Migration of hematopoietic stem cells through the blood, across the endothelial vasculature to different organs and to their bone marrow (BM) niches, requires active navigation, a process termed homing. Homing is a rapid process and is the first and essential step in clinical stem cell transplantation. Similarly, homing is required for seeding of the fetal BM by hematopoietic progenitors during...

Memory CD4 T cells express characteristic adhesion molecules and chemokine receptors that dictate their recirculation to the tissue in which they first encountered antigen. On page 1045, Baekkevold and colleagues show that T cells may compete for access to the skin and only gain entry if they express the CC-chemokine receptor-4 (CCR4). Previous studies showed that skin-homing and gut-homing CD4...

Tumor cell surface aminopeptidase N (APN or CD13) has two puzzling functions unrelated to its enzymatic activity: mediating tumor cell motility and serving as a receptor for tumor-homing peptides (peptides that bring anti-cancer drugs to tumor cells). To investigate APN-based tumor-homing therapy, we determined the crystal structure of APN complexed with a tumor-homing peptide containing a repr...

The transcription factor T-bet was identified in CD4(+) T cells, and it controls interferon gamma production and T helper type 1 cell differentiation. T-bet is expressed in certain other leukocytes, and we recently showed (Lord, G.M., R.M. Rao, H. Choe, B.M. Sullivan, A.H. Lichtman, F.W. Luscinskas, and L.H. Glimcher. 2005. Blood. 106:3432-3439) that it regulates T cell trafficking. We examined...

Homing of the phage T4 td intron is initiated by the intron-encoded endonuclease I-TevI, which cleaves the intronless allele 23 and 25 nucleotides upstream of the intron insertion site (IS). The distance between the I-TevI cleavage site (CS) and IS implicates endo- and/or exonuclease activities to resect the DNA segment between the IS and CS. Furthermore, 3' tails must presumably be generated f...

Tissue-specific homing of effector and memory T cells to skin and small intestine requires the imprinting of specific combinations of adhesion molecules and chemokine receptors by dendritic cells in the draining lymph nodes. In this study, we demonstrate that CD8(+) T cells activated by Ag-pulsed bone marrow-derived dendritic cells were induced to express the small intestine homing receptors al...

The α-chemokine stromal-derived factor 1 (SDF-1), which binds to the CXCR4 receptor, directs migration and homing of CXCR4+ hematopoietic stem/progenitor cells (HSPCs) to bone marrow (BM) stem cell niches. Nevertheless, it is also known that CXCR4-/- fetal liver-derived hematopoietic stem cells engraft into BM and that blockade of CXCR4 by its antagonist AMD3100 does not prevent engraftment of ...

FTY720 is a sphingosine-derived immunosuppressant. Phosphorylated FTY720 promotes T cell homing from spleen and peripheral blood to LNs by acting as an agonist for sphingosine-1-phosphate (S1P) receptors. Here we demonstrate that FTY720 enhances the activity of the sphingosine transporter Abcb1 (Mdr1) and the leukotriene C(4) transporter Abcc1 (Mrp1). Both transporters must be active for FTY720...

To discover small molecules that modulate hematopoietic cell homing after adoptive transfer, we created a transgenic zebrafish expressing firefly luciferase downstream of the ubiquitin promoter (ubi:luc) to serve as a hematopoietic donor. Bioluminescence imaging (BLI) was used to detect and follow ubi:luc hematopoietic cells that homed to the marrow as early as 1 day post-transplant. BLI was ab...

Mobile operators currently prefer optimizing their radio networks via re-homing or cutting over the cell sites in 2G or 3G networks. The core network, as the parental part of radio network, is inevitably impacted by the re-homing in radio domain. This paper introduces the cell site re-homing in radio network and analyzes its impact on the performance of GSM/UMTS core network. The possible re-ho...