Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mycobacterium leprae lives free in the cytoplasm in infected macrophages. To test if an M. leprae antigen released into the cytoplasm would associate with major histocompatibility complex (MHC) class II we introduced the gene encoding the 65 kDa heat-shock protein (ML65hsp) into a retroviral shuttle vector (pZIPNeoSV(X)) and transfected the murine macrophage cell line J774G8. S1 nuclease mapping and Western blot analysis of the transfected cell line (CJ11) showed that specific messenger RNA and ML65hsp antigen were stably expressed. Presence of antigen at the cell surface was demonstrated by flow cytometric analysis with specific monoclonal antibodies (mAb). Antigen-specific T lymphocytes were stimulated by CJ11 cells to proliferate and release interleukins (IL-2 and IL-3). These responses were blocked by mAbs specific for either MHC class II or for the mycobacterial antigen. The endogenous antigen was also recognised by MHC class I-dependent cytotoxic T cells; cytotoxicity was inhibited by mAbs against either MHC class I molecules or ML65hsp. Thus, production of ML65hsp within the host cytoplasm resulted in association of the antigen with both MHC class I and MHC class II antigen-presenting structures and evoked both lymphocyte proliferation and cytotoxicity towards the antigen-presenting cell. These findings may be relevant to the development of recombinant subunit vaccines against intracellular pathogens.
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PMID:Mycobacterium leprae 65hsp antigen expressed from a retroviral vector in a macrophage cell line is presented to T cells in association with MHC class II in addition to MHC class I. 156 Jul 52

Using a monoclonal antibody to the interleukin 3 (IL-3) receptor (anti-Aic2), we isolated a cDNA (AIC2B) from a mouse mast cell line which is homologous to the previously characterized gene for the IL-3 receptor (AIC2A). This cDNA encodes a polypeptide of 896 amino acid residues and has 91% amino acid sequence identity with the IL-3 receptor. A consensus sequence defining an additional cytokine receptor family is present in this clone. Compared to the AIC2A clone, the AIC2B cDNA encodes a protein with amino acid substitutions, insertions, and deletions dispersed throughout the entire protein. Oligonucleotide probes specific for each cDNA hybridized with different genomic fragments, indicating that the AIC2A and AIC2B proteins are encoded by two distinct genes. Fibroblasts transfected with the AIC2B cDNA expressed the protein at the cell surface as determined by binding with the anti-Aic2 antibody but did not bind IL-3 or other cytokines, including IL-2, IL-4, granulocyte-macrophage colony-stimulating factor, erythropoietin, and IL-9 (p40) at concentrations between 1 and 10 nM. An S1 nuclease protection assay was used to discriminate between the AIC2A and AIC2B transcripts. We found that the AIC2B gene was coexpressed with the AIC2A gene. These results suggest a potential involvement of AIC2B in cytokine signal transduction.
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PMID:Cloning and expression of a gene encoding an interleukin 3 receptor-like protein: identification of another member of the cytokine receptor gene family. 169 79

B cells can be activated by T-independent antigens or mitogens such as lipopolysaccharide (LPS) which will induce proliferation and differentiation of the B cells into Ig-secreting cells, without the intervention of T cells. The precise mechanism of T-independent proliferation and differentiation of B cells is still unclear. It is possible however that antigen-stimulated B cells may produce some factors which play a role in T-independent B-cell responses. In addition, since it has now been established that B cells can function as antigen-presenting cells, it is possible that they too secrete a molecule which is involved in the activation of T cells, analogous to IL-1 production by antigen-presenting macrophages. A number of human B-cell lines, as well as human normal B cells activated appropriately, have been shown to produce various cytokines, and similar studies are now being undertaken in the mouse. In the present study, six cloned murine B-cell lymphomas of different origin were analyzed for the presence of mRNA encoding a number of lymphokines by hybridization of specific cDNA probes to poly-A RNA, followed by the sensitive S1 nuclease digestion technique. The lymphokines included (IL-) 1, 2, 3, 4, 5, and neuroleukin. Whereas none of the lines expressed detectable levels of IL-2, IL-3, or IL-5 mRNA, all the lines expressed high levels of neuroleukin mRNA. Three of the lymphomas (CH12, CH31, and NBL) expressed low levels of IL-1 mRNA. The most striking finding was that one lymphoma, CH12, constitutively expressed IL-4 mRNA. This mRNA appeared to be functional, as IL-4 activity measured by the HT-2 T cell proliferation assay could be detected in supernatants collected from CH12 cells. The growth-inducing activity of CH12 supernatant on HT-2 cells could be completely blocked by an anti-IL-4 monoclonal (11B11), but not by an anti-IL-2 antibody (S4B6), consistent with our observations that CH12 cells produce IL-4 but not IL-2. CH12 cells were also found to express high affinity receptors for IL-4. Proliferation of CH12 cells was not affected by the addition of exogenous IL-4. Addition of anti-IL-4 antibodies to CH12 cells in culture caused a slight but reproducible increase in their proliferation at low cell numbers, which is probably not highly significant. These findings open the possibilities that murine B lymphocytes are capable of lymphokine production or alternatively that aberrant lymphokine production underlies B-lymphocyte transformation.
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PMID:Constitutive production of lymphokines by cloned murine B-cell lymphomas--CH12 B lymphoma produces interleukin-4. 278 29

We produced the T cell hybridoma D9C1.12.17 by fusing an IL-4-producing T cell clone D9.1Hi with the AKR thymoma BW5147. The resulting hybridoma produced IL-2 as well as IL-4 even though none of the parental cells produced IL-2 after stimulation with Con A. The production of IL-2 was confirmed at the mRNA level by using an S1 nuclease protection assay. Further analysis indicated that Con A-induced IL-2 production was a common phenomenon among T cell hybridomas derived from this fusion. Although BW5147 does not produce detectable lymphokines after Con A stimulation, this line was able to produce IL-2, granulocyte-macrophage colony stimulating factor, and small amounts of IL-3 and IFN-gamma when stimulated with calcium ionophore and phorbol ester. The latter agents are thought to mimic the activating signal(s) delivered through the Ag:MHC TCR. This observation indicates that BW5147 has the ability to produce lymphokines but may lack component(s) which couple the extracellular signal to lymphokine production, and suggests that in T cell hybridomas, part of the spectrum of lymphokines produced may be contributed by BW5147.
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PMID:The AKR thymoma BW5147 is able to produce lymphokines when stimulated with calcium ionophore and phorbol ester. 312 29

We have isolated cDNA clones encoding human IL-3 from libraries constructed in a modified pcD mammalian expression vector by using mRNA prepared from activated human T cell clones. Amino acid sequence of human IL-3 deduced from DNA sequence of these cDNA clones agrees with that predicted from genomic sequence except at amino acid position 27. Northern blotting analysis and S1 nuclease analysis show that almost all activated T cell clones express IL-3 mRNA with kinetics similar to that observed in mouse T cell clones. However, striking difference was found in the level of granulocyte-macrophage-CSF and IL-3 mRNA expressed in activated human T cells. In contrast to mouse T cell clones, granulocyte-macrophage-CSF mRNA is expressed at least two orders of magnitude more abundant than IL-3 mRNA. Yeast Saccharomyces cerevisiae carrying human IL-3 cDNA fused downstream to alpha-factor leader sequence expressed and secreted biologically active IL-3. Several different rat anti-peptide antisera have been used to confirm the presence of human rIL-3 immunochemically. The immunoreactive human IL-3 expressed in transiently transfected COS7 cells or in yeast was observed to be heterogeneous. Human rIL-3 expressed in COS7 cells has multipotential CSF activity in semisolid cultures of bone marrow cells, and selectively induced the proliferation of My-10+ marrow or cord blood cells in liquid cultures.
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PMID:Isolation and characterization of an expressible cDNA encoding human IL-3. Induction of IL-3 mRNA in human T cell clones. 312 63

We analyzed the effect of several growth factors and cytokines on the expression of amyloid beta protein precursor (APP) mRNAs in cultured mouse neuronal and glial cells. In neuronal cultures from embryonic day-15 brain. Northern blotting revealed that APP mRNAs increased by 1.3- to 2.6-fold when treated with nerve growth factor, basic fibroblast growth factor, interleukin 1, interleukin 2, interleukin 3, interleukin 6 or granulocyte-macrophage colony-stimulating factor but not with tumor necrosis factor alpha. An S1 nuclease protection assay revealed that the enhanced APP mRNA in neuronal cultures was exclusively APP695 mRNA. On the other hand, astrocyte-enriched cultures prepared from postnatal day-2 brain did not show any significant alteration among these factors. We conclude that certain growth factors and cytokines could enhance APP 695 mRNA expression in neurons in vitro.
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PMID:Effect of growth factors and cytokines on expression of amyloid beta protein precursor mRNAs in cultured neural cells. 847 81