Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activation of CD4+ T cells requires processing of exogenous protein antigens by antigen-presenting cells (APC). A macrophage hybridoma and B cell lymphoma were comparable in their ability to process hen egg lysozyme (HEL), which involves reduction of its disulfide bonds. The intracellular levels of cysteine and glutathione, major physiological thiols, based on protein content were similar within these cell lines. In addition, the cysteine transport pathway in viable cells was assessed by 35S-cystine uptake. For macrophages, the majority of the radioactivity resided in high density subcellular fractions of Percoll gradients that comigrated with lysosomal beta-galactosidase (beta-gal). Besides the lysosomes, low density fractions cosedimenting with endosomes incorporated the radiolabel in the B cells. Both peaks of radioactivity disappeared when the B cells were incubated with unlabeled carboxymethyl-cysteine (CM-cysteine), a specific competitor of the plasma membrane CG transport system. The distinct gradient profiles of radiolabel uptake in the cells correlated with a difference in their capacity to process the transferrin-lysozyme conjugate (TF-HEL). TF-HEL was significantly more stimulatory than HEL in inducing a HEL-specific T cell response with the B cells as the APC. However, the potencies of TF-HEL and HEL were similar when the macrophages were the APC. Thus, the intracellular location of cysteine transport activity may be cell lineage-dependent, and its presence may, in part, determine whether an organelle is a productive site of processing antigens with disulfide bonds that is necessary for CD4+ cell activation.
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PMID:Intracellular location of cysteine transport activity correlates with productive processing of antigen disulfide. 870 60

Plasmids carrying the Epstein-Barr virus (EBV) latent gene EBNA1 and the EBV latent origin of replication (oriP) stay in transfected human cells as autonomously replicating extrachromosomal genetic units. They thus might represent a suitable tool for cytokine gene introduction into human tumor cells with the prospect of therapeutic antitumor vaccination. The aim of this study was to analyze whether such plasmids permit stable and efficient expression of cytokine genes in human non-Hodgkin lymphoma cells. We tested physical stability and expression levels of plasmids carrying EBNA1 and oriP for episomal maintenance, immunoglobulin light chain enhancer elements for augmentation of expression, and cytokine or marker genes after introduction into human NHL cell lines in vitro and in vivo after inoculation into nude mice. Data obtained with these EBV-based vectors were compared with another plasmid, not carrying EBNA1 and oriP. cDNAs coding for GM-CSF, IL6, TNF alpha, the chloramphenicolacetyltransferase (CAT) and the beta-galactosidase (lacZ) gene were transfected into the EBV-positive Burkitt's lymphoma cell line BL60 and the EBV-negative B cell lymphoma cell line BJA-B. EBV-derived vectors permitted a high, host cell independent transfection efficiency and high and host cell independent levels of expression. After removal of the selection pressure (hygromycin B) cytokine expression could be detected for several weeks in vitro and in vivo but, however, declined continuously. These experiments suggest that episomal BC-derived vectors represent an effective tool for cytokine gene transfer in human lymphoma cells.
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PMID:Suitability of Epstein-Barr virus-based episomal vectors for expression of cytokine genes in human lymphoma cells. 908 10

Derivatives of the Edmonston-B strain of measles virus (MV-Ed) are safe, live attenuated measles virus (MV) vaccines that have been used worldwide for more than 30 years. The cytoreductive potential of MV-Ed has been investigated in murine models of both aggressive and indolent B-cell lymphoma in severe combined immunodeficient (SCID) mice. The rationale for these studies was generated by experience with viral fusogenic membrane glycoproteins as cytotoxic genes and the recognition of the potential of replicating viruses in the treatment of human malignancy. Intratumoral injection of both unmodified MV-Ed and a strain of MV-Ed genetically modified by the addition of a beta-galactosidase reporter gene (MVlacZ) induced regression of large established human lymphoma xenografts, in contrast to control therapy with UV-inactivated virus, in which all tumors progressed. The antitumor effect still occurred in the presence of passively transferred anti-MV antibody. Intravenous administration of MV also resulted in considerable slowing of tumor progression. Analysis of sections of residual tumor confirmed replication of MV within the tumors. Thus, the vaccine strain of MV mediates regression of large, established human B-cell lymphoma xenografts in SCID mice, and proof of principle is established that MV is oncolytic for lymphomas in vivo. Attenuated MVs may have value as a novel replicating-virus therapy for this group of disorders. (Blood. 2001;97:3746-3754)
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PMID:Live attenuated measles virus induces regression of human lymphoma xenografts in immunodeficient mice. 1138 12

Murine lymphocytes are relatively refractory to efficient transfection or retroviral gene transduction. Adenovirus has been used as a vector to transduce a wide variety of cell types. Several advantages of adenoviruses are their ability to transduce non-cycling cells and to transduce the majority of cells in a population. Unfortunately, lymphocytes are not susceptible to infection with conventional adenovirus. Therefore, to express genes efficiently in murine B cells, we tested the ability of genetically modified adenovirus to transduce the beta-galactosidase gene. We found that adenovirus containing polylysine in the fiber knob was able to efficiently transduce lipopolysaccharide (LPS)-activated splenic B cells and the B lymphoma line M12.4.1; greater than 80% of the cells expressed beta-galactosidase activity. However, small resting B cells did not express activity unless treated with LPS after infection. This transduction was mediated by interaction with charged molecules since heparan-sulfate, and to a lesser degree chondroitan sulfate, inhibited the transduction. In addition, adenovirus containing a FLAG epitope in the fiber protein was used to target the FcR expressed on B cells using an anti-FLAG antibody. In the presence of anti-FLAG, the modified adenovirus was able to efficiently transduce LPS-activated B cells and several B cell lymphoma lines. Interestingly, in the absence of anti-FLAG, there was low level transduction in the LPS-blasts and in M12.4.1 that was not inhibited by soluble adenovirus fiber protein or agents that block RGD-integrin interactions. These results demonstrate that modified adenovirus efficiently transduce B lymphocytes which will be critical for targeting genes to normal or malignant B cells.
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PMID:Efficient transduction of murine B lymphocytes and B lymphoma lines by modified adenoviral vectors: enhancement via targeting to FcR and heparan-containing proteins. 1142 34

Protein antigens have been covalently linked randomly to surface proteins on immature dendritic cells (DC). This has been achieved under physiological conditions using a heterobifunctional reagent that couples antigens to free thiol groups expressed on DC surface proteins. This results in a significant increase in the amount of antigen that is bound to DC, and the antigen/membrane protein complexes that are formed are rapidly internalized. DC, loaded covalently with either beta-galactosidase (beta-gal) or a tumor-associated immunoglobulin (Ig) when injected into mice, induce a beta-gal- or Ig-specific T cell response, and a protective anti-tumor immunity for tumors expressing either beta-gal or the targeted Ig. This response is shown here to be significantly greater than that which is induced by DC that are loaded with these antigens via the conventional antigen pulse protocol. These results establish a novel, safe, and viable approach of enhancing the effectiveness of DC-based vaccination strategies for B cell lymphoma.
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PMID:B cell tumor vaccine enhanced by covalent attachment of immunoglobulin to surface proteins on dendritic cells. 1618 29

The effect of p53-dependent cell-cycle arrest and senescence on Emu-myc-induced B-cell lymphoma development remains controversial. To address this question, we crossed Emu-myc mice with the p53(515C) mutant mouse, encoding the mutant p53R172P protein that retains the ability to activate the cell-cycle inhibitor and senescence activator p21. Importantly, this mutant lacks the ability to activate p53-dependent apoptotic genes. Hence, Emu-myc mice that harbor two p53(515C) alleles are completely defective for p53-dependent apoptosis. Both Emu-myc::p53(515C/515C) and Emu-myc::p53(515C/+) mice survive significantly longer than Emu-myc::p53(+/-) mice, indicating the importance of the p53-dependent non-apoptotic pathways in B-cell lymphomagenesis. In addition, the p53(515C) allele is deleted in several Emu-myc::p53(515C/+) lymphomas, further emphasizing the functionality of p53R172P in tumor inhibition. Lymphomas from both Emu-myc::p53(515C/515C) and Emu-myc::p53(515C/+) mice retain the ability to upregulate p21, resulting in cellular senescence. Senescence-associated beta-galactosidase (SA beta-gal) activity was observed in lymphomas from Emu-myc::p53(+/+), Emu-myc::p53(515C/515C) and Emu-myc::p53(515C /+) mice but not in lymphomas isolated from Emu-myc::p53(+/-) mice. Thus, in the absence of p53-dependent apoptosis, the ability of p53R172P to induce senescence leads to a significant delay in B-cell lymphoma development.
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PMID:p53-dependent senescence delays Emu-myc-induced B-cell lymphomagenesis. 1993