Isolation of an adult blood-derived progenitor cell population capable of differentiation into angiogenic, myocardial and neural lineages.

Blood-derived adult stem cells were previously considered impractical for therapeutic use because of their small numbers. This report describes the isolation of a novel human cell population derived from the peripheral blood, termed synergetic cell population (SCP), and defined by the expression of CD31Bright, CD34+, CD45-/Dim and CD34Bright, but not lineage-specific features. The SCP was capable of differentiating into a variety of cell lineages upon exposure to defined culture conditions. The resulting cells exhibited morphological, immunocytochemical and functional characteristics of angiogenic, neural or myocardial lineages. Angiogenic cell precursors (ACPs) expressed CD34, CD133, KDR, Tie-2, CD144, von Willebrand factor, CD31Bright, concomitant binding of Ulex-Lectin and uptake of acetylated low density lipoprotein (Ac-LDL), secreted interleukin-8, vascular endothelial growth factor and angiogenin and formed tube-like structures in vitro. The majority of CD31Bright ACP cells demonstrated Ac-LDL uptake. Neural cell precursors (NCPs) expressed the neuronal markers Nestin, betaIII-Tubulin, and Neu-N, the glial markers GFAP and O4, and responded to neurotransmitter stimulation. Myocardial cell precursors (MCPs) expressed Desmin, cardiac Troponin and Connexin 43. In conclusion, the simple and rapid method of SCP generation and the resulting considerable quantities of lineage-specific precursor cells makes it a potential source of autologous treatment for a variety of diseases.

Killer cell Ig-like receptor and leukocyte Ig-like receptor transgenic mice exhibit tissue- and cell-specific transgene expression.

To generate an experimental model for exploring the function, expression pattern, and developmental regulation of human Ig-like activating and inhibitory receptors, we have generated transgenic mice using two human genomic clones: 52N12 (a 150-Kb clone encompassing the leukocyte Ig-like receptor (LILR)B1 (ILT2), LILRB4 (ILT3), and LILRA1 (LIR6) genes) and 1060P11 (a 160-Kb clone that contains ten killer cell Ig-like receptor (KIR) genes). Both the KIR and LILR families are encoded within the leukocyte receptor complex, and are involved in immune modulation. We have also produced a novel mAb to LILRA1 to facilitate expression studies. The LILR transgenes were expressed in a similar, but not identical, pattern to that observed in humans: LILRB1 was expressed in B cells, most NK cells, and a small number of T cells; LILRB4 was expressed in a B cell subset; and LILRA1 was found on a ring of cells surrounding B cell areas on spleen sections, consistent with other data showing monocyte/macrophage expression. KIR transgenic mice showed KIR2DL2 expression on a subset of NK cells and T cells, similar to the pattern seen in humans, and expression of KIR2DL4, KIR3DS1, and KIR2DL5 by splenic NK cells. These observations indicate that linked regulatory elements within the genomic clones are sufficient to allow appropriate expression of KIRs in mice, and illustrate that the presence of the natural ligands for these receptors, in the form of human MHC class I proteins, is not necessary for the expression of the KIRs observed in these mice.