BACKGROUND We have investigated the usefulness of a model of cardiac development in a large mammal, sheep, for studies of engraftment of human stem cells in the heart. METHODS AND RESULTS Adult and fetal human mesenchymal stem cells were injected intraperitoneally into sheep fetuses in utero. Hearts at late fetal development were analyzed for engraftment of human cells. The majority of the en...

We have established fetal liver-derived T cell receptor (TCR) gamma/delta+, CD3+ T cell lines that are cytotoxic for maternal T cells. Fetal liver-derived lymphoid progenitors yielded predominantly TCR-gamma/delta+ cell clusters when cultured on fetal bone marrow-derived stromal cells in the presence of a cytokine cocktail under magnetic force. These tightly adherent clusters were cloned by lim...

We have established fetal liver-derived T cell receptor (TCR)T/t~ + , CD3 + T cell lines that are cytotoxic for maternal T cells. Fetal liver-derived lymphoid progenitors yielded predominantly TCR-'y//~ + cell clusters when cultured on fetal bone marrow-derived stromal cells in the presence of a cytokine cocktail under magnetic force. These tightly adherent dusters were cloned by limiting dilut...

The ability to isolate fetal nucleated red blood cells (NRBCs) from the maternal circulation makes possible prenatal genetic analysis without the need for diagnostic procedures that are invasive for the fetus. Such isolation requires antibodies specific to fetal NRBCs. To generate a panel of antibodies to antigens present on fetal NRBCs, a new type of nonimmune phage antibody library was genera...

Despite advances in ex vivo expansion of cord blood-derived hematopoietic stem/progenitor cells (CB-HSPC), challenges still remain regarding the ability to obtain, from a single unit, sufficient numbers of cells to treat an adolescent or adult patient. We and others have shown that CB-HSPC can be expanded ex vivo in two-dimensional (2D) cultures, but the absolute percentage of the more primitiv...

The pre-B cell receptor (preBCR) plays critical roles in early B cell differentiation. It has been shown that not all muH chains are capable of pairing with surrogate light (SL) chains to form preBCR. Here, we established a novel system to differentially identify two types of early pre-B cell populations in bone marrow and fetal liver of mice, one producing SL-pairing muH chains and the other p...

We investigated roles of alpha4 integrins during hematopoiesis using mutant and chimeric mice. Yolk sac erythropoiesis and migration of hematopoietic progenitors to fetal liver, spleen, and bone marrow can occur without alpha4 integrins. Although terminal differentiation of these progenitors is possible without alpha4 integrins, these receptors are essential to maintain normal hematopoiesis in ...

To further investigate the erythroid nature of the two human erythroleukemia cell lines, K562 and HEL-60, and to define the ontogeny of pyruvate kinase (PK) isozymes (R, M2) in developing human erythroid cells, we have studied the isozymic alterations, if any, during differentiation of these cell lines in vitro and normoblasts isolated from fetal liver in vivo. PK activity of erythroleukemic ce...