproductive disorders in NER suggested its higher incidence in organized farms (65.7%) as compared to unorganized farms (17.6%). A detailed pathological and histopathological examination of the tissue samples collected from the affected animals indicated the presence of PCV2. Molecular characterization and phylogenetic analysis of four PCV2 isolates depicted the circulation of PCV2d genotype in the states of Meghalaya and Assam.
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Infecciones por Circoviridae/veterinaria , Circovirus/aislamiento & purificación , Enfermedades Transmisibles Emergentes/veterinaria , Brotes de Enfermedades/veterinaria , Enfermedades de los Porcinos/epidemiología , Animales , Anticuerpos Antivirales/sangre , Infecciones por Circoviridae/epidemiología , Infecciones por Circoviridae/virología , Circovirus/genética , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/virología , Ensayo de Inmunoadsorción Enzimática/veterinaria , Granjas , Genotipo , India/epidemiología , Filogenia , Estudios Retrospectivos , Estudios Seroepidemiológicos , Porcinos , Enfermedades de los Porcinos/virologíaRESUMEN
The unicellular parasite Toxoplasma gondii infects warm-blooded animals and humans, and it is highly prevalent throughout the world. Infection of immunocompetent hosts is usually asymptomatic or benign but leads to long-term parasite persistence mainly within neural and muscular tissues. The transition from acute primary infection towards chronic toxoplasmosis is accompanied by a developmental switch from fast replicating and metabolically highly active tachyzoites to slow replicating and largely dormant bradyzoites within tissue cysts. Such developmental differentiation is critical for T. gondii in order to complete its life cycle and for pathogenesis. Herein, we summarize accumulating evidence indicating a major impact of the host cell physiology on stage conversion between the tachyzoite and the bradyzoite stage of the parasite. Withdrawal from cell cycle progression, proinflammatory responses, reduced availability of nutrients and extracellular adenosine can indeed induce tachyzoite-to-bradyzoite differentiation and tissue cyst formation. In contrast, high glycolytic activity as indicated by increased lactate secretion can inhibit bradyzoite formation. These examples argue for the intriguing possibility that after dissemination within its host, T. gondii can sense its cellular microenvironment to initiate the developmental program towards the bradyzoite stage in distinct cells. This may also explain the predominant localization of T. gondii in neural and muscular tissues during chronic toxoplasmosis.
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AIM: The present investigation was undertaken to elaborate hematobiochemical alterations of acute chlorpyriphos (CPF) toxicity in indigenous chicken. Since there is no available literature on the detailed hematobiochemical changes of CPF in indigenous chicken, hence, the present study was designed to establish toxicological effect of CPF on blood biochemical parameters of indigenous chicken which are at a great risk of exposure to pesticides. These will help physiologist, pathologist, and poultry scientists for effective production strategy as well as disease control regime. MATERIALS AND METHODS: The birds were divided into two major Groups I and II. Group I served as control and Group II was treated with CPF (36 mg/kg). Blood samples were assayed for hemoglobin (Hb), total erythrocyte count (TEC), total leukocyte count (TLC), differential leukocyte count, and biochemical constituents such as alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholinesterase (CHE), total protein, and uric acid. RESULTS: Hb, TEC, and TLC levels increased significantly (p<0.01) in toxin fed birds, whereas, lymphocyte percent decreased significantly, and heterophil percent increased significantly. Serum ALP, AST, ALT, and uric acid increased significantly in CPF treated birds. Decreased serum CHE values were observed in CPF fed group. The protein level remained almost same. Uric acid level was found to be increased significantly in the treated group compared to control. CONCLUSION: The results indicated that acute CPF intoxication produce changes in hematology and biochemical constituents of the treated birds.
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OBJECTIVE: The present study investigates the effect of oral administration of chlorpyrifos (CPF) in indigenous chicken. MATERIALS AND METHODS: The birds were divided into two groups I and II. Group I served as control and group II was treated with CPF (0.36 mg/kg) orally daily up to 12 weeks. Blood samples were assayed for hemoglobin (Hb), total erythrocyte count (TEC), total leukocyte count (TLC), differential leukocyte count, and biochemical constituents like alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), cholinesterase (CHE), total protein and uric acid. Representative pieces of tissues from liver and kidney were collected weekly for histopathological examination. RESULTS: A significant (P < 0.01) increase of Hb, TEC, TLC, and heterophil percent and decrease of lymphocyte percent was observed. Serum ALP, AST, ALT, and uric acid increased significantly and CHE values decreased significantly in CPF treated birds. The protein level remained similar. Uric acid level was found to be increased significantly in the treated group. The results indicate that chronic CPF intoxication produces hematological, biochemical, and pathological changes in treated birds.
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Pollos/metabolismo , Cloropirifos/toxicidad , Insecticidas/toxicidad , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Animales , Recuento de Células Sanguíneas , Análisis Químico de la Sangre , Pollos/sangre , Riñón/metabolismo , Riñón/patología , Hígado/metabolismo , Hígado/patología , Pruebas de Toxicidad SubagudaRESUMEN
Human immunodeficiency virus (HIV) possesses a major threat to the human life largely due to the unavailability of an efficacious vaccine and poor access to the antiretroviral drugs against this deadly virus. High mutation rate in the viral genome underlying the antigenic variability of the viral proteome is the major hindrance as far as the antibody based vaccine development is concerned. Although the exact mechanism by which CTL epitopes and the restricting HLA alleles mediate their action towards slow disease progression is still not clear, the important CTL restricted epitopes for controlling viral infections can be utilized in future vaccine design. This study was designed for the characterization the HIV-1 optimal CTL epitopes and their corresponding HLA alleles. CTL epitope cluster distribution analysis revealed only two HIV-1 proteins, namely, Nef and Gag, which have significant cluster forming capacity. We have found the role of specific HLA supertypes such as HLA B∗07, HLA B∗58, and HLA A∗03 in selecting the hydrophobic and conserved amino acid positions within Nef and Gag proteins, to be presented as epitopes. The analyses revealed that the clusters of optimal epitopes for Nef and p24 proteins of HIV-1 could potentially serve as a source of vaccine.
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Induction of HIV-1-specific cytotoxic T lymphocyte (CTL) responses largely depends upon the presentation of CTL epitopes to the CD8(+) T cells aided by a large number of different HLA class I alleles. Although several studies showed the clustering pattern of HIV-1 CTL epitopes, the underlying reason for this tendency remains unresolved. Moreover, the hypothesis that the CTL epitope clusters tend to coincide with the conserved and hydrophobic regions of HIV-1 proteins has been challenged in recent times. The present study aims to characterize and compare the HIV-1 CTL epitope clusters in terms of restricting HLA alleles, hydrophobicity, and sequence conservation in a proteome-wide manner by including a large number of experimentally validated CTL epitopes from the HIV Molecular Immunology Database. CTL epitope cluster distribution analysis in a proteome-wide manner revealed that only two HIV-1 proteins, namely Nef and Gag, have significant cluster-forming capacity where their epitope localization coincides with the hydrophobic and conserved regions. Furthermore, analyses of proteasomal cleavage sites and HLA anchoring motif frequencies in the epitope-dense regions highlighted the role of specific HLA supertypes such as HLA B*07, HLA B*58, HLA A*02, and HLA A*03 in selecting the hydrophobic and conserved amino acid positions within Nef and Gag proteins to be presented as epitopes. Based on our results, we hypothesize that the cluster-forming tendency of HIV-1 CTL epitopes is not a proteome-wide feature confined to Nef and Gag proteins. Their cluster-forming tendency largely depends on the host HLA alleles that contribute significantly in selecting functionally constrained hydrophobic regions within the HIV-1 proteome.
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Epítopos de Linfocito T/inmunología , Infecciones por VIH/inmunología , VIH-1/inmunología , Antígenos HLA/genética , Linfocitos T Citotóxicos/inmunología , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/inmunología , Presentación de Antígeno , Secuencia Conservada , Infecciones por VIH/virología , Antígenos HLA/inmunología , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/química , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/genética , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/química , Productos del Gen nef del Virus de la Inmunodeficiencia Humana/genéticaRESUMEN
Cancer is clearly the most deadly disease in the developed world as one in three people develop cancer during their lifetime. The cure for cancer is like the Holy Grail since most of the existing treatments are not effective enough to provide full protection from this disease. In recent years the burgeoning of sophisticated genomic, proteomic and bioinformatics techniques has made it possible for us to get a glimpse of the intricate interplay of numerous cellular genes and regulatory genetic elements that are responsible for the manifestation of cancerous phenotypes. With the use of modern genomic technologies we are now beginning to understand the enormous complexity of cancer. However there are few success stories as far as the treatment of cancer is concerned. For instance the treatments of leukemia and lymphoma have been established and proved to be satisfactory. Despite occasional successes the treatment for most cancers is still a long way from reality. In this editorial, we have addressed several reasons for the difficulties in cancer treatment.
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Hemolytic anemia and rhabdomyolysis have been often reported to be an adverse effect of drug- and chemical-induced toxicity both in experimental and real-life scenario. para-Phenylenediamine (PPD) is a derivative of para-nitroaniline and has been found as an ingredient of almost all hair dye formulations in varying concentrations from 2% to 4% w/v. Earlier studies have reported that the accidental oral ingestion of PPD in humans can lead to acute renal failure because of rhabdomyolysis. In the present investigation, we have tested the chronic topical application of PPD and its effect on the renal histology of Sprague-Dawley rats. The experiment provides clear evidence that topically applied PPD induces hemolytic anemia as evident from the decrease in the total RBC count, packed cell volume, and hemoglobin content apart from rhabdomyolysis which subsequently causes acute renal failure in rats.
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Beta thalassemia major is an inherited disease resulting from reduction or total lack of beta globin chains. Patients with this disease need repeated blood transfusion for survival. This may cause oxidative stress and tissue injury due to iron overload, altered antioxidant enzymes, and other essential trace element levels. The aim of this review is to scrutinize the relationship between oxidative stress and serum trace elements, degree of damage caused by oxidative stress, and the role of antioxidant enzymes in beta thalassemia major patients. The findings indicate that oxidative stress in patients with beta thalassemia major is mainly caused by tissue injury due to over production of free radical by secondary iron overload, alteration in serum trace elements and antioxidant enzymes level. The role of trace elements like selenium, copper, iron, and zinc in beta thalassemia major patients reveals a significant change of these trace elements. Studies published on the status of antioxidant enzymes like catalase, superoxide dismutase, glutathione, and glutathione S-transferase in beta thalassemia patients also showed variable results. The administration of selective antioxidants along with essential trace elements and minerals to reduce the extent of oxidative damage and related complications in beta thalassemia major still need further evaluation.
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Thalassemia and other structural haemoglobinopathies are the major erythrocyte formation disorder prevalent in certain parts of the world including Bangladesh. We investigated 600 cases of anaemic patients referred from various parts of the country for diagnosis and counselling during 3 months (April to June 2011) of time. The most common form of haemoglobin (Hb) formation disorder observed in 600 subjects studied was ß-thalassemia minor (21.3%). Two other conditions, such as E-ß-Thalassemia and HbE trait, were also fairly common (13.5 and 12.1%, resp.) in the total subjects studied. Other forms of haemoglobin formation disorders observed were HbE disease (9.2%), Hb D/S trait (0.7%), ß-thalassemia major (0.5%), and δ-ß-thalassemia (0.5%). The majority of the haemoglobinopathies belonged to neonatal to childhood period (0-15 years), followed by reproductive age group (16-45 years). Few old-age (46+ years) cases were also detected in course of clinical complications.
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Vibrio cholerae O1 is a noninvasive enteric pathogen and serves as a model for studies of mucosal immunity. Although symptomatic V. cholerae infection induces durable protection against subsequent disease, vaccination with oral killed whole-cell V. cholerae stimulates less long-lasting protection against cholera. In this study, we demonstrated that cholera induces an early proinflammatory cellular immune response that results in priming of Th1- and Th17-type cytokine responses to ex vivo antigenic stimulation and an increase in the ratio of Th1 to Th2 CD4(+) T-cell responses. Comparable priming of Th1 and Th17 responses, with an increased ratio of Th1 to Th2 CD4(+) T-cell responses, was not observed in subjects who received two doses of the oral cholera vaccine Dukoral (a whole-cell cholera toxin B subunit containing [WC-CTB] vaccine). These findings suggest that natural V. cholerae infection induces an early, proinflammatory cellular immune response, despite the apparent lack of clinical signs of inflammation. The failure of the WC-CTB vaccine to activate equivalent, CD4(+) T-cell responses is a potential explanation for the shorter duration of protection following immunization with this vaccine. Additional studies are needed to determine whether these early T-cell-mediated events predict the subsequent duration of immunologic memory.
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Sangre/inmunología , Linfocitos T CD4-Positivos/inmunología , Cólera/inmunología , Mucosa Intestinal/inmunología , Vibrio cholerae O1/inmunología , Administración Oral , Adolescente , Adulto , Cólera/microbiología , Vacunas contra el Cólera/administración & dosificación , Vacunas contra el Cólera/inmunología , Citocinas/metabolismo , Humanos , Persona de Mediana Edad , Células TH1/inmunología , Células Th17/inmunología , Células Th2/inmunología , Adulto JovenRESUMEN
BACKGROUND: Salmonella enterica serotype Typhi is a human-restricted intracellular pathogen and the cause of typhoid fever. Cellular immune responses are required to control and clear Salmonella infection. Despite this, there are limited data on cellular immune responses in humans infected with wild type S. Typhi. METHODOLOGY/PRINCIPAL FINDINGS: For this work, we used an automated approach to purify a subset of S. Typhi proteins identified in previous antibody-based immuno-affinity screens and antigens known to be expressed in vivo, including StaF-putative fimbrial protein-STY0202, StbB-fimbrial chaperone-STY0372, CsgF-involved in curli production-STY1177, CsgD- putative regulatory protein-STY1179, OppA-periplasmic oligopeptide binding protein precursor-STY1304, PagC-outer membrane invasion protein-STY1878, and conserved hypothetical protein-STY2195; we also generated and analyzed a crude membrane preparation of S. Typhi (MP). In comparison to samples collected from uninfected Bangladeshi and North American participants, we detected significant interferon-γ responses in PBMCs stimulated with MP, StaF, StbB, CsgF, CsgD, OppA, STY2195, and PagC in patients bacteremic with S. Typhi in Bangladesh. The majority of interferon-γ expressing T cells were CD4 cells, although CD8 responses also occurred. We also assessed cellular proliferation responses in bacteremic patients, and confirmed increased responses in infected individuals to MP, StaF, STY2195, and PagC in convalescent compared to acute phase samples and compared to controls. StaF is a fimbrial protein homologous to E. coli YadK, and contains a Pfam motif thought to be involved in cellular adhesion. PagC is expressed in vivo under the control of the virulence-associated PhoP-regulon required for intra-macrophage survival of Salmonella. STY2195 is a conserved hypothetical protein of unknown function. CONCLUSION/SIGNIFICANCE: This is the first analysis of cellular immune responses to purified S. Typhi antigens in patients with typhoid fever. These results indicate that patients generate significant CD4 and CD8 interferon-γ responses to specific S. Typhi antigens during typhoid fever, and that these responses are elevated at the time of clinical presentation. These observations suggest that an interferon-γ based detection system could be used to diagnose individuals with typhoid fever during the acute stage of illness.