José Ramón Regueiro

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Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by severe immunologic defects, reduced pigmentation, bleeding tendency, and progressive neurological dysfunction. Most patients present in early childhood and die unless treated by bone marrow transplantation. About 10-15% of patients exhibit a much milder clinical phenotype(More)
Phagocytosis is a pivotal process by which macrophages eliminate microorganisms after recognition by pathogen sensors. Here we unexpectedly found that the self ligand and cell surface receptor SLAM functioned not only as a costimulatory molecule but also as a microbial sensor that controlled the killing of gram-negative bacteria by macrophages. SLAM(More)
Mature CD4(+) and CD8(+) T lymphocytes are believed to build and express essentially identical surface alphabeta T-cell receptor-CD3 (TCR.CD3) complexes. However, TCR.CD3 expression has been shown to be more impaired in CD8(+) cells than in CD4(+) cells when CD3gamma is absent in humans or mice. We have addressed this paradox by performing a detailed(More)
Ataxia telangiectasia (A-T) is an autosomal recessive disorder with a broad range of clinical manifestations and a frequency of 1:40,000-100,000 live births. Epidemiological studies have suggested that A-T heterozygotes are at an elevated risk of breast cancer. ATM mutations occur worldwide over the entire ATM gene, making it difficult to identify(More)
Naturally occurring regulatory T cells (Treg) express high levels of glucocorticoid-induced tumour necrosis factor receptor (GITR). However, studies of the role of GITR in Treg biology has been complicated by the observation that upon activation effector CD4(+) T (Teff) cells also express the receptor. Here, we dissect the contribution of GITR-induced(More)
We have reported the existence of biochemical and conformational differences in the alphabeta T cell receptor (TCR) complex between CD4(+) and CD8(+) CD3gamma-deficient (gamma(-)) mature T cells. In the present study, we have furthered our understanding and extended the observations to primary T lymphocytes from normal (gamma(+)) individuals. Surface(More)
CD8+ T lymphocytes from two unrelated cases of MHC class II deficiency were immortalized in vitro using Herpesvirus saimiri. In both cases, a lack of expression of surface MHC class II molecules was ascertained, whereas variable defects were shown for MHC class I, CD74 (invariant chain) and LAG-3 (an MHC class II ligand). The functional analysis of both H.(More)
Signalling through the TCR is mediated by the cytoplasmic tails of the CD3 complex. Deficiencies in the expression of different CD3 components have lead to dramatic, yet dissimilar, effects on T-cell development and to selective deficits in peripheral T-cell subsets. Recent studies of human patients and animal models with CD3 deficiencies are providing(More)
Activation of the T cell receptor (TCR) by antigen is the key step in adaptive immunity. In the αβTCR, antigen induces a conformational change at the CD3 subunits (CD3 CC) that is absolutely required for αβTCR activation. Here, we demonstrate that the CD3 CC is not induced by antigen stimulation of the mouse G8 or the human Vγ9Vδ2 γδTCR. We find that there(More)