Self-renewal, pluripotency, and long-term reconstitution are defining characteristics of single hematopoietic stem cells. Pax5(-/-) precursor B cells apparently possess similar characteristics. Here, using serial transplantations, with in vitro recloning and growth of the bone marrow-homed donor cells occurring after all transplantations, we analyzed the extent of self-renewal and hematopoietic...

In cowpea protoplasts infected with cowpea mosaic virus, a bottom-component (B) RNA-encoded 60-kilodalton (60K) polypeptide is synthesized, which is membrane-bound and represents the direct precursor to the genome-bound protein VPg. The relationship between this VPg precursor and other B-RNA-encoded polypeptides was studied. Digestion of the B-RNA-encoded 170K and 84K polypeptides with Staphylo...

The prognostic significance of chromosomal translocations, particularly t(l;19) (q23;p13), was evaluated in children with pre-B and early pre-B acute lymphoblastic leukemia (ALL). Patients were treated on a risk-based protocol of the Pediatric Oncology Group (POW between February 1986 and May 1989. An abnormal clone was detected in 46% (1 30 of 2851 of pre-B cases and 56% (380 of 679) of early ...

While chemically defined conditions for culturing normal tissue have been attained for only a few cell types, the sustained proliferation of B precursor cells expressing IL-7 receptor and c-Kit can be supported under chemically defined conditions containing recombinant IL-7 and the ligand for c-Kit (KL). To understand the biochemical basis of the cell cycle progression of B precursor cells prol...

BACKGROUND AND OBJECTIVE Normal B-cell differentiation has been characterized extensively, but discrepancies persist regarding the exact sequence of antigen expression. Few systematic studies focusing on identification of the minor or undetectable B-cell subsets in normal human bone marrow (BM) which are frequently found in leukemic cells have been performed. Such studies could help to monitor ...