The proposed algorithm is compatible with the link-adaptation mechanisms implemented in commercial WLANs, as it limits the amount of time during which the stations control the wireless medium.

Transferrin (Trf) is a highly conserved serum glycoprotein mostly known for its iron transport capacity. As iron is an indispensable nutrient for cell division, Trf and its receptor have long been used as targets of pharmacological intervention mostly for cancer therapy and for diagnosis in inflammation. In recent years several independent pieces of work including data from our group, indicated that Trf can also have an iron independent role in the immune system. In this article new emerging roles of Trf and its receptor on iron independent processes and in drug delivery are reviewed.

SUMMARYTransferrin, the major plasma iron carrier, mediates iron entry into cells through interaction with its receptor. Several in vitro studies have demonstrated that transferrin plays an essential role in lymphocyte division, a role attributed to its iron transport function. In the present study we used hypotransferrinaemic (Trf hpx ⁄ hpx ) mice to investigate the possible involvement of transferrin in T lymphocyte differentiation in vivo. The absolute number of thymocytes was substantially reduced in Trf hpx ⁄ hpx mice, a result that could not be attributed to increased apoptosis. Moreover, the proportions of the four major thymic subpopulations were maintained and the percentage of dividing cells was not reduced. A leaky block in the differentiation of-(TN4) cells was observed. In addition, a similar impairment of early thymocyte differentiation was observed in mice with reduced levels of transferrin receptor. The present study demonstrates, for the first time, that transferrin itself or a pathway triggered by the interaction of transferrin with its receptor is essential for normal early T-cell differentiation in vivo.

Thymus Recipients Ja18-/-Ja18-/-Spleen Recipients Ja18-/-Ja18-/

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SummaryLow CD8 + T lymphocyte numbers have long been described in hereditary haemochromatosis (HH). Recently, two conserved haplotypes localized near the microsatellite D6S105 at the major histocompatibility complex (MHC) class I region were described predicting the clinical expression of HH and the CD8 + T lymphocyte numbers. The A-A-T haplotype was associated with a severe clinical expression of HH and low CD8 + T lymphocyte numbers, while the G-G-G haplotype was associated with a milder clinical expression of HH and high CD8 + T lymphocyte numbers. As CD8 + T lymphocytes are a very heterogeneous population, in this study we analysed the CD8 + subpopulations of naive, central memory (TCM) and effector memory (TEM), and further subsets of CD8 + TEM cells in 47 HH patients and 68 controls. In addition, association studies were conducted between the conserved haplotypes and the CD8 + T cell subpopulations in HH. Variations of the numbers of naive and central memory cells with age were similar between HH patients and controls. For TEM cells and the TEM CD27 -CD28 -subset no effect of age was observed in HH [R 2 = 0·001, not significant (n.s.) and R 2 = 0·01, n.s., respectively] contrasting with the increasing of these subpopulations with age in controls (R 2 = 0·09, P = 0·017 and R 2 = 0·22, P = 0·0005, respectively). Interestingly, patients homozygous for the A-A-T haplotype have lower numbers of CD8 + TEM cells due especially to lower numbers of TEM CD27 -CD28 -(0·206 Ϯ 0·119 and 0·066 Ϯ 0·067 ¥ 10 6 cells/ml, respectively) than patients carrying the G-G-G haplotype (0·358 Ϯ 0·195 and 0·246 Ϯ 0·202 ¥ 10 6 cells/ml, respectively). This may suggest an inability of HH patients to differentiate the CD8 + T cells into the most mature phenotype.

Lipid-specific T cells comprise a group of T cells that recognize lipids bound to the MHC class I-like CD1 molecules. There are four isoforms of CD1 that are expressed at the surface of antigen presenting cells and therefore capable of presenting lipid antigens: CD1a, CD1b, CD1c, and CD1d. Each one of these isoforms has distinct structural features and cellular localizations, which promotes binding to a broad range of different types of lipids. Lipid antigens originate from either self-tissues or foreign sources, such as bacteria, fungus, or plants and their recognition by CD1-restricted T cells has important implications in infection but also in cancer and autoimmunity. In this review, we describe the characteristics of CD1 molecules and CD1-restricted lipid-specific T cells, highlighting the innate-like and adaptive-like features of different CD1-restricted T cell subtypes.

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