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Naive T lymphocytes travel to T-cell areas of secondary lymphoid organs in search of antigen presented by dendritic cells. Once activated, they proliferate vigorously, generating effector cells that can migrate to B-cell areas or to inflamed tissues. A fraction of primed T lymphocytes persists as circulating memory cells that can confer protection and give,(More)
Using granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin 4 we have established dendritic cell (DC) lines from blood mononuclear cells that maintain the antigen capturing and processing capacity characteristic of immature dendritic cells in vivo. These cells have typical dendritic morphology, express high levels of major(More)
We have previously demonstrated that human peripheral blood low density mononuclear cells cultured in granulocyte/macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4 develop into dendritic cells (DCs) that are extremely efficient in presenting soluble antigens to T ceils. To identify the mechanisms responsible for efficient antigen capture,(More)
T lymphocytes can recognize and be activated by a very small number of complexes of peptide with major histocompatibility complex (MHC) molecules displayed on the surface of antigen-presenting cells (APCs). The interaction between the T-cell receptor (TCR) and its ligand has low affinity and high off-rate. Both findings suggest that an extremely small(More)
Using antigen-specific T cell clones and peptide-pulsed antigen-presenting cells (APCs) we investigated the mechanisms that lead to sustained signaling, known to be required for activation of effector function. Four lines of evidence indicate that the T cell actin cytoskeleton plays a crucial role in T cell activation by antigen-pulsed APCs, but is not(More)
Because ethical restrictions limit in vivo studies of the human hemato-lymphoid system, substitute human to small animal xenotransplantation models have been employed. Existing models, however, sustain only limited development and maintenance of human lymphoid cells and rarely produce immune responses. Here we show that intrahepatic injection of CD34+ human(More)
BACKGROUND Transmission of highly pathogenic avian H5N1 viruses from poultry to humans have raised fears of an impending influenza pandemic. Concerted efforts are underway to prepare effective vaccines and therapies including polyclonal or monoclonal antibodies against H5N1. Current efforts are hampered by the paucity of information on protective immune(More)
Although dispensable, costimulation through CD28 facilitates activation of naïve T lymphocytes. CD28 engagement led to the redistribution and clustering of membrane and intracellular kinase-rich raft microdomains at the site of T cell receptor (TCR) engagements. Although not affecting TCR down-regulation, this process led to higher and more stable tyrosine(More)
The isolation of broadly neutralizing antibodies against influenza A viruses has been a long-sought goal for therapeutic approaches and vaccine design. Using a single-cell culture method for screening large numbers of human plasma cells, we isolated a neutralizing monoclonal antibody that recognized the hemagglutinin (HA) glycoprotein of all 16 subtypes and(More)