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1.
Physiol Res ; 72(3): 337-347, 2023 07 14.
Article in English | MEDLINE | ID: mdl-37449747

ABSTRACT

Waterpipe tobacco smoking (WPS) inhalation has been shown to trigger endothelial dysfunction and atherosclerosis. However, the mechanisms underlying these effects are still unknown. Here, we assessed the impact and underlying mechanism of WPS exposure for one month on endothelial dysfunction using aortic tissue of mice. The duration of the session was 30 min/day and 5 days/week. Control mice were exposed to air. Inhalation of WPS induced an increase in the number of macrophages and neutrophils and the concentrations of protein, tumor necrosis factor alpha (TNF alpha), interleukin (IL)-1beta, and glutathione in bronchoalveolar lavage fluid. Moreover, the concentrations of proinflammatory cytokines (TNF alpha, IL-6 and IL-1beta), adhesion molecules (intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin and P-selectin) and markers of oxidative stress (lipid peroxidation, glutathione, superoxide dismutase and nitric oxide) in aortic homogenates of mice exposed to WPS were significantly augmented compared with air exposed mice. Likewise, the concentration of galectin-3 was significantly increased in the aortic homogenates of mice exposed to WPS compared with control group. WPS inhalation induced vascular DNA damage assessed by comet assay and apoptosis characterized by a significant increase in cleaved caspase-3. While the aortic expression of phosphorylated nuclear factor kappaB (NF-kappaB) was significantly increased following WPS inhalation, the concentration of sirtuin 1 (SIRT1) was significantly decreased in WPS group compared with air-exposed group. In conclusion, our study provided evidence that WPS inhalation triggers lung injury and endothelial inflammation, oxidative stress and apoptosis which were associated with nuclear factor-kappaB activation and SIRT1 down-regulation.


Subject(s)
Lung Injury , Vascular Diseases , Water Pipe Smoking , Animals , Mice , Tumor Necrosis Factor-alpha , Water Pipe Smoking/adverse effects , Sirtuin 1 , Glutathione/metabolism , NF-kappa B/metabolism
2.
Inform Med Unlocked ; 27: 100798, 2021.
Article in English | MEDLINE | ID: mdl-34812411

ABSTRACT

Genomic data analysis is a fundamental system for monitoring pathogen evolution and the outbreak of infectious diseases. Based on bioinformatics and deep learning, this study was designed to identify the genomic variability of SARS-CoV-2 worldwide and predict the impending mutation rate. Analysis of 259044 SARS-CoV-2 isolates identified 3334545 mutations with an average of 14.01 mutations per isolate. Globally, single nucleotide polymorphism (SNP) is the most prevalent mutational event. The prevalence of C > T (52.67%) was noticed as a major alteration across the world followed by the G > T (14.59%) and A > G (11.13%). Strains from India showed the highest number of mutations (48) followed by Scotland, USA, Netherlands, Norway, and France having up to 36 mutations. D416G, F106F, P314L, UTR:C241T, L93L, A222V, A199A, V30L, and A220V mutations were found as the most frequent mutations. D1118H, S194L, R262H, M809L, P314L, A8D, S220G, A890D, G1433C, T1456I, R233C, F263S, L111K, A54T, A74V, L183A, A316T, V212F, L46C, V48G, Q57H, W131R, G172V, Q185H, and Y206S missense mutations were found to largely decrease the structural stability of the corresponding proteins. Conversely, D3L, L5F, and S97I were found to largely increase the structural stability of the corresponding proteins. Multi-nucleotide mutations GGG > AAC, CC > TT, TG > CA, and AT > TA have come up in our analysis which are in the top 20 mutational cohort. Future mutation rate analysis predicts a 17%, 7%, and 3% increment of C > T, A > G, and A > T, respectively in the future. Conversely, 7%, 7%, and 6% decrement is estimated for T > C, G > A, and G > T mutations, respectively. T > G\A, C > G\A, and A > T\C are not anticipated in the future. Since SARS-CoV-2 is mutating continuously, our findings will facilitate the tracking of mutations and help to map the progression of the COVID-19 intensity worldwide.

3.
Genet Mol Res ; 13(4): 10194-203, 2014 Dec 04.
Article in English | MEDLINE | ID: mdl-25501231

ABSTRACT

Recent genome wide association studies identified many loci in several genes that have been consistently associated with type 2 diabetes mellitus in various ethnic populations. Among the genes that were most strongly associated with diabetes were fat mass- and obesity-associated, melanocortin 4 receptor, solute carrier family 30 member 8 (SLC30A8), and a member of the potassium voltage-gated channels. In the present study, we examined the association between variants in fat mass- and obesity-associated [rs9939609 (A/T)], melanocortin 4 receptor [rs17782313 (C/T), and rs12970134 (A/G)], SLC30A8 [rs13266634 (C/T)], and a member of the potassium voltage-gated channels [rs2237892(C/T)] genes in diabetes patients from Saudi Arabia. Genotypes were determined using the TaqMan single-nucleotide polymorphism genotype analysis technique. Minor allele frequency of the 4 variants tested was comparable between type 2 diabetes cases and controls. We observed an association between allele variants of SLC30A8 [rs13266634 (C/T)] and type 2-diabetes (P = 0.04). The other single-nucleotide polymorphisms examined in this study showed moderate or no correlation with diabetes in Saudis. Our data indicate that the SLC30A8 polymorphisms are associated with type 2 diabetes in the Saudi population. There is no evidence supporting an association between variants in the fat mass- and obesity-associated and melanocortin 4 receptor, and a member of the potassium voltage-gated channels genes and type 2 diabetes in the Saudi population.


Subject(s)
Cation Transport Proteins/genetics , Diabetes Mellitus, Type 2/genetics , KCNQ1 Potassium Channel/genetics , Polymorphism, Single Nucleotide , Proteins/genetics , Receptor, Melanocortin, Type 4/genetics , Adult , Alpha-Ketoglutarate-Dependent Dioxygenase FTO , Case-Control Studies , Female , Genetic Association Studies , Genetic Predisposition to Disease , Genotype , Humans , Male , Middle Aged , Saudi Arabia , Zinc Transporter 8
4.
Bull Entomol Res ; 104(6): 707-15, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25033090

ABSTRACT

The common green lacewing Chrysoperla carnea is a key biological control agent employed in integrated pest management (IPM) programs for managing various insect pests. Spinosad is used for the management of pests in ornamental plants, fruit trees, vegetable and field crops all over the world, including Pakistan. A field-collected population of C. carnea was selected with spinosad and fitness costs and realized heritability were investigated. After selection for five generations, C. carnea developed 12.65- and 73.37-fold resistance to spinosad compared to the field and UNSEL populations. The resistant population had a relative fitness of 1.47, with substantially higher emergence rate of healthy adults, fecundity and hatchability and shorter larval duration, pupal duration, and development time as compared to a susceptible laboratory population. Mean relative growth rate of larvae, intrinsic rate of natural population increase and biotic potential was higher for the spinosad-selected population compared to the susceptible laboratory population. Chrysoperla species are known to show resistance to insecticides which makes the predator compatible with most IPM systems. The realized heritability (h 2) value of spinosad resistance was 0.37 in spinosad-selected population of C. carnea.


Subject(s)
Insecta/physiology , Insecticide Resistance , Insecticides/toxicity , Macrolides/toxicity , Animals , Biological Control Agents , Drug Combinations , Genetic Fitness , Inheritance Patterns , Insecta/drug effects , Insecta/genetics , Insecta/growth & development , Insecticide Resistance/genetics , Larva/drug effects , Larva/genetics , Larva/physiology
6.
Genet Mol Res ; 13(2): 2886-905, 2014 Mar 17.
Article in English | MEDLINE | ID: mdl-24682982

ABSTRACT

The domesticated one-humped Arabian camel, Camelus dromedarius, is one of the most important animals in the Arabian Peninsula. Most of its life, this animal is exposed to both intrinsic and extrinsic genotoxic factors that are known to cause gross metabolic alterations in many organisms. This study determined the full length coding sequence of 3 cytochrome P450s cDNAs; namely, CYP450 1A1, CYP450 2C and CYP450 3A using reverse transcription polymerase chain reaction. The C. dromedarius CYP450s 1A1, 2C, and 3A have open reading frames of 1563, 1473, and 1566 bp and cDNAs that encode proteins of 520, 490, and 521 amino acid residues, respectively. The molecular weights calculated for CYP1A1, 2C, and 3A were found to be 58.651, 56.03, and 58.594 kDa, while the predicted calculated isoelectric points using a computer algorithm were 7.315, 6.579, and 9.46. The deduced amino acid sequences of these CYPs showed the membrane anchored signal peptide, the conserved proline-rich amino terminus and the characteristic heme-binding signature localized near the carboxy terminus of the protein.


Subject(s)
Camelus/genetics , Cytochrome P-450 CYP1A1/genetics , Cytochrome P-450 CYP3A/genetics , Cytochrome P-450 Enzyme System/genetics , Animals , Cloning, Molecular , DNA, Complementary/genetics , Sequence Alignment , Sequence Homology, Amino Acid
8.
J Assoc Physicians India ; 62(7): 620-3, 2014 Jul.
Article in English | MEDLINE | ID: mdl-25672040

ABSTRACT

BACKGROUND: Myocardial Infarction and Ischaemic stroke are potential outcome after an electric shock though it is seen relatively rarely. CASE REPORT: Here, we report a man with myocardial infarction as well as Ischaemic stroke occurring together who suffered a domestic low- voltage (220-240V) electrical injury. Myocardial infarction was evident by cardiac enzymes, electrocardiography and echocardiography while Ischemic stroke was evident on CT scan head: Patient was treated on line of acute ischaemic stroke and myocardial infarction. Patient was discharged in satisfactory condition. CONCLUSION: Electric Injury due to low voltage AC may cause ischaemic stroke as well as myocardial Infarction altogether. Vasospasm caused by electrical injury, direct thermal injury may be the cause of concurrent phenomenon.


Subject(s)
Anterior Wall Myocardial Infarction/diagnosis , Electric Injuries/diagnosis , Infarction, Middle Cerebral Artery/diagnosis , Adult , Burns, Electric/diagnosis , Comorbidity , Echocardiography , Electrocardiography , Facial Injuries/diagnosis , Humans , India , Male , Skin/injuries , Tomography, X-Ray Computed , Troponin T/blood
9.
Genet Mol Res ; 12(4): 5634-9, 2013 Nov 18.
Article in English | MEDLINE | ID: mdl-24301932

ABSTRACT

We tested the cross-amplification of eight microsatellites developed for Bengalese finch in African Silverbill (Lonchura cantans). In order to develop resources for conservation genetic studies in the species L. cantans, we tested the amplification success and polymorphism in eight previously developed microsatellite loci, in L. cantans. All eight microsatellite markers were successfully amplified, of which all were polymorphic, with 3 to 9 alleles and an expected heterozygosity (HE) ranging from 0.606 to 0.718. On average, there were 5.25 alleles/locus and a mean HE of 0.6456. These eight polymorphic markers could be of potential use in studies of genetic variability, population structure, and reproductive strategy of African Silverbills. The markers tested should be useful for population and conservation genetic studies in this genus, and, in particular, for species closely related to the source species, L. cantans.


Subject(s)
Microsatellite Repeats , Polymorphism, Genetic , Sparrows/genetics , Alleles , Animals , Heterozygote
10.
Bull Environ Contam Toxicol ; 88(6): 894-6, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22437566

ABSTRACT

A field experiment was conducted at Agricultural Research Station, Durgapura, Jaipur during kharif 2008 to study the dissipation of Quinalphos (25 EC) in/on brinjal and soil, when sprayed at its recommended dose (375 g a.i. ha(-1)) and double of the recommended dose (750 g a.i. ha(-1)). The residue data revealed the magnitude of dissipation and persistence by calculating safety parameters like RL(50) and T(tol). The initial deposit of Quinalphos in brinjal at 375 and 750 g a.i. ha(-1) were recorded as 0.0866 and 0.1517 mg kg(-1), respectively which reached to below detectable level (0.01 mg kg(-1)) in 7 and 10 days at recommended (375 g a.i. ha(-1)) and double of the recommended dose (750 g a.i. ha(-1)), respectively. The residues, however, had a half life value (RL(50)) of 2 days for lower dose and 3 days for higher dose. Hence 6 and 9 days waiting period was suggested for recommended and double of the recommended dose, respectively. No residues were detected in soil in treated plots at both the treatment levels 30 days after the spray of insecticide to the crop.


Subject(s)
Insecticides/chemistry , Organothiophosphorus Compounds/chemistry , Soil Pollutants/chemistry , Soil/chemistry , Solanum melongena/chemistry , Food Contamination/analysis , Insecticides/analysis , Models, Chemical , Organothiophosphorus Compounds/analysis , Risk Assessment , Soil Pollutants/analysis
11.
Br J Cancer ; 102(4): 748-53, 2010 Feb 16.
Article in English | MEDLINE | ID: mdl-20087354

ABSTRACT

BACKGROUND: alpha-Fetoprotein (AFP) is a tumour-associated antigen in hepatocellular carcinoma (HCC) and is a target for immunotherapy. However, there is little information on the pattern of CD4 (Th1) and CD8 (Tc1) T-cell response to AFP in patients with HCC and their association with the clinical characteristics of patients. METHODS: We therefore analysed CD4 and CD8 T-cell responses to a panel of AFP-derived peptides in a total of 31 HCC patients and 14 controls, using an intracellular cytokine assay for IFN-gamma. RESULTS: Anti-AFP Tc1 responses were detected in 28.5% of controls, as well as in 25% of HCC patients with Okuda I (early tumour stage) and in 31.6% of HCC patients with stage II or III (late tumour stages). An anti-AFP Th1 response was detected only in HCC patients (58.3% with Okuda stage I tumours and 15.8% with Okuda stage II or III tumours). Anti-AFP Th1 response was mainly detected in HCC patients who had normal or mildly elevated serum AFP concentrations (P=0.00188), whereas there was no significant difference between serum AFP concentrations in these patients and the presence of an anti-AFP Tc1 response. A Th1 response was detected in 44% of HCC patients with a Child-Pugh A score (early stage of cirrhosis), whereas this was detected in only 15% with a B or C score (late-stage cirrhosis). In contrast, a Tc1 response was detected in 17% of HCC patients with a Child-Pugh A score and in 46% with a B or C score. CONCLUSION: These results suggest that anti-AFP Th1 responses are more likely to be present in patients who are in an early stage of disease (for both tumour stage and liver cirrhosis), whereas anti-AFP Tc1 responses are more likely to be present in patients with late-stage liver cirrhosis. Therefore, these data provide valuable information for the design of vaccination strategies against HCC.


Subject(s)
Carcinoma, Hepatocellular/immunology , Liver Neoplasms/immunology , T-Lymphocytes, Cytotoxic/immunology , Th1 Cells/immunology , alpha-Fetoproteins/immunology , Adult , Aged , Aged, 80 and over , Carcinoma, Hepatocellular/blood , Carcinoma, Hepatocellular/complications , Carcinoma, Hepatocellular/pathology , Case-Control Studies , Female , Follow-Up Studies , Hepatitis C/complications , Hepatitis C/immunology , Humans , Liver Cirrhosis/complications , Liver Cirrhosis/immunology , Liver Neoplasms/blood , Liver Neoplasms/complications , Liver Neoplasms/pathology , Lymphocyte Activation/physiology , Male , Middle Aged , Neoplasm Staging , T-Lymphocytes, Cytotoxic/pathology , Th1 Cells/pathology , Up-Regulation/immunology
12.
Micron ; 39(8): 1049-61, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18586502

ABSTRACT

Plant tissues must be dehydrated for observation in most electron microscopes. Although a number of sample processing techniques have been developed for preserving plant tissues in their original form and structure, none of them are guaranteed artefact-free. The current paper reviews common scanning electron microscopy techniques and the sample preparation methods employed for visualisation of leaves under specific types of electron microscopes. Common artefacts introduced by specific techniques on different leaf types are discussed. Comparative examples are depicted from our lab using similar techniques; the pros and cons for specific techniques are discussed. New promising techniques and microscopes, which can alleviate some of the problems encountered in conventional methods of leaf sample processing and visualisation, are also discussed. It is concluded that the choice of technique for a specific leaf sample is dictated by the surface features that need to be preserved (such as trichomes, epidermal cells or wax microstructure), the resolution to be achieved, availability of the appropriate processing equipment and the technical capabilities of the available electron microscope.


Subject(s)
Microscopy, Electron, Scanning/methods , Plants/ultrastructure , Freeze Drying , Tissue Fixation
13.
Int J Tuberc Lung Dis ; 12(3): 326-31, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18284840

ABSTRACT

SETTING: Pakistan ranks sixth in the world in terms of tuberculosis (TB) burden, with a World Health Organization estimated incidence of 181 per 100000, or 286000 new cases annually. Hospital-based data indicate a significant problem of multidrug-resistant TB (MDR-TB) in the country and highlight the need to assess its extent at community level. In this cross-sectional study, sputum samples from 742 untreated newly diagnosed pulmonary TB patients from all over the country were used. OBJECTIVE: To assess the prevalence of primary drug resistance in Pakistan. RESULTS: Of 672 culture-positive patients, 76 (11.3%) showed resistance to one or more drugs. Resistance to streptomycin (10 microg/ml) was found in 36 (5.4%) patients, isoniazid (INH) (1 microg/ml) in 51 (7.6%), rifampicin (RMP) (5 microg/ml) in 15 (2.2%), ethambutol (10 microg/ml) in 12 (1.8%) and pyrazinamide in 22 (3.3%) samples. Forty-six (6.8%) of the isolates tested were resistant to a single drug, 10 (1.5%) to two drugs, 12 (1.8%) to three drugs, and 6 (0.9%) to four drugs, while 2 (0.3%) isolates were resistant to all five first-line agents. Primary MDR-TB was 1.8% (n=12) (INH 1 microg/ml, RMP 5 microg/ml). CONCLUSION: The results of this study show a prevalence of primary MDR-TB in Pakistan of <2%, which needs to be addressed through an effective DOTS strategy.


Subject(s)
Tuberculosis, Multidrug-Resistant/epidemiology , Tuberculosis, Pulmonary/epidemiology , Adolescent , Adult , Antitubercular Agents/pharmacology , Cross-Sectional Studies , Drug Resistance, Multiple, Bacterial , Female , Humans , Male , Mycobacterium tuberculosis/drug effects , Pakistan/epidemiology , Prevalence , Sputum/microbiology , Tuberculosis, Pulmonary/drug therapy
14.
J Immunol ; 167(9): 5217-25, 2001 Nov 01.
Article in English | MEDLINE | ID: mdl-11673535

ABSTRACT

The wide spectrum of clinical outcomes following infection with Mycobacterium tuberculosis is largely determined by the host immune response; therefore, we studied several clinically defined groups of individuals (n = 120) that differ in their ability to contain the bacillus. To quantitate M. tuberculosis-specific T cells directly ex vivo, we enumerated IFN-gamma-secreting CD4 T cells specific for ESAT-6, a secreted Ag that is highly specific for M. tuberculosis, and a target of protective immune responses in animal models. We found that frequencies of circulating ESAT-6 peptide-specific IFN-gamma-secreting CD4 T cells were higher in latently infected healthy contacts and subjects with minimal disease and low bacterial burdens than in patients with culture-positive active pulmonary tuberculosis (p = 0.009 and p = 0.002, respectively). Importantly, the frequency of these Ag-specific CD4 T cells fell progressively in all groups with treatment (p = 0.005), suggesting that the lower responses in patients with more extensive disease were not due to tuberculosis-induced immune suppression. This population of M. tuberculosis Ag-specific Th1-type CD4 T cells appears to correlate with clinical phenotype and declines during successful therapy; these features are consistent with a role for these T cells in the containment of M. tuberculosis in vivo. Such findings may assist in the design and evaluation of novel tuberculosis vaccine candidates.


Subject(s)
Antigens, Bacterial/immunology , CD4-Positive T-Lymphocytes/immunology , Interferon-gamma/biosynthesis , Tuberculosis/immunology , Adult , Aged , Bacterial Proteins , Cell Polarity , Epitopes, T-Lymphocyte , Female , HLA-DQ Antigens/physiology , Humans , Male , Middle Aged , Tuberculosis/drug therapy
15.
Lancet ; 357(9273): 2017-21, 2001 Jun 23.
Article in English | MEDLINE | ID: mdl-11438135

ABSTRACT

BACKGROUND: Identification of individuals latently infected with Mycobacterium tuberculosis is an important part of tuberculosis control. The current method, the tuberculin skin test (TST), has poor specificity because of the antigenic cross-reactivity of purified protein derivative (PPD) with M bovis BCG vaccine and environmental mycobacteria. ESAT-6 is a secreted antigen that is highly specific for M tuberculosis complex, but is absent from M bovis BCG. With an enzyme-linked immunospot (ELISPOT) assay for interferon gamma, we have identified ESAT-6-specific T cells as an accurate marker of M tuberculosis infection. METHODS: We did a prospective, masked study of 50 healthy contacts, with varying but well defined degrees of exposure to M tuberculosis, who attended an urban contact-tracing clinic. We assessed and compared the efficacy of our assay and TST for detection of symptomless infected individuals by correlation of test results with the degree of exposure to an infectious index case. FINDINGS: The ESAT-6 ELISPOT assay results had a strong positive relation with increasing intensity of exposure (odds ratio=9.0 per unit increase in level of exposure [95% CI 2.6--31.6], p=0.001), whereas TST results had a weaker relation with exposure (1.9 [1.0--3.5], p=0.05). By contrast, ELISPOT results were not correlated with BCG vaccination status (p=0.7), whereas TST results were significantly more likely to be positive in BCG-vaccinated contacts (12.1 [1.3--115.7], p=0.03). INTERPRETATION: This new antigen-specific T cell-based assay could allow more accurate identification of symptom-free individuals recently exposed to M tuberculosis, and thereby help to improve tuberculosis control.


Subject(s)
Antigens, Bacterial/metabolism , Contact Tracing/methods , Immunoenzyme Techniques/methods , Mycobacterium tuberculosis/immunology , Tuberculosis/epidemiology , Adult , Bacterial Proteins , Female , Humans , Interferon-gamma , Logistic Models , Male , Prospective Studies , T-Lymphocytes/immunology , Tuberculin Test , Tuberculosis/blood , Tuberculosis/diagnosis
16.
Am J Respir Crit Care Med ; 163(4): 824-8, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11282752

ABSTRACT

There is no reliable means of detecting latent M. tuberculosis infection, and even in patients with active tuberculosis, infection is often unconfirmed. We hypothesized that M. tuberculosis antigen-specific T cells might reliably indicate infection. We enumerated peripheral blood-derived interferon gamma (IFN-gamma)-secreting T cells responding to epitopes from ESAT-6, an antigen that is highly specific for M. tuberculosis complex but absent from BCG, in four groups of individuals. Forty-five of 47 patients with bacteriologically confirmed tuberculosis had ESAT-6-specific IFN-gamma-secreting T cells, compared with four of 47 patients with nontuberculous illnesses, indicating that these T cells are an accurate marker of M. tuberculosis infection. This assay thus has a sensitivity of 96% (95% confidence interval [CI] 92-100) for detecting M. tuberculosis infection in this patient population. By comparison, of the 26 patients with tuberculosis who had a diagnostic tuberculin skin test (TST), only 18 (69%) were positive (p = 0.003). In addition, 22 of 26 (85%) TST-positive exposed household contacts had ESAT-6-specific T cells, whereas zero of 26 unexposed BCG-vaccinated subjects responded. This approach enables rapid detection of M. tuberculosis infection in patients with active tuberculosis and in exposed asymptomatic individuals at high risk of latent infection; it also successfully distinguishes between M. tuberculosis infection and BCG vaccination. This capability may facilitate tuberculosis control in nonendemic regions.


Subject(s)
Antigens, Bacterial/analysis , CD4 Antigens/analysis , Epitopes, T-Lymphocyte/analysis , Mycobacterium tuberculosis/isolation & purification , Tuberculosis/diagnosis , Adolescent , Adult , Aged , CD4 Lymphocyte Count , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Prospective Studies , Reference Values , Sensitivity and Specificity , Tuberculin Test , Tuberculosis/immunology
17.
J Infect Dis ; 183(3): 469-77, 2001 Feb 01.
Article in English | MEDLINE | ID: mdl-11133379

ABSTRACT

Knowledge of the prevalence of latent Mycobacterium tuberculosis infection is crucial for effective tuberculosis control, but tuberculin skin test surveys have major limitations, including poor specificity because of the broad antigenic cross-reactivity of tuberculin. The M. tuberculosis RD1 genomic segment encodes proteins, such as early secretory antigenic target (ESAT)-6, that are absent from M. bovis bacille Calmette-Guérin (BCG) and most environmental mycobacteria. We recently identified circulating ESAT-6-specific T cells as an accurate marker of M. tuberculosis infection. Here, interferon-gamma-secreting T cells specific for peptides derived from ESAT-6 and a second RD1 gene product, CFP10, were enumerated in 100 prospectively recruited healthy adults in Bombay (Mumbai), India. Eighty percent responded to >/=1 antigen, and many donors had high frequencies of T cells that were specific for certain immunodominant peptides. In contrast, of 40 mostly BCG-vaccinated, United Kingdom-resident healthy adults, none responded to either antigen. This study suggests an 80% prevalence of latent M. tuberculosis infection in urban India.


Subject(s)
Antigens, Bacterial/immunology , Bacterial Proteins/immunology , Mycobacterium tuberculosis/immunology , T-Lymphocytes/immunology , Tuberculosis/epidemiology , Adolescent , Adult , Aged , Epitope Mapping , Female , HIV Infections/complications , Humans , India/epidemiology , Interferon-gamma/biosynthesis , Male , Middle Aged , Prevalence , Tuberculosis/diagnosis , Tuberculosis/immunology , Tuberculosis/microbiology , Urban Health
18.
Eur J Immunol ; 30(9): 2713-21, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11009107

ABSTRACT

MHC class I-restricted CD8 cytotoxic T lymphocytes (CTL) are essential for protective immunity to Mycobacterium tuberculosis in animal models but their role in humans remains unclear. We therefore studied subjects who had successfully contained M. tuberculosis infection in vivo, i.e. exposed healthy household contacts and individuals with inactive self-healed pulmonary tuberculosis. Using the ELISPOT assay for IFN-gamma, we screened peptides from ESAT-6, a secreted antigen that is highly specific for M. tuberculosis. We identified a novel nonamer epitope: unstimulated peripheral blood-derived CD8 T cells displayed peptide-specific IFN-gamma release ex vivo while CD8 T cell lines and clones exhibited HLA-A68.02-restricted cytolytic activity and recognized endogenously processed antigen. The frequency of CD8 CTL specific for this single M. tuberculosis epitope, 1/2500 peripheral blood lymphocytes, was equivalent to the combined frequency of all IFN-gamma-secreting purified protein derivative-reactive T cells ex vivo. This highly focused CTL response was maintained in an asymptomatic contact over 2 years and is the most potent antigen-specific antimycobacterial CD8 CTL response hitherto described. Thus, human M. tuberculosis-specific CD8 CTL are not necessarily associated with active disease per se. Rather, our results are consistent with a protective role for these ESAT-6-specific CD8 T cells in the long-term control of M. tuberculosis in vivo in humans.


Subject(s)
HLA-A Antigens/physiology , Interferon-gamma/metabolism , Mycobacterium tuberculosis/immunology , T-Lymphocytes, Cytotoxic/immunology , Tuberculosis/immunology , Amino Acid Sequence , Antigen Presentation , Antigens, Bacterial/immunology , Bacterial Proteins , Humans , Molecular Sequence Data , Peptide Fragments/immunology
20.
J Infect Dis ; 180(5): 1656-64, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10515829

ABSTRACT

The RTS,S/SBAS2 vaccine confers sterile protection against Plasmodium falciparum sporozoite challenge. The mechanisms underlying this are of great interest, yet little is known about the immune effector mechanisms induced by this vaccine. The immune responses induced by RTS,S/SBAS2 were characterized in 10 malaria-naive volunteers. Several epitopes in the circumsporozoite protein (CSP) were identified as targets of cultured interferon (IFN)-gamma-secreting CD4+ T cells. RTS,S-specific IFN-gamma-secreting effector T cells were induced in 8 subjects; this ex vivo response mapped to a single peptide in Th2R. CSP-specific CD8+ cytotoxic T lymphocytes were not detected. RTS, S-specific IFN-gamma production was universal, whereas interleukin-4 and -5 production was rare. RTS,S-specific lymphoproliferative responses and antibodies to CSP were strongly induced in all volunteers. Responses waned with time but were boostable. Thus, RTS, S/SBAS2 is a potent inducer of Th1-type cellular and humoral immunity. These results highlight possible immune mechanisms of protection and have important implications for vaccine design in general.


Subject(s)
Antibodies, Protozoan/blood , Malaria Vaccines/immunology , Plasmodium falciparum/immunology , Protozoan Proteins/immunology , Th1 Cells/immunology , Vaccines, Synthetic/immunology , Adult , Amino Acid Sequence , Animals , CD4-Positive T-Lymphocytes/immunology , Epitopes/chemistry , Hepatitis B Surface Antigens/immunology , Humans , Interferon-gamma/biosynthesis , Lymphocyte Activation , Malaria Vaccines/administration & dosage , Malaria, Falciparum/prevention & control , Middle Aged , Molecular Sequence Data , Peptides/immunology , T-Lymphocytes, Regulatory/immunology , Vaccination , Vaccines, Synthetic/administration & dosage
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