Enumeration of Functional T-Cell Subsets by Fluorescence-Immunospot Defines Signatures of Pathogen Burden in Tuberculosis

IFN-γ and IL-2 cytokine-profiles define three functional T-cell subsets which may correlate with pathogen load in chronic intracellular infections. We therefore investigated the feasibility of the immunospot platform to rapidly enumerate T-cell subsets by single-cell IFN-γ/IL-2 cytokine-profiling and establish whether immunospot-based T-cell signatures distinguish different clinical stages of human tuberculosis infection.We used fluorophore-labelled anti-IFN-γ and anti-IL-2 antibodies with digital overlay of spatially-mapped colour-filtered images to enumerate dual and single cytokine-secreting M. tuberculosis antigen-specific T-cells in tuberculosis patients and in latent tuberculosis infection (LTBI). We validated results against established measures of cytokine-secreting T-cells.Fluorescence-immunospot correlated closely with single-cytokine enzyme-linked-immunospot for IFN-γ-secreting T-cells and IL-2-secreting T-cells and flow-cytometry-based detection of dual IFN-γ/IL-2-secreting T-cells. The untreated tuberculosis signature was dominated by IFN-γ-only-secreting T-cells which shifted consistently in longitudinally-followed patients during treatment to a signature dominated by dual IFN-γ/IL-2-secreting T-cells in treated patients. The LTBI signature differed from active tuberculosis, with higher proportions of IL-2-only and IFN-γ/IL-2-secreting T-cells and lower proportions of IFN-γ-only-secreting T-cells.Fluorescence-immunospot is a quantitative, accurate measure of functional T-cell subsets; identification of cytokine-signatures of pathogen burden, distinct clinical stages of M. tuberculosis infection and long-term immune containment suggests application for treatment monitoring and vaccine evaluation

Reemergence of Gentamicin-Susceptible Strains of Methicillin-Resistant Staphylococcus aureus in France: a Phylogenetic Approach

The reemergence of gentamicin-susceptible (Gen(s)) methicillin-resistant Staphylococcus aureus (MRSA) isolates in France between 1992 and 1996 was investigated using a phylogenetic approach (multiprimer randomly amplified polymorphic DNA typing). Eighty-six percent (65 of 85) of the French strains were grouped into one phylogenetic cluster within which all but one Gen(s) strain were grouped into a subcluster. Thus, the reemergence of Gen(s) MRSA strains in France was likely due to the spread of one specific clone which belonged to a cluster comprising most French gentamicin-resistant (Gen(r)) strains. This suggests that the Gen(s) clone has emerged from a Gen(r) strain of this cluster

Generation of induced pluripotent stem cells (IRMBi001-A) from an Alzheimer's disease patient carrying a G217D mutation in the PSEN1 gene

Induced pluripotent stem cells (iPSC) were generated from skin fibroblasts obtained from a 50 year-old patient suffering from Alzheimer's disease and carrying a G217D causal mutation on presenilin 1 (PSEN1). iPSCs were obtained following reprogramming using the integration-free Sendai Virus system which allows expression of the Yamanaka factors. Verification of their pluripotency was achieved by demonstrating the expression of pluripotency markers and their differentiation potential into the three primary germ layers. iPS cells carry the patient G217D mutation and present a normal karyotype. The reported PS1-G217D iPSC line may be used to model and study human AD pathology in vitro

Generation of induced pluripotent stem cells (iPSCs) IRMBi002-A from an Alzheimer's disease patient carrying a D694N mutation in the APP gene

International audienceInduced pluripotent stem cells (iPSC) were generated from skin fibroblasts obtained from a 58 year-old woman suffering from Alzheimer's disease and carrying a D694N mutation on Amyloid precursor protein (APP). Fibroblasts were reprogrammed into iPSC using the integration-free Sendai Virus which allows the expression of the Yamanaka factors. Verification of their pluripotency was achieved by demonstrating the expression of pluripotency markers and their differentiation potential into the three primary germ layers. The cells have the corresponding mutation and present a normal karyotype. The reported APP-D694N iPSC line may be used to model and study human AD pathology in vitro