Ineffective phagocytosis of amyloid-beta by macrophages of Alzheimer's disease patients.

The defective clearance of amyloid-beta (Abeta) in the brain of Alzheimer's disease (AD) patients is unexplained. The immunohistochemical studies of the frontal lobe and hippocampus show perivascular and intraplaque infiltration by blood-borne macrophages containing intracellular Abeta but only inefficient clearance of beta deposits. Neurons and neuronal nuclei, respectively, express interleukin-1beta and the chemokine RANTES, which could induce the inflammatory cell infiltration.

Cytomegalovirus and Epstein-Barr virus DNA transcription in endodontic symptomatic lesions.

Objectives: Productive Herpesviridae infections are implicated in the etio-pathogenesis of aggressive periodontitis. However, virtually nothing is known about a possible role of herpesviruses in pulpal and periapical pathosis. This study employed a cDNA analysis to determine transcription of human cytomegalovirus (HCMV), Epstein-Barr virus (EBV) and herpes simplex virus (HSV) in 14 recalcitrant periapical lesions and in 2 periapical healthy control sites.

Histamine blocks interleukin 2 (IL-2) gene expression and regulates IL-2 receptor expression.

Histamine inhibited the proliferative response of human peripheral blood mononuclear cells (PBMC) to the T cell mitogen Phytohemagglutinin-P (PHA-P) in a dose-dependent fashion. This inhibition was mediated via the H2 receptor since cimetidine, a known H2 antagonist, removed the inhibition, whereas the addition of the H1 antagonist Diphenhydramine did not. Inhibition occurred during the inductive phase of the cell cycle, since histamine added 24 hours after PHA-P stimulation had no effect on subsequent T cell proliferation, and was attributable to inhibition of interleukin-2 (IL-2) gene expression.

Purification of human interleukin 2 produced from normal human peripheral blood mononuclear cells.

We have developed a simple protocol for the routine purification of essentially homogeneous human interleukin 2. The procedures applied include ammonium sulfate precipitation, ACA-54 gel filtration, ultrafiltration and chromatofocusing. The product has a molecular weight of 14 000, as determined by electrophoretic mobility, and is free of interleukin 1, interferon, granulocyte and monocyte stimulating factors, B cell growth factor and phytohemagglutinin.

1,25-Dihydroxyvitamin D3 suppresses human T helper/inducer lymphocyte activity in vitro.

The active form of vitamin D3, 1 alpha,25-dihydroxyvitamin D3 (1,25-(OH)2-D3), suppresses in vitro immunoglobulin (Ig) production by activated peripheral blood mononuclear cells (PBM) from normal human subjects by inhibiting T helper/inducer TH cell activity. Normal PBM were fractionated into B, TH and T suppressor/cytotoxic (Ts) cells by fluorescence-activated cell sorting techniques. The resultant subsets were activated with mitogens and were cultured in the presence or absence of a receptor-saturating concentration of 1,25-(OH)2-D3.