Search results for "MYCOBACTERIUM TUBERCULOSIS"
showing 10 items of 159 documents
An anti-inflammatory role for V alpha 14 NK T cells in Mycobacterium bovis bacillus Calmette-Guérin-infected mice.
2003
Abstract The possible contribution of NKT cells to resistance to Mycobacterium tuberculosis infection remains unclear. In this paper we characterized the Vα14 NKT cell population following infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG). BCG infection determined an early expansion of Vα14 NKT cells in liver, lungs, and spleen, which peaked on day 8 and was sustained until day 30. However, an NK1.1+ Vα14 NKT population preferentially producing IFN-γ predominated at an early stage (day 8), which was substituted by an NK1.1− population preferentially producing IL-4 at later stages (day 30). Despite the fact that Vα14 NKT cell-deficient mice eliminated BCG as did control mice…
New amide and dioxopiperazine derivatives from leaves of Breynia nivosa
2017
The first chemical investigation of leaves of Breynia nivosa from Nigeria resulted in the isolation of two new amide derivatives breynivosamides A and B (1 and 2) and two new dioxopiperazine derivatives breynivosines A and B (4 and 5) together with seven known compounds (3, 6-11). The structures of the new compounds were elucidated by 1D, 2D NMR and HRESIMS data as well as by comparison with the literature. All isolated compounds were tested for the cytotoxic and antimicrobial activities. Only cristatin A (6) showed cytotoxicity against the L5178Y mouse lymphoma cell line with an IC50 value of 13.9μM while breynivosamide A (1) exhibited moderate antimicrobial activity against Mycobacterium …
Mycobacterium tuberculosis prosthetic joint infections a case series and literature review
2018
International audience; Objectives - We aimed to characterize diagnosis, management, and outcome of Mycobacterium tuberculosis prosthetic joint infections (PJI).Methods - Cases of M. tuberculosis PJI documented in 7 referral French centers were retrospectively reviewed. Data were collected from medical files on a standardized questionnaire. We performed a literature review using the keywords 'prosthetic joint', and 'tuberculosis'. Results - During years 1997-2016, 13 patients (8 males, 5 females, median age 79 years [range, 60-86]) had documented M. tuberculosis PJI, involving hip (n = 6), knee (n = 6), or shoulder (n = 1). Median time from arthroplasty to diagnosis was 9 years [0.4-20]. Th…
Janus -faced liposomes enhance antimicrobial innate immune response in Mycobacterium tuberculosis infection
2012
We have generated unique asymmetric liposomes with phosphatidylserine (PS) distributed at the outer membrane surface to resemble apoptotic bodies and phosphatidic acid (PA) at the inner layer as a strategy to enhance innate antimycobacterial activity in phagocytes while limiting the inflammatory response. Results show that these apoptotic body-like liposomes carrying PA (ABL/PA) ( i ) are more efficiently internalized by human macrophages than by nonprofessional phagocytes, ( ii ) induce cytosolic Ca 2+ influx, ( iii ) promote Ca 2+ -dependent maturation of phagolysosomes containing Mycobacterium tuberculosis (MTB), ( iv ) induce Ca 2+ -dependent reactive oxygen species (ROS) production, (…
Molecular epidemiology and whole genome sequencing analysis of clinical Mycobacterium bovis from Ghana
2019
[Background]: Bovine tuberculosis (bTB) caused by Mycobacterium bovis is a re-emerging problem in both livestock and humans. The association of some M. bovis strains with hyper-virulence, MDR-TB and disseminated disease makes it imperative to understand the biology of the pathogen.
Ligand‐Specific αβ and γδ T Cell Responses in Childhood Tuberculosis
2000
The alphabeta and gammadelta T cell responses were analyzed in the peripheral blood of children affected by active tuberculosis (TB) and in healthy children who tested positive (PPD+) or negative (PPD-) for purified protein derivative. PPD+ healthy and diseased children responded equally well to PPD in vitro. In contrast, only 18% of PPD+ TB patients responded to peptide p38G derived from the 38-kDa protein of Mycobacterium tuberculosis. Analysis of the whole gammadelta T cell population and of its Vgamma9/Vdelta2 subset showed similar frequencies in PPD+ children with TB and in healthy PPD+ and PPD- children. Vgamma9/Vdelta2 cells from children with TB responded to 5 different phosphoantig…
Clinicopathological profile of gastrointestinal tuberculosis: a multinational ID-IRI study
2020
Data are relatively scarce on gastro-intestinal tuberculosis (GITB). Most studies are old and from single centers, or did not include immunosuppressed patients. Thus, we aimed to determine the clinical, radiological, and laboratory profiles of GITB. We included adults with proven GITB treated between 2000 and 2018. Patients were enrolled from 21 referral centers in 8 countries (Belgium, Egypt, France, Italy, Kazakhstan, Saudi Arabia, UK, and Turkey). One hundred four patients were included. Terminal ileum (n = 46, 44.2%), small intestines except terminal ileum (n = 36, 34.6%), colon (n = 29, 27.8%), stomach (n = 6, 5.7%), and perianal (one patient) were the sites of GITB. One-third of all p…
Analysis of Mycobacterium tuberculosis-Specific CD8 T-Cells in Patients with Active Tuberculosis and in Individuals with Latent Infection
2009
CD8 T-cells contribute to control of Mycobacterium tuberculosis infection, but little is known about the quality of the CD8 T-cell response in subjects with latent infection and in patients with active tuberculosis disease. CD8 T-cells recognizing epitopes from 6 different proteins of Mycobacterium tuberculosis were detected by tetramer staining. Intracellular cytokines staining for specific production of IFN-gamma and IL-2 was performed, complemented by phenotyping of memory markers on antigen-specific CD8 T-cells. The ex-vivo frequencies of tetramer-specific CD8 T-cells in tuberculous patients before therapy were lower than in subjects with latent infection, but increased at four months a…
Reciprocal stimulation of gammadelta T cells and dendritic cells during the anti-mycobacterial immune response.
2004
Gammadelta T cells and dendritic cells (DC) are two distinct cell types of innate immunity that participate in early phases of immune response against Mycobacterium tuberculosis infection. Here we show that a close functional relationship exists between these cell populations. Using an in vitro coculture system, Vgamma1 T cells from Tcrb(-/- )mice were found to be activated by DC infected in vitro with BCG, as indicated by the elevated CD69 expression, IFN-gamma secretion and cytotoxic activity. This activation process was due to a non-cognate mechanism since it required neither cell to cell contact nor interaction between the TCR and a specific antigen, but was mediated by DC-derived IL-12…
Human CD8+ T-cells Recognizing Peptides from Mycobacterium tuberculosis (Mtb) Presented by HLA-E Have an Unorthodox Th2-like, Multifunctional, Mtb In…
2015
Mycobacterial antigens are not exclusively presented to T-cells by classical HLA-class Ia and HLA-class II molecules, but also through alternative antigen presentation molecules such as CD1a/b/c, MR1 and HLA-E. We recently described mycobacterial peptides that are presented in HLA-E and recognized by CD8+ T-cells. Using T-cell cloning, phenotyping, microbiological, functional and RNA-expression analyses, we report here that these T-cells can exert cytolytic or suppressive functions, inhibit mycobacterial growth, yet express GATA3, produce Th2 cytokines (IL-4,-5,-10,-13) and activate B-cells via IL-4. In TB patients, Mtb specific cells were detectable by peptide-HLA-E tetramers, and IL-4 and…