Human pre-B Cell Line Research Articles

The immunoglobulin λ-like gene cluster (14.1, 16.1, and Fλ1) contains gene(s) selectively expressed in pre-B cells and is the human counterpart of the mouse λ5 gene

A human immunoglobulin (Ig)-related gene, covering approximately 8 kb, was isolated from a cosmid genomic library, by hybridization with a C lambda probe and with a lambda-like probe. This gene was identified as 14.1 It belongs to the human lambda-like cluster which is composed of three genes (14.1, 16.1 and F lambda 1) that do not rearrange. Sequence data indicate that 14.1 is organized similarly to the mouse lambda 5 gene. It contains three exons with lengths of 69, 38, and 106 codons as compared with 65, 38, and 106 for exons 1, 2, and 3 of mouse lambda 5, respectively. The corresponding homology values were 61, 66 and 75.5%. Using a 14.1 specific probe containing exon 1, we showed that this gene was selectively expressed in human pre-B cell lines. It is likely to encode a 213-amino acid lambda-like light chain that would associate with mu chains and play an important role in the early steps of B cell differentiation.

Phorbol myristate acetate induces both high affinity and low affinity interleukin 2-receptors on a pre-B leukemic cell line

The human pre-B leukemic cell line Reh6 does not constitutively express the Tac molecule (p55), which is one of the two polypeptide chains of the interleukin 2-receptor (IL2-R). Cell incubation with Phorbol Myristate Acetate (PMA) induces expression of the Tac molecule in a dose and time-dependent manner. Binding experiments with radiolabelled recombinant IL2 (rIL2) revealed both high and low affinity IL2-R (225 ± 105 sites/cell with a K d of 130 ± 51 pM and 24060 sites/cell with a K d of 17.3 nM respectively), whereas unstimulated Reh6 cells only expressed intermediate affinity IL2-R (58 sites per cell with a K d of 460 pM). Cross-linking of radiolabelled rIL2 to PMA-incubated Reh6 cells revealed the presence of two polypeptide chains of mol. wts 55,000 (Tac molecule) and 70,000, as in normal activated T cells, while the 70,000 mol. wt chain alone was observed in unstimulated Reh6 cells. IL2-R-bearing Reh6 cells could absorb rIL2 in a dose-dependent manner and this absorption was inhibited by a monoclonal antibody against the Tac molecule (anti-Tac). Moreover, partial internalization of IL2 bound under high affinity conditions occurred at 37°C. IL2-R expressed on PMA-induced cells were functional since rIL2 specifically enhanced the proliferation in vitro of PMA-treated cells in semi-solid but not liquid cultures. These findings thus demonstrate an IL2-dependent mechanism of proliferation in vitro of pre-B leukemic cells induced by PMA, which can express high affinity, functional IL2-R.

Identification of high affinity receptors for vasoactive intestinal peptide on human lymphocytes of B cell lineage.

Specific, high affinity receptors for vasoactive intestinal peptide (VIP) have been identified on a human pre-B cell line, Nalm 6, and on a human plasma cell line, Dakiki. The single class of high affinity sites exhibited a KD of 12.6 +/- 2.9 nM for VIP in Nalm 6 cells and 9.1 +/- 2.7 nM in Dakiki plasma cells. The homologous peptides, peptide histidine methionine (PHM), growth hormone releasing factor (GHRF), and secretin were all less effective than VIP in competitively inhibiting binding of 125I-VIP to Nalm 6 and Dakiki plasma membranes. The putative receptor was characterized as a 47-kDa protein using covalent cross-linking techniques and VIP stimulated adenylate cyclase in pre-B cells. Human lymphocytes of B cell lineage thus appear to express functional VIP receptors homologous to the receptor identified in T lymphoblasts, brain, pituitary, and intestine.

Insulin receptor overexpression in a human pre-B acute lymphocytic leukemia cell line with a t(1;19) chromosome translocation near the INSR locus

Human pre-B acute lymphocytic leukemia (ALL) cell line 697 contains a disease-specific chromosomal translocation, t(1;19), near the insulin receptor locus (INSR). Insulin binding, insulin receptor kinase and cell surface immunofluorescence experiments all show that 697 cells express more surface insulin receptors than 207 cells, a line of pre-B ALL cells that lack the t(1;19). Northern blot analysis confirms that 697 cells have increased levels of mRNA for the insulin receptor. Gene dosage and in situ hybridization analysis indicate that only two copies of the INSR locus are present in 697 cells, one on the translocation chromosome and one on the normal chromosome 19. The results described here demonstrate that transcriptional up-regulation of the INSR locus is correlated with the t(1;19) translocation found in human pre-B ALL cell line 697.

Mu heavy chains can associate with a pseudo-light chain complex (ψL) in human pre-B cell lines

In pre-B cells, the earliest identifiable stage of B cell differentiation, there is an asynchrony of immunoglobulin chain expression in that mu heavy chains are synthesized in the absence of light chain synthesis. These mu chains largely remain intracellular and are degraded. Here we demonstrate that a fraction of mu chains in human pre-B cell lines can reach the surface in association with three pre-B-specific proteins with relative molecular masses of 22, 18, and 16 kd, which we term collectively the pseudo-light chain complex, psi L. This association generates a multimeric complex, mu 2-psi L. Two of the psi L proteins (22 and 16 kd) are lambda-immunoreactive and form disulfide bonds with mu chains, suggesting that they are closely related to conventional lambda light chains. The 18 kd psi L species is a non-covalently-associated member of the complex. The expression of mu-psi L complexes on the surface of pre-B cells could have a functional role in the control of pre-B growth and differentiation by the hematopoietic microenvironment.

Identification of a human endothelial cell antigen with monoclonal antibody 44G4 produced against a pre-B leukemic cell line.

Staining of a variety of human tissue sections (lymph node, tonsil, spleen, thymus, kidney, lung, and liver) by the indirect immunoperoxidase method indicated that mAb 44G4, produced against a human pre-B leukemic cell line, was strongly reactive with vascular endothelium. All other cell types observed in these tissues were unreactive. Immunofluorescence staining of endothelial cells isolated from umbilical cord vein and grown in culture confirmed that mAb 44G4 recognized a surface membrane component of vascular endothelium. Granulocytes, monocytes, B and T lymphocytes, and T lymphocytes cultured in the presence of PHA for 72 h did not express the 44G4 Ag. mAb 44G4 reacted weakly with leukemic cells from 28 of 41 patients with non-T cell acute lymphocytic leukemia and 4 of 7 patients with acute myelocytic leukemia, whereas 8 of 10 cases of T cell acute lymphocytic leukemia were negative. Moderate reactivity with leukemic cell lines of pre-B and myelomonocytic origin was also observed. The level of 44G4 Ag on umbilical endothelial cells was three to five times that of leukemic cell lines and 25 times the average levels observed on leukemic cells isolated from patients. Immunoprecipitation of lysates prepared from surface-iodinated endothelial cells and the immunizing pre-B leukemic cell line revealed that the 44G4 Ag from both cell types was composed of two subunits of apparent m.w. 95,000 linked by disulfide bond(s). Comparison of the cellular localization and subunit structure of 44G4 to that of known Ag suggests that it represents a previously undescribed marker of endothelial cells.

Structure and pre-B lymphocyte restricted expression of the VpreB in humans and conservation of its structure in other mammalian species.

DNA from several mammals, including humans, was found to contain one or more restriction enzyme digested DNA fragments which hybridized to the mouse VpreB gene under stringencies demonstrating at least 70% nucleotide sequence homologies, indicating that the VpreB locus may be widespread and highly conserved among mammals. A human VpreB genomic clone was isolated and sequenced. Two exons and the intervening intron are spaced almost identically as in the mouse VpreB1 gene, and show 76% sequence homology to the mouse gene. As in the mouse VpreB1 gene, the 5' end of the human VpreB gene contains characteristic features of Ig domains, while the 3' end is Ig non-related. This 3' Ig non-related structure of the VpreB gene(s) may, therefore, have existed before the speciation of humans and mice over 65 million years ago. Sequences encoding the entire putative second framework region and a stretch in the third framework region are identical in human and mouse VpreB. the human VpreB gene appears to be selectively expressed in human pre-B cell lines as an 0.85 kb poly(A)+ RNA. Its expression promises to be a useful marker for the detection of normal and malignant human pre-B lymphocytes.

Le C3 stimule la prolifération des cellules humaines pré-B de la lignée Raji

In a defined medium in which transferrin (3 micrograms/ml) was the only source of exogenous proteins, Raji cells of the human pre-B lymphoblastoid cell line died within 48 h after forming polykaryons. The simple addition of purified C3 at a concentration equal to or higher than 3 micrograms/ml allowed Raji cells to divide. This preliminary report provides a defined system for studying the mitogenic effect of human C3 or C3 fragments upon proliferation of human B-cells lines.

Induction of HLA-DC/DS (LEU 10) antigen expression by human precursor B cell lines.

The expression of HLA-DC/DS antigen detected by the monoclonal antibody Leu 10 was studied in three human precursor and pre-B cell lines (Josh 7, Reh, and Nalm 12). Flow cytometric analysis showed that none of these cell lines stained for the HLA-DC/DS antigen. In the presence of 1.6 X 10(-9) M of 12-O-tetradecanoylporbol-13-acetate (TPA), expression of this antigen was detected. The expression was completed after 168 h of incubation. Iodination of cell surface, immunoprecipitation by Leu 10 antibody, and two-dimensional gel analysis revealed that TPA-treated Josh 7 cells synthesized and expressed a 29,34 kD bimolecular complex with both alpha and beta chains different from those of HLA-DR antigen. Quantitative absorption experiments with cell lysates indicated a greater than 25-fold increase in HLA-DC/DS antigen in TPA-treated cells. With the induction of HLA-DC/DS antigen expression, there are concomitant decreases in the expression of the common acute lymphoblastic leukemia antigen (CALLA) and the enzymatic activity of terminal deoxynucleotidyl transferase. No appreciable changes in HLA-DR and Ig expression were observed. There was also no change in HLA-SB expression as detected by antibody ILR-1. However, DNA synthesis was markedly inhibited by TPA treatment. These results indicate that precursor and pre-B cell lines can be induced to mature in vitro. They also suggest that the expression of HLA-DC/DS antigen which precedes the expression of membrane Ig and follows the HLA-DR expression is relevant to human B cell development and cell interaction.

Ig biosynthesis in a human pre-B cell line.

Ig synthesis was investigated in a human Epstein-barr virus transformed pre-B-like lymphoblastoid line, Josh 4. Translation of total extracted cellular RNA in a wheat germ cellfree system showed that the transcripts for both micrometer (the heavy chain of membrane IgM) and micros (the heavy chain of secreted IgM) were present in approximately equal proportions. Pulse-labeling of cells with 35S-methionine in culture followed by immunoprecipitation and endo-N-acetylglucosaminidase digestion of the precipitates demonstrated that each of these chains were synthesized and glycosylated intracellularly. No light chain synthesis was detected in either system. In addition, both mu-chains were found to be secreted. Hybrids formed between Josh 4 and 2 light chain-producing lymphoblastoid lines, RPMI-8866P (IgG kappa) and 32a1 (IgA lambda), were found to express surface IgM. Thus the provision of light chains permitted membrane expression of chains which might otherwise be degraded. These findings were discussed in relation to normal B cell development.

Characterization of a novel human pre-B leukemia cell line.

The derivation of a new human pre-B cell line from the leukocytes of a girl in the leukemic phase of lymphoblastic lymphoma is reported. Cells of this line, termed SMS-SB, synthesized mu but not light chains. These mu-chains were found only in the cytoplasm and were not secreted. SMS-SB cells bore HLA-DR determinants. They did not express the common ALL antigen or terminal deoxynucleotidyl transferase and, therefore, differed from previously described human pre-B leukemia cell lines. SMS-SB cells resembled certain Abelson leukemia virus-transformed mouse bone marrow cells. Except for the lack of formed mouse bone marrow cells. Except for the lack of mu secretion, the phenotype of SMS-SB cells was the same as the major subpopulation of marrow pre-B cells.