Involvement of insulin-like growth factor-I and insulin-like growth factor binding proteins in pro-B-cell development.

Objective: Insulin-like growth factor (IGF)-binding proteins (IGFBPs) are a family of proteins thought to modulate IGF function. By employing an in vitro culture system of human hematopoietic stem cells cocultured with murine bone marrow stromal cells, we examined the effects of IGF-I and IGFBPs on early B-cell development.

Materials And Methods: Human CD34(+) bone marrow cells were cocultured with murine stromal MS-5 cells for 4 weeks, and pro-B-cell number was analyzed by flow cytometry.

Porcine TCR CD3zeta-chain and eta-chain.

Complete porcine CD3zeta-chain cDNA sequence was obtained for the first time, and its genomic nucleotide sequence was investigated from exon 2 down to CD3eta-chain exon 8. The sequence of porcine CD3zeta-chain showed homologous amino acid sequence with human and murine counterparts, in contrast to CD3eta-chain exon 8 with diversity among animals previously investigated. CD3eta-chain peptide is an alternative splice form of CD3zeta-chain exon 7 splicing to CD3eta-chain exon 8 instead of CD3zeta-chain exon 8.

Dietary bioflavonoids induce apoptosis in human leukemia cells.

Dietary bioflavonoids are secondary metabolites of plants that are known to have a variety of bio-effects, including anti-cancer activity. In this study, we examined the effects of flavonoids on the growth of human leukemia cells and found that certain flavonoids induce apoptosis in a variety of human leukemia cells. The apoptosis induced by bioflavonoids was dose-dependent and was accompanied by a disruption of the mitochondrial transmembrane potential and the activation of caspase.

Development of novel monoclonal antibody 4G8 against swine leukocyte antigen class I alpha chain.

A mouse monoclonal antibody (MAb) was generated against swine leukocyte antigen (SLA) class I alpha chain. A newly developed series of MAb clones that react with pan leukocytes were selected and tested by immuno-histochemistry using SLA class I alpha chain expressing Cos-7 cells. Among them, MAb 4G8 was characterized by the following features: (1) 4G8 reacted with Cos-7 cells transfected with SLA class I alpha chain from the d haplotype, (2) 4G8 recognized epitopes that were different from those of commercially available anti-SLA class I MAbs 74-11-10 and PT85A, and (3) 4G8 could be used to immunostain frozen sections of thymus, spleen, lymph node, kidney, and liver tissues with good results.

Deficiency of BLNK hampers PLC-gamma2 phosphorylation and Ca2+ influx induced by the pre-B-cell receptor in human pre-B cells.

B-cell linker protein (BLNK) is a component of the B-cell receptor (BCR) as well as of the pre-BCR signalling pathway, and BLNK(-/-) mice have a block in B lymphopoiesis at the pro-B/pre-B cell stage. A recent report described the complete loss or drastic reduction of BLNK expression in approximately 50% of human childhood pre-B acute lymphoblastic leukaemias (ALL), therefore we investigated BLNK expression in human pre-B ALL cell lines. One of the four cell lines tested, HPB-NULL cells, was found to lack BLNK expression, and we used these human pre-B ALL cell lines that express and do not express BLNK to investigate the intracellular signalling events following pre-BCR cross-linking.

Characterization of a shiga-toxin 1-resistant stock of vero cells.

Shiga toxins (Stxs, also referred to as verotoxins) were first described as a novel cytotoxic activity against Vero cells. In this study, we report the characterization of an Stx1-resistant (R-) stock of Vero cells. (1) When the susceptibility of R-Vero cells to Stx1 cytotoxicity was compared to that of Stx1-sensitive (S-) Vero cells by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, cell viability after 48-hr exposure to 10 pg/ml of Stx1 was greater than 80% and less than 15%, respectively.

Diagnostic importance of CD179a/b as markers of precursor B-cell lymphoblastic lymphoma.

Surrogate light chains consisting of VpreB (CD179a) and lambda5 (CD179b) are expressed in precursor B cells lacking a complete form of immunoglobulin and are thought to act as substitutes for conventional light chains. Upon differentiation to immature and mature B cells, CD179a/b disappear and are replaced with conventional light chains. Thus, these molecules may be useful as essential markers of precursor B cells.

Cloning and characterization of porcine common gamma chain gene.

The common gamma chain, which was originally identified as a component of interleukin-2 receptors (IL-2R), plays a key role in differentiation of T lymphocytes and natural killer (NK) cells. In the present study, cDNA of the porcine common gamma chain gene and its genomic DNA were molecularly cloned and characterized. The porcine common gamma chain gene was found to consist of 8 exons, spanning approximately 3.

Raft.1, a monoclonal antibody raised against the raft microdomain, recognizes G-protein beta1 and 2, which assemble near nucleus after shiga toxin binding to human renal cell line.

Raft microdomains are glycolipid-enriched microdomain scaffolding molecules involved in signal transduction. The binding of Shiga toxin to globotriaosyl ceramide in raft microdomains of the human renal tubular cell line ACHN causes temporal activation of Src-kinase Yes. To study the downstream signaling mechanism proceeding to the activation of Yes, we raised monoclonal antibodies (MAbs) against raft microdomains.

Rum1, an inhibitor of cyclin-dependent kinase in fission yeast, is negatively regulated by mitogen-activated protein kinase-mediated phosphorylation at Ser and Thr residues.

The p25(rum1) is an inhibitor of Cdc2 kinase expressed in fission yeast and plays an important role in cell-cycle control. As its amino-acid sequence suggests that p25(rum1) has putative phosphorylation sites for mitogen-activated protein kinase (MAPK), we investigated the ability of MAPK to phosphorylate p25(rum1). Direct in vitro kinase assay using GST-fusion proteins of wild-type as well as various mutants of p25(rum1) demonstrated that MAPK phosphorylates the N-terminal portion of p25(rum1) and residues Thr13 and Ser19 are major phosphorylation sites for MAPK.