The prevalence and effects of HIV infection among a population of pregnant women needing obstetric intensive care in Cape Town

Includes bibliographical references (leaves 36-37).Care of the critically ill pregnant woman poses exceptional challenges in the intensive care unit and requires the skills of health care providers who have knowledge of the physiological changes of pregnancy as well as specific pregnancy-related disorders in order to achieve optimal management

Mycobacterium tuberculosis antigen 85B and ESAT-6 expressed as a recombinant fusion protein in Mycobacterium smegmatis elicits cell-mediated immune response in a murine vaccination model

This is the post-print version of the final paper published in Molecular Immunology. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.In this study, we investigated the potential molecular and immunological differences of a recombinant fusion protein (Hybrid-1), comprising of the immunodominant antigens Ag85B and ESAT-6 from Mycobacterium tuberculosis, derived from two different expression systems, namely Mycobacterium smegmatis and Escherichia coli. The fusion protein was successfully expressed and purified from both bacterial hosts and analyzed for any host-dependent post-translational modifications that might affect the immunogenicity of the protein. We investigated the immunogenicity of Hybrid-1 expressed in the two host species in a murine vaccination model, together with a reference standard Hybrid-1 (expressed in E. coli) from the Statens Serum Institut. No evidence of any post-translation modification was found in the M. smegmatis-derived Hybrid-1 fusion protein, nor were there any significant differences in the T-cell responses obtained to the three antigens analyzed. In conclusion, the Hybrid-1 fusion protein was successfully expressed in a homologous expression system using M. smegmatis and this system is worth considering as a primary source for vaccination trials, as it provided protein of excellent yield, stability and free from lipopolysaccharide.European TB-VAC consortium and Brunel University

Methylated HBHA Produced in M. smegmatis Discriminates between Active and Non-Active Tuberculosis Disease among RD1-Responders

A challenge in tuberculosis (TB) research is to develop a new immunological test that can help distinguish, among subjects responsive to QuantiFERON TB Gold In tube (QFT-IT), those who are able to control Mtb replication (remote LTBI, recent infection and past TB) from those who cannot (active TB disease). IFN-\u3b3 response to the Heparin-binding-hemagglutinin (HBHA) of Mtb has been associated with LTBI, but the cumbersome procedures of purifying the methylated and immunological active form of the protein from Mtb or M. bovis Bacillus Calmette et Guerin (BCG) have prevented its implementation in a diagnostic test. Therefore, the aim of the present study was to evaluate the IFN-\u3b3 response to methylated HBHA of Mtb produced in M. smegmatis (rHBHAms) in individuals at different stages of TB who scored positive to QFT-IT

T-cell and serological responses to Erp, an exported Mycobacterium tuberculosis protein, in tuberculosis patients and healthy individuals

<p>Abstract</p> <p>Background</p> <p>The identification of antigens able to differentiate tuberculosis (TB) disease from TB infection would be valuable. Cellular and humoral immune responses to Erp (Exported repetitive protein) – a recently identified <it>M. tuberculosis </it>protein – have not yet been investigated in humans and may contribute to this aim.</p> <p>Methods</p> <p>We analyzed the cellular and humoral immune responses to Erp, ESAT-6, Ag85B and PPD in TB patients, in BCG⁺individuals without infection, BCG⁺individuals with latent TB infection (LTBI) and BCG^-controls. We used lymphoproliferation, ELISpot IFN-γ, cytokine production assays and detection of specific human antibodies against recombinant <it>M. tuberculosis </it>proteins.</p> <p>Results</p> <p>We included 22 TB patients, 9 BCG⁺individuals without TB infection, 7 LTBI and 7 BCG^-controls. Erp-specific T cell counts were higher in LTBI than in the other groups. Erp-specific T cell counts were higher in LTBI subjects than TB patients (median positive frequency of 211 SFC/10⁶PBMC (range 118–2000) for LTBI subjects compared to 80 SFC/10⁶PBMC (range 50–191), p = 0.019); responses to PPD and ESAT-6 antigens did not differ between these groups. IFN-γ secretion after Erp stimulation differed between TB patients and LTBI subjects (p = 0.02). Moreover, LTBI subjects but not TB patients or healthy subjects produced IgG3 against Erp.</p> <p>Conclusion</p> <p>The frequencies of IFN-γ-producing specific T cells, the IFN-γ secretion and the production of IgG3 after Erp stimulation are higher in LTBI subjects than in TB patients, whereas PPD and ESAT-6 are not.</p

T-cell immunophenotyping distinguishes active from latent tuberculosis.

BACKGROUND: Changes in the phenotype and function of Mycobacterium tuberculosis (M. tuberculosis)-specific CD4+ and CD8+ T-cell subsets in response to stage of infection may allow discrimination between active tuberculosis and latent tuberculosis infection. METHODS: A prospective comparison of M. tuberculosis-specific cellular immunity in subjects with active tuberculosis and latent tuberculosis infection, with and without human immunodeficiency virus (HIV) coinfection. Polychromatic flow cytometry was used to measure CD4+ and CD8+ T-cell subset phenotype and secretion of interferon γ (IFN-γ), interleukin 2 (IL-2), and tumor necrosis factor α (TNF-α). RESULTS: Frequencies of CD4+ and CD8+ cells secreting IFN-γ-only, TNF-α-only and dual IFN-γ/TNF-α were greater in active tuberculosis vs latent tuberculosis infection. All M. tuberculosis-specific CD4+ subsets, with the exception of IL-2-only cells, switched from central to effector memory phenotype in active tuberculosis vs latent tuberculosis infection, accompanied by a reduction in IL-7 receptor α (CD127) expression. The frequency of PPDspecific CD4+ TNF-α-only-secreting T cells with an effector phenotype accurately distinguished active tuberculosis from latent tuberculosis infection with an area under the curve of 0.99, substantially more discriminatory than measurement of function alone. CONCLUSIONS: Combined measurement of T-cell phenotype and function defines a highly discriminatory biomarker of tuberculosis disease activity. Unlocking the diagnostic and monitoring potential of this combined approach now requires validation in large-scale prospective studies

Effects of Out-of-plane Patterns on Thin Steel Webs: Fabrication Imperfections and Low-Frequency Sinusoids

Thin steel webs can resist large shear forces. When designing large-scale structures, engineers can maximize the shear and flexural strength of steel plate girders by increasing the web depth while minimizing the thickness, which consequently produces slender webs. However, slender webs are susceptible to shear buckling. The objective of this dissertation was to discover, measure, and quantify the relationship between out-of-plane patterns (imperfections) on webs of plate girders and the structural strength via two specific studies: (1) web out-of-flatness imperfections developed during fabrication, and (2) a type of corrugation in the web plate called “low-frequency sinusoids” (LFS). Field measurements, experimental tests, and finite element analyses were the methods employed to meet this objective.The findings of this pioneering research reveal the following: (1) field-measured imperfections exhibit larger shear strength values and do not follow the patterns of the numerical eigenmode shapes, (2) irrespective of the initial imperfection shape and magnitude, the shear buckling behavior in thin webs is a plastic yield mechanism failure penetrating through the web thickness in three stages (elastic stage 1, web mechanism stage 2, and panel mechanism stage 3), (3) the fabrication process of LFS plate girders using the bump and press forming technique will increase the shear strength of plate girders by a maximum of 46% above that of flat webs, and (4) the elastic lateral-torsional buckling (LTB) strength of LFS plate girders with slender webs as compared to flat webs can increase by up to 9%. Overall, this research leads to important conclusions on the effects of imperfections and appropriate methods of their consideration in numerical and experimental studies. The research also enables the development of appropriate fabrication and design specifications for the construction of large-scale structures

Sélection idiotypique et sous-populations de lymphocytes B dans le répertoire preimmun

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe