miR-181a modulates acute myeloid leukemia susceptibility to natural killer cells.

Although daunorubicin (DNR) is the most widely used anthracycline to treat acute myeloid leukemia (AML), resistance to this drug remains a critical problem. The aim of this study was to investigate the relationship between AML resistance to daunorubicin and susceptibility to natural killer (NK) cell-mediated cell lysis, and the putative expression of miRs. For this purpose, we used the parental AML cell lines U-937 and KG-1 and their equivalent resistant U937(R) and KG-1(R) cell lines.

Autonomous phagosomal degradation and antigen presentation in dendritic cells.

Phagocytosis plays a critical role in both innate and adaptive immunity. Phagosomal fusion with late endosomes and lysosomes enhances proteolysis, causing degradation of the phagocytic content. Increased degradation participates in both innate protection against pathogens and the production of antigenic peptides for presentation to T lymphocytes during adaptive immune responses.

Sec22b regulates phagosomal maturation and antigen crosspresentation by dendritic cells.

Antigen (Ag) crosspresentation by dendritic cells (DCs) involves the presentation of internalized Ags on MHC class I molecules to initiate CD8+ T cell-mediated immunity in response to certain pathogens and tumor cells. Here, we identify the SNARE Sec22b as a specific regulator of Ag crosspresentation. Sec22b localizes to the ER-Golgi intermediate compartment (ERGIC) and pairs to the plasma membrane SNARE syntaxin 4, which is present in phagosomes (Phgs).

Activation of cytotoxic T-cell receptor gammadelta T lymphocytes in response to specific stimulation in myelodysplastic syndromes.

Background: We previously reported that the function and proliferation of natural killer cells in myelodysplastic syndromes are defective. T-cell receptor gammadelta T cells are other important components of innate immunity that have been recently implicated in the immune response against hematologic malignancies.

Design And Methods: We evaluated the phenotype, function, and in vitro expansion of myelodysplastic syndrome patient-derived gammadelta T cells in response to interleukin-2 and bromohalohydrin pyrophosphate, a synthetic phosphoantigen with a potent T-cell receptor gammadelta agonist effect that specifically activates and amplifies this T-cell population.

The HOXB4 homeoprotein differentially promotes ex vivo expansion of early human lymphoid progenitors.

The HOXB4 homeoprotein is known to promote the expansion of mouse and human hematopoietic stem cells (HSCs) and progenitors of the myeloid lineages. However, the putative involvement of HOXB4 in lymphopoiesis and particularly in the expansion of early lymphoid progenitor cells has remained elusive. Based on the ability of the HOXB4 protein to passively enter hematopoietic cells, our group previously designed a long-term culture procedure of human HSCs that allows ex vivo expansion of these cells.