Phenotypic Studies of Natural Killer Cell Subsets in Human Transporter Associated with Antigen Processing Deficiency

Peripheral blood natural killer (NK) cells from patients with transporter associated with antigen processing (TAP) deficiency are hyporesponsive. The mechanism of this defect is unknown, but the phenotype of TAP-deficient NK cells is almost normal. However, we noticed a high percentage of CD56bright cells among total NK cells from two patients. We further investigated TAP-deficient NK cells in these patients and compared them to NK cells from two other TAP-deficient patients with no clinical symptoms and to individuals with chronic inflammatory diseases other than TAP deficiency (chronic lung diseases or vasculitis). Peripheral blood mononuclear cells isolated from venous blood were stained with fluorochrome-conjugated antibodies and the phenotype of NK cells was analyzed by flow cytometry. In addition, 51Chromium release assays were performed to assess the cytotoxic activity of NK cells. In the symptomatic patients, CD56bright NK cells represented 28% and 45%, respectively, of all NK cells (higher than in healthy donors). The patients also displayed a higher percentage of CD56dimCD16− NK cells than controls. Interestingly, this unusual NK cell subtype distribution was not found in the two asymptomatic TAP-deficient cases, but was instead present in several of the other patients. Over-expression of the inhibitory receptor CD94/NKG2A by TAP-deficient NK cells was confirmed and extended to the inhibitory receptor ILT2 (CD85j). These inhibitory receptors were not involved in regulating the cytotoxicity of TAP-deficient NK cells. We conclude that expansion of the CD56bright NK cell subtype in peripheral blood is not a hallmark of TAP deficiency, but can be found in other diseases as well. This might reflect a reaction of the immune system to pathologic conditions. It could be interesting to investigate the relative distribution of NK cell subsets in various respiratory and autoimmune diseases

Les cas déclarés de primo infection tuberculeuse de l'enfant dans le Bas-Rhin du 01/01/2004 au 01/09/2004 (étude descriptive et analytique de 302 cas.)

STRASBOURG-Medecine (674822101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Microbiologie des voies aériennes inférieures de l'enfant porteur d'une infection communautaire.

STRASBOURG-Medecine (674822101) / SudocSudocFranceF

LES HERNIES DIAPHRAGMATIQUES CONGENITALES (ETUDE DE L'EVOLUTION RESPIRATOIRE DE 54 CAS (DES PEDIATRIE))

STRASBOURG-Medecine (674822101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Les kystes lacrymo-nasaux chez le nouveau-né et le nourrisson (une cause rare d'obstruction nasale. A propos de 5 cas)

STRASBOURG-Medecine (674822101) / SudocSudocFranceF

Le déficit d'expression des molécules HLA de classe 1 (à propos de 5 observations et revue de la littérature.)

STRASBOURG-Medecine (674822101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

La dystrophie thoracique de Jeune est-elle toujours asphyxiante ?

STRASBOURG-Medecine (674822101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Les chylothorax congénitaux (à propos de 8 cas en 3 ans)

STRASBOURG-Medecine (674822101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Structure of β-lactoglobulin microgels formed during heating as revealed by small-angle X-ray scattering and light scattering

We have investigated the structure of microgels formed during heating of demineralized β-lactoglobulin (βlg) solutions at pH 5.9 by small-angle X-ray scattering (SAXS) and light scattering. First, unheated βlg solutions were characterized at different pH values between 2.0 and 7.0. At pH 5.9, βlg solutions contain mainly dimers (with a radius of approx. 2 nm), which coexist with a small number of larger oligomers (approx. 4 nm). Afterwards, βlg microgels, which form upon heating, were studied. They exhibit an average hydrodynamic radius around 130 ± 20 nm and an average molar mass around 7 × 10⁸ g mol⁻¹. We followed the temporal evolution of the various structures that form after different heating times using subsequent SAXS measurements of the entire sample, the soluble fraction where the βlg microgels were removed, and the solvent. After an hour of heating at 85 °C the maximum yield of the βlg microgels (ca. 70%) is almost reached. Interestingly, the SAXS data show a correlation peak corresponding to a characteristic distance of about 9 nm, indicating an internal organization of the microgels. During the heating procedure the pH increases from pH 5.9 to approximately 6.6, which is induced by the partial conversion of βlg into βlg microgels that exhibit less buffering capacity than native protein. The remaining soluble fraction consists of native βlg and some small aggregates, whose number increases on the cost of native βlg as heating time proceeds. We propose that the formation of these lower molecular mass aggregates is triggered by the increased pH