High-level expression in Escherichia coli of a soluble and fully active recombinant interleukin-1 beta

A complementary DNA sequence encoding monocyte interleukin-1 (IL-1), beta form/pI7, was expressed in Escherichia coli. Recombinant plasmid pDP516 was constructed by cloning and rebuilding the mature IL-1 coding sequence into an E. coli expression vector. Bacteria transformed with pDP516 constitutively produced recombinant IL-1 (r-IL-1) at 15-20% of total E. coli protein. The r-IL-1 was found to be in the soluble fraction of sonicated E. coli Bacterial r-IL-1 (DP516) has been purified to homogeneity by anion exchange and sizing column chromatography, with an apparent molecular weight of 17,500. The identity of the purified r-IL-1 was confirmed by amino acid and DNA sequencing analyses. Purified recombinant IL-1 DP516 exhibits biological activity similar to that of native monocyte IL-1 (3 approximately 4 X 10(7) units/mg). An amino-terminal deletion mutant completely abolishes the biological activity, indicating that the integrity of the IL-1 molecule might be important for its function.

Natural cytotoxic cells and tumor necrosis factor activate similar lytic mechanisms

The lytic activity of natural cytotoxic (NC) cells has several characteristics which clearly distinguish it from other cell-mediated lytic activities and from most soluble cytolytic factors. An exception is the lytic activity mediated by tumor necrosis factor (TNF). In this paper, we report a detailed comparison of NC and TNF lysis of target cells which are used as prototype NC targets or TNF targets, and show that the two cytolytic activities have very similar, if not identical, lytic mechanisms. We present data showing that target cells which are NC-sensitive are also TNF-sensitive and that target cells which are NC-resistant are also TNF-resistant. Moreover, cells selected either in vivo or in vitro for NC resistance are selected for TNF resistance, and cells selected for TNF resistance are selected for NC resistance. The analysis of the kinetics of 51Cr release mediated by NC cells or by TNF show that both activities affect similar kinetics, in that there is no cell lysis for several hours after targets and effectors first interact. However, NC and TNF lytic activities can be distinguished. By using the cell lines 10ME or B/C-N as targets, it can be shown that whereas NC-mediated lysis is dependent on protein synthesis, TNF-mediated lysis is not. We also show that targets which are resistant to NC-mediated lysis because they express a protein synthesis-dependent resistance mechanism also require protein synthesis to resist TNF-mediated lysis, suggesting that the same resistance mechanism protects cells against both NC cells and TNF. Together, these data strongly support the hypothesis that NC cells and TNF activate the same lytic mechanism within target cells and that TNF may mediate the lytic activity of NC effector cells.

Natural cytotoxic cells and tumor necrosis factor activate similar lytic mechanisms

The lytic activity of natural cytotoxic (NC) cells has several characteristics which clearly distinguish it from other cell-mediated lytic activities and from most soluble cytolytic factors. An exception is the lytic activity mediated by tumor necrosis factor (TNF). In this paper, we report a detailed comparison of NC and TNF lysis of target cells which are used as prototype NC targets or TNF targets, and show that the two cytolytic activities have very similar, if not identical, lytic mechanisms. We present data showing that target cells which are NC-sensitive are also TNF-sensitive and that target cells which are NC-resistant are also TNF-resistant. Moreover, cells selected either in vivo or in vitro for NC resistance are selected for TNF resistance, and cells selected for TNF resistance are selected for NC resistance. The analysis of the kinetics of 51Cr release mediated by NC cells or by TNF show that both activities affect similar kinetics, in that there is no cell lysis for several hours after targets and effectors first interact. However, NC and TNF lytic activities can be distinguished. By using the cell lines 10ME or B/C-N as targets, it can be shown that whereas NC-mediated lysis is dependent on protein synthesis, TNF-mediated lysis is not. We also show that targets which are resistant to NC-mediated lysis because they express a protein synthesis-dependent resistance mechanism also require protein synthesis to resist TNF-mediated lysis, suggesting that the same resistance mechanism protects cells against both NC cells and TNF. Together, these data strongly support the hypothesis that NC cells and TNF activate the same lytic mechanism within target cells and that TNF may mediate the lytic activity of NC effector cells.

Analysis of demand conditions associated with stereotypy

Possible escape/avoidance functions of stereotypic behavior were investigated in a classroom setting using functional academic tasks. A 6-year-old boy's stereotypic mouthing was assessed during high vs low response activities, familiar vs novel activities and avoidance vs partial-avoidance conditions. Results showed that stereotypy occurred at higher rates during more difficult activities (i.e. those that were novel or required a greater number of responses), and when stereotypy was allowed to effect a delay in instructional demands. Treatment procedures based on these analyses were implemented by the classroom teacher and shown to be effective.

The cloned cell line L10A2.J expresses natural cytotoxic activity

The analysis of natural cytotoxicity (NC) has been hampered by the lack of cloned NC effectors. In studies reported here we show that the cloned cell line L10A2.J expresses properties similar to those of splenic NC effectors. L10A2.J cells lyse NC-sensitive targets, but do not lyse NC-resistant targets which are sensitive to lysis by natural killer (NK) or cytotoxic T lymphocytes. The mechanism by which L10A2.J cells lyse NC-sensitive targets is similar to the lytic mechanism of splenic NC effectors in that both result in the release of 51Cr from targets with a lag of 5-7 hr after effectors and targets are mixed. In addition, inhibition of protein synthesis during the in vitro assays of NC or L10A2.J lytic activity causes some NC-resistant targets to become sensitive to lysis by both NC and L10A2.J effectors. The only functional difference detected between L10A2.J and splenic NC effectors is in their recognition of targets. While L10A2.J and splenic NC effectors recognize many of the same targets (NC resistant and NC sensitive), L10A2.J, unlike splenic NC effectors, does not recognize the NK-sensitive cell line YAC-1.

Human T lymphocytes express a protein-tyrosine kinase homologous to p56LSTRA

We have used oligonucleotide probes, based on a portion of the p60v-src autophosphorylation sequence, Glu-Asp-Asn-Glu-Tyr-Thr, to identify and characterize a cDNA from the human T-leukemia cell line, JURKAT. The JURKAT cDNA (designated ptk-JURKAT) was homologous to but distinct from the src, yes and fgr oncogenes, which encode protein-tyrosine kinases (ATP:protein phosphotransferase, EC 2.7.1.37). The ptk-JURKAT cDNA hybridized with a 2.2 kb RNA transcript from JURKAT cells and the human T-cell lymphoma line, MOLT-4, but failed to identify any transcript in two human B-cell lymphoma lines or a human erythroid-myeloid leukemia line, K562. Recently the nucleotide sequence has been established for the murine lymphocyte protein tyrosine kinase, p56LSTRA. The ptk-JURKAT cDNA appears to encode the human homolog of p56LSTRA.

Dissociation of contact-noninhibition in vitro and tumorigenicity in vivo

For cell lines, the correlation of the in vitro expression of contact-inhibition to the in vivo expression of the nontumorigenic phenotype, and the correlation of the expression of contact-noninhibition (i.e., focus formation) to the expression of the tumorigenic phenotype are commonly used as a means to identify, in vitro, cells which presumably have undergone malignant transformation such that, if tested, they would grow as tumors in vivo. In this report we show that while this correlation is true for contact-noninhibited transformants induced by benzo(a)pyrene (BP), a DNA mutating and demethylating agent, it is not true for contact-noninhibited transformants induced by 5-azacytidine (AZC), a DNA demethylating agent which does not have mutagenic activity. The in vitro treatment of a contact-inhibited cell line with 5-azacytidine (AZC) results in the expression of contact-noninhibited transformants, which, in vitro quantitatively and qualitatively similar to those induced by BP but unlike BP, treatment with AZC does not result in the in vivo expression of tumorigenicity.

In vivo or in vitro selection for resistance to natural cytotoxic cell lysis selects for variants with increased tumorigenicity

Experiments were designed to test the hypothesis that transformed cells that are NC sensitive must escape NC activity if they are to grow as tumors in normal individuals. NC-resistant variants were selected either in vivo or in vitro from NC-sensitive cell lines that grow as tumors in immunodeficient mice but not in syngeneic normal mice. The tumorigenicity of cloned NC-resistant variants was compared with the parental cell lines and to cell lines that went through the selection procedure, but after cloning remained NC sensitive. Cloned NC-resistant cell lines derived from tumors that developed in x-irradiated nude mice after the injection of an NC-sensitive cell line are tumorigenic in normal mice, whereas cloned NC-sensitive cell lines derived from the same tumors are unable to grow as tumors in normal mice. Similarly, six of seven NC-resistant cloned cell lines independently isolated after in vitro selection for NC-resistance are tumorigenic in normal mice, whereas cloned NC-sensitive cell lines isolated from the same in vitro selected populations are not tumorigenic in normal mice. Thus, either the in vivo or in vitro selection of NC-resistant cells selects for cells tumorigenic in normal mice; these findings, along with our previous observations that selection for cells tumorigenic in normal mice selects for NC resistance, provide compelling evidence that escape from NC activity is required before some transformed cells can grow as tumors in normal mice.

In vivo or in vitro selection for resistance to natural cytotoxic cell lysis selects for variants with increased tumorigenicity

Experiments were designed to test the hypothesis that transformed cells that are NC sensitive must escape NC activity if they are to grow as tumors in normal individuals. NC-resistant variants were selected either in vivo or in vitro from NC-sensitive cell lines that grow as tumors in immunodeficient mice but not in syngeneic normal mice. The tumorigenicity of cloned NC-resistant variants was compared with the parental cell lines and to cell lines that went through the selection procedure, but after cloning remained NC sensitive. Cloned NC-resistant cell lines derived from tumors that developed in x-irradiated nude mice after the injection of an NC-sensitive cell line are tumorigenic in normal mice, whereas cloned NC-sensitive cell lines derived from the same tumors are unable to grow as tumors in normal mice. Similarly, six of seven NC-resistant cloned cell lines independently isolated after in vitro selection for NC-resistance are tumorigenic in normal mice, whereas cloned NC-sensitive cell lines isolated from the same in vitro selected populations are not tumorigenic in normal mice. Thus, either the in vivo or in vitro selection of NC-resistant cells selects for cells tumorigenic in normal mice; these findings, along with our previous observations that selection for cells tumorigenic in normal mice selects for NC resistance, provide compelling evidence that escape from NC activity is required before some transformed cells can grow as tumors in normal mice.

Plant regeneration from mesophyll protoplast culture of cabbage (Brassica oleracea var 'capitata')

Protoplasts were enzymatically isolated from the first leaves of cabbage (Brassica oleracea var 'capitata', F1 hybrid 'Baochun'). Sustained cell division and somatic embryogenesis were obtained after culturing the protoplasts in modified liquid DPD medium supplemented with CaCl2 · 2H2O 800 mg/l, 2,4-D 0.5 mg/l, kinetin 1 mg/l, 0.3 M mannitol and sucrose 20 g/l. Upon transferring cell colonies onto a modified Murashige and Skoog (MS) agar medium, small calli were gradually formed. Callus proliferated on MS medium supplemented with hormone combinations of 2,4-D 0.1-0.5 mg/l and kinetin 3-4 mg/l. Multiple shoots were induced on differentiation medium supplemented with 3 mg/l of kinetin and 0.1 mg/l of gibberellic acid GA3. After transferring differentiated shoots onto MS medium supplemented with indoleacetic acid (IAA), kinetin, GA3 at 0.1 mg/l each and 500 mg/l of N.Z. amine, intact plants were eventually produced.

A viral long terminal repeat in the interleukin 2 gene of a cell line that constitutively produces interleukin 2

The gibbon leukemia cell line MLA 144 differs from every other T-lymphocyte line in that it constitutively makes interleukin 2 (IL-2) (also called T-cell growth factor) without stimulation by antigen, lectin, or tumor promoters. Previous work in which glucocorticoids were used to inhibit IL-2 production has indicated that proliferation of this cell line is dependent upon endogenously produced IL-2. We have found that the MLA 144 cell line has a copy of the gibbon leukemia virus inserted into the 3' nontranslated region of the IL-2 gene. This integration event produces a composite mRNA made up of the protein coding sequences of the IL-2 gene transcript but incorporating the viral long terminal repeat (LTR) in the 3' nontranslated region of the mRNA. This composite mRNA transcript uses the polyadenylylation signal in the viral 5' LTR and incorporates the viral transcriptional control regions. The integration event must involve only one allele of the IL-2 gene, since transcripts essentially identical to normal human IL-2 mRNA are also produced in cloned sublines of MLA 144. That the viral LTR contains a 94-base-pair repeat reminiscent of enhancer sequences in several viruses suggests that the integration of the viral LTR at the 3' end of the IL-2 gene is responsible for the constitutive production of IL-2 in the MLA 144 cell line.

Analysis of immune surveillance of sequentially derived cell lines that differ in their tumorigenic potential

The immune surveillance hypothesis suggests that cancer evolves as a multistage process. Further, it predicts that cells intermediate on the pathway to cancer are susceptible to host protective mechanisms, and only those variants that are able to escape the protective mechanisms are able to grow as tumors. We have isolated, as lineages, fibroblast lines that express phenotypes predicted by the surveillance hypothesis. The lineages were derived by treating nontransformed cells (N-cells) with chemical carcinogens and by isolating transformed variants in vitro. From the transformants that are tumorigenic in immune-depressed ATXFL mice but rejected by normal mice (I-cells), variants were selected in vivo that had escaped the rejection mechanism(s) and had grown as tumors in normal mice (C-cells). Thus lineages were established comprised of sequentially derived cell lines with the following phenotypes: nontransformed, transformed but susceptible to host protective mechanisms, transformed and resistant to host protective mechanisms (i.e., N----I----C). With the use of in vivo cross-protection experiments, two independently derived I-cell lines were shown to express non-cross-reactive antigens that are not expressed by the parental nontransformed N-cells (i.e., transformation-associated antigens). The transformation-associated antigens are expressed at an equivalent level on the cells that are susceptible to rejection (i.e., I-lines) and those that have escaped rejection (i.e., C-lines). In addition, although the transformation-associated antigens expressed by I-cells induce an effective immune response capable of rejecting both the I-line and C-line, the expression of these antigens on C-cells does not induce an effective immune response. The role of host defense mechanisms in the rejection of these chemically transformed I-cells and the possible mechanisms by which C-cells escape rejection are discussed.

In situ hybridization of putative somatostatin mRNA within hypothalamus of the rat using synthetic oligonucleotide probes

The distribution of mRNA with high sequence homology to somatostatin mRNA within the periventricular hypothalamus of rat was assessed using in situ hybridization techniques with synthetic oligodeoxyribonucleotide probes, complementary to the 3' coding region of rat somatostatin mRNA. The probes (22- and 24-mers) were 5'-end labeled using T4 polynucleotide kinase and gamma-32P-ATP. They were used either individually or after ligation with T4 DNA ligase to form a 46-mer. Serial tissue sections (less than 10 microns) were taken from the level of the preoptic/anterior hypothalamus through the paraventricular hypothalamus. In situ hybridizations were conducted at room temperature in hybridization buffer. Neurons immunoreactive with antiserum raised against somatostatin were identified in alternate sections using standard immunocytochemical procedures. The anatomical location of the hybridization signal was determined by autoradiography. Our results show that the peri- and paraventricular hypothalamus is rich in transcripts putatively coding for somatostatin and that these transcripts are co-distributed with neurons immunoreactive with antisomatostatin immunoglobulin.

Induction of interleukin 2 messenger RNA inhibited by cyclosporin A

Cyclosporin A blocked production of the lymphokine interleukin 2 by activated T lymphocytes. In a human and a murine cell line this inhibition reflected an absence of interleukin 2 messenger RNA. Under conditions in which these cells are normally stimulated to secrete high levels of interleukin 2, they failed to do so in the presence of cyclosporin A. In both cell lines this failure was accompanied by an absence of interleukin 2 messenger accumulation.

Winter flounder antifreeze proteins: a multigene family

The nucleotide sequence of a cDNA clone of winter flounder antifreeze protein was determined by the dideoxynucleotide method. The sequence would predict a protein of 91 amino acids composed of a prepropeptide of 38 amino acids and a mature protein of 53 amino acids, which includes four complete 11-amino acid repeats. This predicted sequence corresponds to an antifreeze protein of intermediate size which is one 11-amino acid repeat longer than the smallest antifreeze proteins found in the serum of winter flounder during the cold season. Southern blot hybridization analysis of winter flounder genomic DNA with radioactive cDNA probes reveals a multigene family of potential antifreeze protein genes. This conclusion is supported by amino acid sequence analysis of several serum antifreeze proteins.

Ultrastructural changes of bone marrow megakaryocytes in several types of injury

Seventy-one dogs were used in this study. Bone marrow tissues were examined by LM and EM and the peripheral blood platelets were counted. On the basis of previous research, megakaryocytophagia in bone marrow was confirmed. It was also proved that neutrophilic granulocytes participate in the autophagocytosis reaction in the body. Megakaryocytophagia plays a major role in the elimination of degenerate megakaryocytes in the marrow. The pathological change in megakaryocytes is considered to be one of the important causes of decrease in number and impairment of function of the platelets in burn, blast injury and burn-blast combined injury.

Synthesis of 3,6-bis(aminoalkoxy)acridines and their effect on the immune System

A series of 3,6-bis(aminoalkoxy)acridines (2) was prepared and shown to have a protective antiviral effect against an interferon-sensitive virus (Columbia SK) and to partially restore an antibody response to a T-cell-dependent antigen in leukemic immunosuppressed mice. The presence of circulating interferon and the stimulation of natural killer cell activity in mice was observed for 21.