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Tiwari RP, Hattikudur NS, Bharmal RN, Kartikeyan S, Deshmukh NM, Bisen PS. Modern approaches to a rapid diagnosis of tuberculosis: promises and challenges ahead. Tuberculosis (Edinb) 2006; 87:193-201. [PMID: 17029964 DOI: 10.1016/j.tube.2006.07.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 06/05/2006] [Accepted: 07/20/2006] [Indexed: 11/20/2022]
Abstract
The limitations of the conventional methods for diagnosing tuberculosis have spurred multi-faceted research activities in this field throughout the world. Chromatographic methods appear promising but may not be widely available in the developing countries. Immuno-diagnostic methods using combinations ("cocktails") of antigens have high sensitivity and specificity and can easily be applied in the peripheral laboratories and in the field settings. Though expensive, molecular methods for diagnosis of tuberculosis have advantages of speed, sensitivity, and specificity. Adequate training of the eligible personnels in molecular methods and prevention of laboratory-dependent contamination may help reduce false positive results. Although, there are no clear guidelines, so far on how to make out the best from the gene amplification methods, yet their use may be encouraged with adequate quality controls, because of the inherent ingenuity and promises of these methods. Phage-based molecular methods provide rapid results in susceptibility tests for anti-tubercular drugs. In future, many sophisticated techniques are expected to hit the market for a rapid diagnosis of tuberculosis. In the developing countries, it is necessary to evaluate availability of suitable infrastructure and trained personnels before adopting modern diagnostic methods.
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Affiliation(s)
- Ram Pramod Tiwari
- Diagnostic Division, Nicholas Piramal India Limited, Pawane, Navi Mumbai 400 705, India
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4
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Sutcliffe IC, Harrington DJ. Lipoproteins ofMycobacterium tuberculosis: an abundant and functionally diverse class of cell envelope components. FEMS Microbiol Rev 2004; 28:645-59. [PMID: 15539077 DOI: 10.1016/j.femsre.2004.06.002] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2003] [Revised: 03/16/2004] [Accepted: 06/18/2004] [Indexed: 11/24/2022] Open
Abstract
Mycobacterium tuberculosis remains the predominant bacterial scourge of mankind. Understanding of its biology and pathogenicity has been greatly advanced by the determination of whole genome sequences for this organism. Bacterial lipoproteins are a functionally diverse class of membrane-anchored proteins. The signal peptides of these proteins direct their export and post-translational lipid modification. These signal peptides are amenable to bioinformatic analysis, allowing the lipoproteins encoded in whole genomes to be catalogued. This review applies bioinformatic methods to the identification and functional characterisation of the lipoproteins encoded in the M. tuberculosis genomes. Ninety nine putative lipoproteins were identified and so this family of proteins represents ca. 2.5% of the M. tuberculosis predicted proteome. Thus, lipoproteins represent an important class of cell envelope proteins that may contribute to the virulence of this major pathogen.
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Garg SK, Tiwari RP, Tiwari D, Singh R, Malhotra D, Ramnani VK, Prasad G, Chandra R, Fraziano M, Colizzi V, Bisen PS. Diagnosis of tuberculosis: available technologies, limitations, and possibilities. J Clin Lab Anal 2003; 17:155-63. [PMID: 12938143 PMCID: PMC6807935 DOI: 10.1002/jcla.10086] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rapid diagnosis and treatment are important for preventing transmission of Mycobacterium tuberculosis. However, the diagnosis of tuberculosis continues to pose serious problems, mainly because of difficulties in differentiating between patients with active tuberculosis and those with healed lesions, normal mycobacterium boris BCG (Bacillus Calmette Guerin) vaccinated individuals, and unvaccinated Manteux positives. Physicians still rely on conventional methods such as Ziehl-Neelsen (ZN) staining, fluorochrome staining, sputum culture, gastric lavage, and other non-traditional methods. Although the tuberculin test has aided in the diagnosis of tuberculosis for more than 85 years, its interpretation is difficult because sensitization with nontuberculous mycobacteria leads to false-positive tests. There have been numerous unsuccessful attempts to develop clinically useful serodiagnostic kits for tuberculosis. A number of proteinaceous and nonprotein antigens (such as acyltrehaloses and phenolglycolipids) have been explored from time to time for the development of such assays but they have not proved to be clinically useful. It has been difficult to develop an ELISA utilizing a suitable antigen because M. tuberculosis shares a large number of antigenic proteins with other microorganisms that may or may not be pathogenic. With the advent of molecular biology techniques, there have been significant advances in nucleic acid-based amplification and hybridization, which are helping to rectify existing flaws in the diagnosis of tuberculosis. The detection of mycobacterial DNA in clinical samples by polymerase chain reaction (PCR) is a promising approach for the rapid diagnosis of tuberculous infection. However, the PCR results must be corrected for the presence of inhibitors as well as for DNA contamination. In the modern era of genetics, marked by proteomics and genomics, the day is not far off when DNA chip-based hybridization assays will instantly reveal mycobacterial infections.
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Affiliation(s)
- Sanjay K. Garg
- Department of Biotechnology, Madhav Institute of Technology and Science, Gwalior, India
- Department of Biology, University of Rome Tor‐Vergata, Rome, Italy
| | - R. P. Tiwari
- Department of Biotechnology, Madhav Institute of Technology and Science, Gwalior, India
| | - Dileep Tiwari
- Department of Biotechnology, Madhav Institute of Technology and Science, Gwalior, India
| | - Rupinder Singh
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Dolly Malhotra
- Department of Botany, Motilal Vigyan Mahavidyalaya, Bhopal, India
| | - V. K. Ramnani
- Department of Microbiology and Immunology, Gandhi Medical College, Bhopal, India
| | - G.B.K.S. Prasad
- School of Studies in Biochemistry, Jiwaji University, Gwalior, India
| | - Ramesh Chandra
- Department of Biotechnology, JC Bose Institute of Life Sciences, Bundelkhand University, Jhansi, India
| | - M. Fraziano
- Department of Biology, University of Rome Tor‐Vergata, Rome, Italy
| | - V. Colizzi
- Department of Biology, University of Rome Tor‐Vergata, Rome, Italy
- International Center for Aids & Emerging and Reemerging Infections, IRCCS, L. Spallanzani Institute, Rome, Italy
| | - Prakash S. Bisen
- Department of Biotechnology, Madhav Institute of Technology and Science, Gwalior, India
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Abstract
The epidemiological evidence for the proposal that early life immune deviation is the principal mechanism by which microbial agents prevent the development of atopy has been reviewed. Seven criteria are proposed which should ideally be fulfilled. The majority of studies only fulfill two or three criteria. For mycobacteria, measles and respiratory viruses there are studies that demonstrate a significant increase in atopy or allergic disease. Parasite infections, which provide a strong TH2 stimulus, are associated with reduced rather than enhanced allergen sensitization. The available epidemiological evidence does not provide support for a mechanism of early life immune deviation. The principal environmental influences on atopic disease are likely to occur throughout life and involve interactions between microbes and other non-infective and lifestyle factors.
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Affiliation(s)
- Andrew Kemp
- Department of Immunology, Royal Children's Hospital, Murdoch Children's Research Institute, Melbourne, Australia.
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Herrmann JL, Delahay R, Gallagher A, Robertson B, Young D. Analysis of post-translational modification of mycobacterial proteins using a cassette expression system. FEBS Lett 2000; 473:358-62. [PMID: 10818240 DOI: 10.1016/s0014-5793(00)01553-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A recombinant expression system was developed to analyse sequence determinants involved in O-glycosylation of proteins in mycobacteria. By expressing peptide sequences corresponding to known glycosylation sites within a chimeric lipoprotein construct, amino acids flanking modified threonine residues were found to have an important influence on glycosylation. The expression system was used to screen mycobacterial sequences selected using a neural network (NetOglyc) trained on eukaryotic O-glycoproteins. Evidence of glycosylation was obtained for eight of 11 proteins tested. The results suggest that sites involved in O-glycosylation of mycobacterial and eukaryotic proteins share similar structural features.
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Affiliation(s)
- J L Herrmann
- Department of Infectious Diseases and Microbiology, Imperial College School of Medicine, St. Mary's Campus, Norfolk Place, W2 1PG, London, UK.
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Abstract
Identification and characterization of mycobacterial adhesins and complementary host receptors required for colonization and dissemination of mycobacteria in host tissues are needed for a more complete understanding of the pathogenesis of diseases caused by these bacteria and for the development of effective vaccines. Previous investigations have demonstrated that a 28-kDa heparin-binding mycobacterial surface protein, HBHA, can agglutinate erythrocytes and promote mycobacterial aggregation in vitro. In this study, further molecular and biochemical analysis of HBHA demonstrates that it has three functional domains: a transmembrane domain of 18 amino acids residing near the N terminus, a large domain of 81 amino acids consistent with an alpha-helical coiled-coil region, and a Lys-Pro-Ala-rich C-terminal domain that mediates binding to proteoglycans. Using His-tagged recombinant HBHA proteins and nickel chromatography we demonstrate that HBHA polypeptides which contain the coiled-coil region form multimers. This tendency to oligomerize may be responsible for the induction of mycobacterial aggregation since a truncated N-terminal HBHA fragment containing the coiled-coil domain promotes mycobacterial aggregation. Conversely, a truncated C-terminal HBHA fragment which contains Lys-Pro-Ala-rich repeats binds to the proteoglycan decorin. These results indicate that HBHA contains at least three distinct domains which facilitate intercalation into surface membranes, promote bacterium-bacterium interactions, and mediate the attachment to sulfated glycoconjugates found in host tissues.
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Affiliation(s)
- G Delogu
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA
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Mahenthiralingam E, Marklund BI, Brooks LA, Smith DA, Bancroft GJ, Stokes RW. Site-directed mutagenesis of the 19-kilodalton lipoprotein antigen reveals No essential role for the protein in the growth and virulence of Mycobacterium intracellulare. Infect Immun 1998; 66:3626-34. [PMID: 9673242 PMCID: PMC108395 DOI: 10.1128/iai.66.8.3626-3634.1998] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/1997] [Accepted: 05/11/1998] [Indexed: 02/08/2023] Open
Abstract
The mycobacterial 19-kilodalton antigen (19Ag) is a highly expressed, surface-associated glycolipoprotein which is immunodominant in infected patients and has little homology with other known proteins. To investigate the pathogenic significance of the 19Ag, site-directed mutagenesis of the Mycobacterium intracellulare 19Ag gene was carried out by using a suicide vector-based strategy. Allelic replacement of the 19Ag gene of a mouse-avirulent M. intracellulare strain, 1403, was achieved by double-crossover homologous recombination with a gentamicin resistance gene-mutated allele. Unfortunately, an isogenic 19Ag was not achievable in the mouse-virulent strain, D673. However, a 19Ag mutant was successfully constructed in M. intracellulare FM1, a chemically mutagenized derivative of strain D673. FM1 was more amenable to genetic manipulation and susceptible to site-directed mutagenesis of the 19Ag gene yet retained the virulent phenotype of the parental strain. No deleterious effects of 19Ag gene mutation were observed during in vitro growth of M. intracellulare. Virulence assessment of the isogenic 19Ag mutants in a mouse infection model demonstrated that the antigen plays no essential role in the growth of M. intracellulare in vivo. Site-directed mutagenesis of the 19Ag gene demonstrated that it plays no essential role in growth and pathogenicity of M. intracellulare; however, the exact nature of its biological function remains unknown.
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Affiliation(s)
- E Mahenthiralingam
- Division of Infectious and Immunological Diseases, B.C. Children's Hospital, University of British Columbia, Vancouver, Canada
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Triccas JA, Winter N, Roche PW, Gilpin A, Kendrick KE, Britton WJ. Molecular and immunological analyses of the Mycobacterium avium homolog of the immunodominant Mycobacterium leprae 35-kilodalton protein. Infect Immun 1998; 66:2684-90. [PMID: 9596734 PMCID: PMC108256 DOI: 10.1128/iai.66.6.2684-2690.1998] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The analysis of host immunity to mycobacteria and the development of discriminatory diagnostic reagents relies on the characterization of conserved and species-specific mycobacterial antigens. In this report, we have characterized the Mycobacterium avium homolog of the highly immunogenic M. leprae 35-kDa protein. The genes encoding these two proteins were well conserved, having 82% DNA identity and 90% identity at the amino acid level. Moreover both proteins, purified from the fast-growing host M. smegmatis, formed multimeric complexes of around 1000 kDa in size and were antigenically related as assessed through their recognition by antibodies and T cells from M. leprae-infected individuals. The 35-kDa protein exhibited significant sequence identity with proteins from Streptomyces griseus and the cyanobacterium Synechoccocus sp. strain PCC 7942 that are up-regulated under conditions of nutrient deprivation. The 67% amino acid identity between the M. avium 35-kDa protein and SrpI of Synechoccocus was spread across the sequences of both proteins, while the homologous regions of the 35-kDa protein and the P3 sporulation protein of S. griseus were interrupted in the P3 protein by a divergent central region. Assessment by PCR demonstrated that the gene encoding the M. avium 35-kDa protein was present in all 30 M. avium clinical isolates tested but absent from M. intracellulare, M. tuberculosis, or M. bovis BCG. Mice infected with M. avium, but not M. bovis BCG, developed specific immunoglobulin G antibodies to the 35-kDa protein, consistent with the observation that tuberculosis patients do not recognize the antigen. Strong delayed-type hypersensitivity was elicited by the protein in guinea pigs sensitized with M. avium.
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Affiliation(s)
- J A Triccas
- Centenary Institute of Cancer Medicine and Cell Biology, Newtown, New South Wales 2042, Australia
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Abou-Zeid C, Gares MP, Inwald J, Janssen R, Zhang Y, Young DB, Hetzel C, Lamb JR, Baldwin SL, Orme IM, Yeremeev V, Nikonenko BV, Apt AS. Induction of a type 1 immune response to a recombinant antigen from Mycobacterium tuberculosis expressed in Mycobacterium vaccae. Infect Immun 1997; 65:1856-62. [PMID: 9125572 PMCID: PMC175231 DOI: 10.1128/iai.65.5.1856-1862.1997] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
A 19-kDa lipoprotein from Mycobacterium tuberculosis was expressed as a recombinant antigen in the nonpathogenic mycobacterial host strain M. vaccae. Immunization of mice with the recombinant M. vaccae resulted in induction of a strong type 1 immune response to the 19-kDa antigen, characterized by immunoglobulin G2a (IgG2a) antibodies and gamma interferon (IFN-gamma) production by splenocytes. Immunization with the same antigen in incomplete Freund's adjuvant induced a strong IgG1 response with only low levels of IFN-gamma. Subsequent intravenous and aerosol challenges of immunized mice with virulent M. tuberculosis demonstrated no evidence of protection associated with the response to the 19-kDa antigen; in fact, the presence of the recombinant 19-kDa antigen abrogated the limited protection conferred by M. vaccae (vector control). The recombinant M. vaccae system is a convenient approach to induction of type 1 responses to M. tuberculosis antigens. However, the unexpected reduction in protective efficacy of M. vaccae expressing the 19-kDa antigen highlights the complexity of testing recombinant subunit vaccines and the need for a better understanding of the immune mechanisms required for effective vaccination against tuberculosis.
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MESH Headings
- Administration, Oral
- Animals
- Antibodies, Bacterial/analysis
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Biological Assay
- Blotting, Western
- Disease Susceptibility/immunology
- Electrophoresis, Polyacrylamide Gel
- Enzyme-Linked Immunosorbent Assay
- Female
- Freund's Adjuvant/immunology
- Gene Expression Regulation, Bacterial
- Genetic Predisposition to Disease
- Hypersensitivity, Immediate/immunology
- Immunization/methods
- Immunoglobulin G/biosynthesis
- Immunoglobulin G/immunology
- Interferon-gamma/biosynthesis
- Interferon-gamma/immunology
- Lipoproteins/genetics
- Lipoproteins/immunology
- Mice
- Mice, Inbred C57BL
- Mycobacterium/genetics
- Mycobacterium Infections/genetics
- Mycobacterium Infections/immunology
- Mycobacterium tuberculosis/genetics
- Mycobacterium tuberculosis/immunology
- Plasmids
- Recombinant Proteins/immunology
- Recombination, Genetic
- Spleen/immunology
- Tuberculosis, Splenic/genetics
- Tuberculosis, Splenic/immunology
- Tuberculosis, Splenic/prevention & control
- Vaccines, Synthetic/adverse effects
- Vaccines, Synthetic/immunology
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Affiliation(s)
- C Abou-Zeid
- Department of Medical Microbiology, Imperial College School of Medicine at St. Mary's, London, United Kingdom.
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12
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Thangaraj HS, Bull TJ, De Smet KA, Hill MK, Rouse DA, Moreno C, Ivanyi J. Duplication of genes encoding the immunodominant 38 kDa antigen in Mycobacterium intracellulare. FEMS Microbiol Lett 1996; 144:235-40. [PMID: 8900068 DOI: 10.1111/j.1574-6968.1996.tb08536.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mycobacterium avium is a causative agent of mycobacterioses in systemically immunocompromised individuals, whereas Mycobacterium intracellulare is responsible for causing infections in relatively immunocompetent hosts. In an attempt to identify components that could be involved in virulence, we characterised the 38 kDa-encoding gene of M intracellulare that is absent in M. avium. This antigen cross reacts immunologically with a major 38 kDa antigen of M. tuberculosis, and both antigens are homologues of the phosphate transport subunit S (PstS) of the pst complex of Escherichia coli. Unlike the M. tuberculosis complex the M. intracellulare coding gene was found to be duplicated. We also identified and characterised other pst genes that may constitute an operon. Considering that multiple isoforms of PstS are present in mycobacteria the possible role of pstS1 genes for pathogenesis is discussed.
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Affiliation(s)
- H S Thangaraj
- M.R.C. Tuberculosis and Related Infections, Unit, Hammersmith Hospital,London, UK.
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Lathigra R, Zhang Y, Hill M, Garcia MJ, Jackett PS, Ivanyi J. Lack of production of the 19-kDa glycolipoprotein in certain strains of Mycobacterium tuberculosis. Res Microbiol 1996; 147:237-49. [PMID: 8763611 DOI: 10.1016/0923-2508(96)81384-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The 19-kDa glycolipoprotein of Mycobacterium tuberculosis (PT19) is a prominent antigen recognized by both T cells and antibodies from tuberculosis patients. We report here that two strains, I2646 and S1, when grown either in bacteriological culture or during infection of mice, do not produce this constituent, as judged by ELISA and Western blot assays. Southern blot analysis of the chromosomal DNA showed that both strains displayed the restriction fragment as in H37Rv DNA, suggesting the lack of gross gene alterations. Sequence analysis revealed multiple microlesions including small deletions, point mutations and nucleotide insertions, leading to either premature termination or alteration of open reading frame in both strains. Transformation of both mutant strains with the wild-type gene on a multicopy plasmid resulted in overproduction of native PT19. Infection of mice suggested that the I2646 is of low virulence and that the transformant-producing native PT19 exhibited higher virulence, as assessed by viable counts and gross lesions in the infected organs. The mechanisms and significance of the lack of PT19 production in certain M. tuberculosis strains is discussed.
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Affiliation(s)
- R Lathigra
- Royal Postgraduate Medical School, London
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Hewinson RG, Harris DP, Whelan A, Russell WP. Secretion of the mycobacterial 19-kilodalton protein by Escherichia coli, a novel method for the purification of recombinant mycobacterial antigens. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1996; 3:23-9. [PMID: 8770499 PMCID: PMC170242 DOI: 10.1128/cdli.3.1.23-29.1996] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have reported previously (R.G. Hewinson and W.P. Russell, J. Gen. Microbiol. 139:1253-1259, 1993) the secretion by Escherichia coli of a recombinant form of the immunogenic protein MPB70 of Mycobacterium bovis when the protein is translated from its native initiation codon. N-terminal sequence analysis of the purified protein revealed that the signal peptide of MPB70 was cleaved by an endopeptidase of E. coli at the same cleavage site as reported for the protein in M. bovis. Since both the B- and T-cell antigenicities of the purified recombinant protein were similar to that of the native protein, the 19-kDa antigen of M. bovis was used as a model to test whether the signal peptide of MPB70 could direct the secretion of heterologous proteins in E. coli and whether antigen produced in this way retained antigenicity superior to that of recombinant protein produced as a fusion to glutathione-S-transferase. A chimeric protein was produced in which the signal peptide of MPB70 was fused to the 19-kDa antigen of M. bovis at amino acid residue 23. This chimeric protein was found to be secreted into the periplasm and culture medium of recombinant E. coli, and the signal peptide was cleaved by an endopeptidase of E. coli during secretion. Secretion of the 19-kDa antigen facilitated purification of the antigen by two-stage preparative electrophoresis which gave yields of 2.5 mg of purified, soluble 19-kDa antigen from 2.5 g (wet weight) of E. coli. Antigen purified in this way retained both B- and T-cell antigenicities. Moreover, the nonspecific mitogenic activity of the purified 19-kDa antigen was low, while the magnitude of the T-cell response induced by the purified antigen was considerably higher than that observed with purified antigen produced as a fusion protein with glutathione-S-transferase.
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Affiliation(s)
- R G Hewinson
- Bacteriology Department, Central Veterinary Laboratory, Weybridge, Addlestone, Surrey, United Kingdom
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Rouse DA, Morris SL. Molecular mechanisms of isoniazid resistance in Mycobacterium tuberculosis and Mycobacterium bovis. Infect Immun 1995; 63:1427-33. [PMID: 7890405 PMCID: PMC173170 DOI: 10.1128/iai.63.4.1427-1433.1995] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Genetic and biochemical studies have suggested a link between reduced catalase activity and resistance to isoniazid in Mycobacterium tuberculosis. In this study, we examined the molecular mechanisms of resistance to isoniazid with six in vitro mutants of the M. tuberculosis complex (Mycobacterium bovis and M. tuberculosis). Five of six mutants resistant to isoniazid were negative by catalase assays. Immunoblot analyses using a polyclonal antibody against the katG gene product (catalase-peroxidase) demonstrated that the enzyme is not produced in four of these isoniazid-resistant strains. A complete deletion of the katG gene was detected in only one of these isoniazid-resistant M. tuberculosis complex strains by Southern blot analyses. In two other resistant strains, partial deletions of the katG gene were identified. A point mutation which resulted in the insertion of a termination codon in the katG coding sequence caused a catalase-negative phenotype in a fourth strain. Of the two resistant strains which produce the enzyme, one was shown to be negative by a catalase assay. Single-stranded conformational polymorphism and DNA sequence analyses identified a mutation in the katG gene of this strain which may contribute to reduced enzymatic activity and subsequent isoniazid resistance. These data demonstrate that genetic alterations to the katG gene other than complete deletions are prevalent and may contribute significantly to the number of cases of isoniazid-resistant tuberculosis.
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Affiliation(s)
- D A Rouse
- Laboratory of Mycobacteria, Food and Drug Administration, Bethesda, Maryland 20892
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Affiliation(s)
- I C Sutcliffe
- Department of Oral Biology, Dental School, University of Newcastle upon Tyne, United Kingdom
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Harris DP, Vordermeier HM, Brett SJ, Pasvol G, Moreno C, Ivanyi J. Epitope specificity and isoforms of the mycobacterial 19-kilodalton antigen. Infect Immun 1994; 62:2963-72. [PMID: 7516315 PMCID: PMC302905 DOI: 10.1128/iai.62.7.2963-2972.1994] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The topography and specificity of B- and T-cell stimulatory epitopes from the 19-kDa protein of Mycobacterium tuberculosis were investigated by using overlapping synthetic peptides. Murine antisera identified two cryptic epitopes (residues 11 to 30 and 61 to 80) and one species-specific immunodominant epitope (residues 140 to 159). Immunoglobulins G1 and G2a antibody isotypes varied for the respective peptide immunogens but without relationship to the T-cell cytokine profiles which were characterized by high gamma interferon and low interleukin 5 levels. Antisera to recombinant M. tuberculosis 19-kDa protein (rGST-19) cross-reacted with homologous proteins of similar size from organisms of the Mycobacterium avium-intracellulare complex. Two-dimensional gel electrophoresis revealed differences in the number, relative mobility, and charge of isoforms of the 19-kDa protein, possibly reflecting posttranslational modifications. The immunodominant T-cell epitope from the M. tuberculosis 19-kDa protein (residues 61 to 80) and the corresponding peptide sequence from Mycobacterium avium subsp. intracellulare (residues 64 to 83), differing at five residues, were both recognized in a genetically permissive manner. Peptides 61-80 and 64-83 stimulated cross-reactive responses in BALB/c (H-2d) mice, while in the C57BL/10 (H-2b) strain, responses to peptide 61-80 were species specific. In purified protein derivative-positive healthy individuals, the M. avium subsp. intracellulare peptide stimulated stronger responses than did the M. tuberculosis peptide, whereas patients with active tuberculosis had enhanced in vitro T-cell responses to both peptides.
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Affiliation(s)
- D P Harris
- MRC Clinical Sciences Centre, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
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18
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Nair J, Rouse DA, Bai GH, Morris SL. The rpsL gene and streptomycin resistance in single and multiple drug-resistant strains of Mycobacterium tuberculosis. Mol Microbiol 1993; 10:521-7. [PMID: 7968530 DOI: 10.1111/j.1365-2958.1993.tb00924.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The recent emergence of indolent and rapidly fatal drug-resistant strains of Mycobacterium tuberculosis has renewed interest in defining the molecular mechanisms of drug resistance in the tubercle bacilli. In this report, we have examined the mechanism of resistance to streptomycin (Sm) in M. tuberculosis through the cloning and nucleotide sequence analysis of the gene encoding the ribosomal S12 protein (rpsL gene) from streptomycin-resistant strains and their streptomycin-sensitive parental strains. We have demonstrated that five singly SmR M. tuberculosis strains and an SmR isolate that has reduced sensitivity to multiple antibiotics have identical point mutations at codon 43 of the rpsL gene. Mutations at this same site confer SmR in Escherichia coli. In contrast, two other multiple drug-resistant M. tuberculosis strains that are resistant to Sm have rpsL genes that have the same nucleotide sequence as their drug-sensitive parent strains, suggesting that different resistance mechanisms are involved in these strains.
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Affiliation(s)
- J Nair
- Laboratory of Mycobacteria, United States Food and Drug Administration, Bethesda, Maryland 20892
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19
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Mackall JC, Bai GH, Rouse DA, Armoa GR, Chuidian F, Nair J, Morris SL. A comparison of the T cell delayed-type hypersensitivity epitopes of the 19-kD antigens from Mycobacterium tuberculosis and Myco. intracellulare using overlapping synthetic peptides. Clin Exp Immunol 1993; 93:172-7. [PMID: 7688674 PMCID: PMC1554851 DOI: 10.1111/j.1365-2249.1993.tb07961.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mycobacterial disease remains a serious international public health concern. Improved methods to rapidly and specifically detect mycobacterial infections would greatly enhance clinical management of these diseases. To define species-specific T cell epitopes that may be useful for the immunodiagnosis of mycobacterial infections, polymerized synthetic peptides from the 19-kD Mycobacterium tuberculosis and Myco. intracellulare protein homologues were tested in guinea pig DTH assays. Five Myco. tuberculosis and eight Myco. intracellulare peptides evoked skin test responses. Although all of the active Myco. tuberculosis and seven of the Myco. intracellulare peptides elicited non-specific DTH reactions, the peptide IN13 induced a Myco. intracellulare-specific skin test reaction, and thus represents a specific Myco. intracellulare T cell DTH epitope. This result suggests that the development of monospecific peptide-based immunodiagnostic reagents may be feasible for future clinical use.
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Affiliation(s)
- J C Mackall
- Laboratory of Mycobacteria, US FDA, Rockville, MD 20852-1448
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Nair J, Rouse DA, Morris SL. Nucleotide sequence analysis and serologic characterization of a 27-kilodalton Mycobacterium intracellulare lipoprotein. Infect Immun 1993; 61:1074-81. [PMID: 8432589 PMCID: PMC302841 DOI: 10.1128/iai.61.3.1074-1081.1993] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Disseminated mycobacteremia resulting from Mycobacterium avium-Mycobacterium intracellulare complex (MAC) infections frequently contribute to the morbidity and mortality seen in AIDS patients. To better understand the immunopathology of MAC disease and to identify molecules that may have potential diagnostic and vaccine utility, an immunoreactive M. intracellulare protein (MI43) and the gene encoding this antigen were characterized. Southern blot hybridizations demonstrated that MI43 gene probes reacted only with genomic DNA from M. intracellulare, M. avium, and Mycobacterium asiaticum and not with DNA isolated from 11 other mycobacterial species. Nucleotide sequence analysis showed that the MI43 gene encodes a 27-kDa protein which contains a consensus bacterial lipoprotein processing sequence. Detergent-phase separations and metabolic labeling with [3H]palmitate also suggested that MI43 is a lipoprotein. Serological assays demonstrated that recombinant MI43 fusion proteins react with sera from M. avium-infected mice, sera from patients with MAC disease, and sera from patients with active tuberculosis. These results further suggest that mycobacterial lipoproteins are important immunogens that should be considered in the development of improved mycobacterial vaccines and diagnostic reagents.
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Affiliation(s)
- J Nair
- Laboratory of Mycobacteria, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892
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Garbe T, Harris D, Vordermeier M, Lathigra R, Ivanyi J, Young D. Expression of the Mycobacterium tuberculosis 19-kilodalton antigen in Mycobacterium smegmatis: immunological analysis and evidence of glycosylation. Infect Immun 1993; 61:260-7. [PMID: 8418047 PMCID: PMC302713 DOI: 10.1128/iai.61.1.260-267.1993] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The gene encoding a 19-kDa antigen from Mycobacterium tuberculosis was expressed as a recombinant protein in the rapid-growing species Mycobacterium smegmatis. The recombinant antigen was expressed at a level approximately ninefold higher than in M. tuberculosis and, like the native antigen, was found in the pellet fraction after high-speed centrifugation of bacterial extracts. The 19-kDa antigen in crude bacterial extracts, and the purified recombinant antigen, bound strongly to concanavalin A, indicating the possibility of posttranslational glycosylation. The recombinant antigen stimulated T-cell proliferation in vitro when added to assays either in the form of whole recombinant bacteria or as a purified protein. Homologous expression of mycobacterial antigens in a rapid-growing mycobacterial host may be particularly useful for the immunological characterization of proteins which are subject to posttranslational modification.
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Affiliation(s)
- T Garbe
- Medical Research Council Tuberculosis and Related Infections Unit, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
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