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Tuesday, 20 Feb 2018

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Correction The Acute Respiratory Distress Syndrome From Mechanism to Translation CORRECTIONS]

Correction: The Acute Respiratory Distress Syndrome: From Mechanism to Translation [CORRECTIONS]

Peripheral Blood-Derived Virus-Specific Memory Stem T Cells Mature to Functional Effector Memory Subsets with Self-Renewal Potency NOVEL IMMUNOLOGICAL METHODS]

Memory T cells expressing stem cell–like properties have been described recently. The capacity of self-renewal and differentiation into various memory/effector subsets make them attractive for adoptive T cell therapy to combat severe virus infections and tumors. The very few reports on human memory stem T cells (TSCM) are restricted to analyses on polyclonal T cells, but extensive data on Ag-specific TSCM are missing. This might be due to their very low frequency limiting their enrichment and characterization. In this article, we provide functional and phenotypic data on human viral-specific TSCM, defined as CD8+CD45RA+CCR7+CD127+CD95+. Whereas <1% of total T cells express the TSCM phenotype, human CMV–specific TSCM can be detected at frequencies similar to those seen in other subsets, resulting in ~1/10,000 human CMV–specific TSCM. A new virus-specific expansion protocol of sort-purified TSCM reveals both upregulation of various T cell subset markers and preservation of their stem cell phenotype in a significant proportion, indicating both self-renewal and differentiation potency of virus-specific T cells sharing their TCR repertoire. Furthermore, we describe a simplified culture protocol that allows fast expansion of virus-specific TSCM starting from a mixed naive T/TSCM pool of PBLs. Due to the clinical-grade compatibility, this might be the basis for novel cell therapeutic options in life-threatening courses of viral and tumor disease.


A Haptotaxis Assay for Leukocytes Based on Surface-Bound Chemokine Gradients NOVEL IMMUNOLOGICAL METHODS]

The migration of leukocytes in response to chemokine gradients is an important process in the homeostasis of the human immune system and inflammation. In vivo the migration takes place on the surface of the endothelium to which the chemokine gradient is immobilized via interaction with glycosaminoglycans. To study leukocyte migration in response to surface-bound chemokines, we generated chemokine gradients by a simple stamping method: agarose stamps were soaked with chemokine solution to form continuous chemokine gradients by diffusion. These gradients could be easily transferred to a petri dish surface by stamping. We show that neutrophil granulocytes recognize these gradients and migrate toward increasing chemokine concentrations dependent on the slope of the gradient. Single-cell responses were recorded, and statistical analyses of cell behavior and migration were performed. For analysis of chemotaxis/haptotaxis, we propose a chemotactic precision index that is broadly applicable, valid, and allows for a straightforward and rapid quantification of the precision by which cells follow the direction of a given gradient. The presented technique is very simple, cost-efficient, and can be broadly applied for generating defined and reproducible immobilized gradients of almost any protein on surfaces, and it is a valuable tool to study haptotaxis.


Correction Vector-Encoded Helicobacter Pylori Neutrophil-Activating Protein Promotes Maturation of Dendritic Cells with Th1 Polarization and Improved Migration CORRECTIONS]

Correction: Vector-Encoded Helicobacter Pylori Neutrophil-Activating Protein Promotes Maturation of Dendritic Cells with Th1 Polarization and Improved Migration [CORRECTIONS]

Pulmonary Alveolar Macrophages Contribute to the Premetastatic Niche by Suppressing Antitumor T Cell Responses in the Lungs TUMOR IMMUNOLOGY]

In contrast to tumor-associated macrophages, myeloid-derived suppressor cells, or inflammatory monocytes, functions of tissue resident macrophages, including alveolar macrophages (AM), in cancer were not well studied. Using a mouse model of breast cancer, we show that AM promote cancer metastasis to the lungs by suppressing antitumor T cells in this organ. AM accumulated in the premetastatic lungs through complement C5a receptor–mediated proliferation but not through recruitment from the circulation. AM preconditioned by breast tumors inhibited Th1 and favored generation of Th2 cells that had lower tumoricidal activity than Th1 cells. In addition, AM reduced the number and maturation of lung dendritic cells by regulating TGF-β in the lung environment. Depletion of AM reversed immunosuppression imposed by these cells and strengthened local Th1 responses, which significantly reduced lung metastatic burden. C5a receptor deficiency, which also lessens myeloid-derived suppressor cells in the premetastatic niche, synergized with the depletion of AM in preventing metastasis, leading to protection of mice from lung metastases. This study identifies AM as a new component of the premetastatic niche, which is harnessed by tumors to impose immunosuppression, and as a new target for cancer immunotherapies to eliminate or reduce metastasis. Because the lungs are the most common target for hematogenous metastasis, this research offers a plausible explanation for susceptibility of the lungs to cancer metastasis.


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