Relevance of CD6-Mediated Interactions in the Regulation of Peripheral T-Cell Responses and Tolerance.

The CD6 lymphocyte receptor has been involved in the pathophysiology of different autoimmune disorders and is now considered a feasible target for their treatment. data show the relevance of CD6 in the stabilization of adhesive contacts between T-cell and antigen-presenting cells, and the modulation of T-cell receptor signals. However, the consequences of such a function are yet undisclosed due to the lack of suitable genetically modified animal models.

Ly9 (CD229) Cell-Surface Receptor is Crucial for the Development of Spontaneous Autoantibody Production to Nuclear Antigens.

The Signaling Lymphocyte Activation Molecule Family (SLAMF) genes, which encode cell-surface receptors that modulate innate and adaptive immune responses, lay within a genomic region of human and mouse chromosome 1 that confers a predisposition for the development of systemic lupus erythematosus (SLE). Herein, we demonstrate that the SLAMF member Ly9 arises as a novel receptor contributing to the reinforcement of tolerance. Specifically, Ly9-deficient mice spontaneously developed features of systemic autoimmunity such as the production of anti-nuclear antibodies (ANA), -dsDNA, and -nucleosome autoantibodies, independently of genetic background [(B6.

Expression profiles of novel cell surface molecules on B-cell subsets and plasma cells as analyzed by flow cytometry.

Cell surface molecules are present on several lymphocyte subsets and are differentially expressed during lymphocyte development and activation. Human Leukocyte Differentiation Antigen (HLDA) Workshops have played an essential role in the identification and characterization of the molecules found in the membrane of hematopoietic cells. In the present study, the reactivities of sixty-five monoclonal antibodies (mAbs) submitted to the HLDA9 Workshop were tested.

Expression of SLAM (CD150) cell-surface receptors on human B-cell subsets: from pro-B to plasma cells.

The SLAM (CD150) family receptors are leukocyte cell-surface glycoproteins involved in leukocyte activation. These molecules and their adaptor protein SAP contribute to the effective germinal center formation, generation of high-affinity antibody-secreting plasma cells, and memory B cells, thereby facilitating long-term humoral immune response. Multi-color flow cytometric analysis was performed to determine the expression of CD48 (SLAMF2), CD84 (SLAMF5), CD150 (SLAM or SLAMF1), CD229 (Ly9 or SLAMF3), CD244 (2B4 or SLAMF4), CD319 (CRACC, CS1, or SLAMF7), and CD352 (NTB-A or SLAMF6) on human cell lines and B-cell subsets.

New B-cell CD molecules.

B cells not only play a pivotal role in humoral immunity, but also are involved in a broad spectrum of immune responses, including antigen presentation and T-cell function regulation. The identification of cell-surface CD molecules derived from a series of Human Leukocyte Differentiation Antigens (HLDA) Workshops has been instrumental to the discovery and functional characterization of human B-cell populations. Moreover, many events regulating B-cell development, activation, and effector functions are orchestrated by these cell-surface molecules.

Mouse CD84 is a pan-leukocyte cell-surface molecule that modulates LPS-induced cytokine secretion by macrophages.

CD84 is 1 of the 9 SLAM family cell-surface receptors involved in leukocyte activation. The CD84 ectodomain is highly glycosylated, and its cytoplasmic tail contains 2 copies of an ITSM, which can be phosphorylated. Here, we report that although mouse CD84 was present on all BM HSCs, its expression declined in developing thymic and BM lymphocytes.

Human lung mast cells mediate pneumococcal cell death in response to activation by pneumolysin.

Mast cells are emerging as contributors to innate immunity. Mouse mast cells have a pivotal role in protection against bacterial infection, and human cord blood-derived mast cells reduce bacterial viability in culture. The objectives of this study were to determine whether human lung mast cells (HLMCs) might be protective against pneumococcal lung infection through direct antimicrobial activity.