Binding of human tumor necrosis factor to high affinity receptors on HeLa and lymphoblastoid cells sensitive to growth inhibition

Purified human tumor necrosis factor (TNF) was iodinated to high specific activity with good retention of its biological activity, as determined by the cytotoxic titer on murine L929 cells. The binding of 125I-TNF to L929 and human HeLa S2 cells grown in monolayer was initially measured, but high levels of nonspecific binding were observed. Specific binding to high affinity receptors of HeLa S2 cells grown in suspension culture was demonstrated by competitive displacement experiments and analysis of the binding data with the LIGAND program. A KD of 2 X 10(-10) M and 6000 receptors/cell were calculated in this way. These observations provide the first direct evidence for a cellular receptor for TNF. The cell-bound 125I-TNF was internalized at 37 degrees C, presumably by receptor-mediated endocytosis, and subsequently degraded to acid-soluble products. Three lines of human lymphoblastoid cells were examined for sensitivity to the cytostatic effect of TNF and for the presence of high affinity receptors. Daudi and Raji cells were insensitive to TNF and showed very few specific binding sites when incubated with 125I-TNF. Jurkat cells were growth-inhibited by TNF and showed a significantly greater number of specific binding sites than the other lymphoblastoid cells. These findings suggest that the sensitivity of some cell lines to the biological effects of TNF may be correlated with the presence of a relatively high number of receptors for this factor.

Molecular cloning and expression of human tumor necrosis factor and comparison with mouse tumor necrosis factor

U-937 cells, a monocytic line derived from a human histiocytic lymphoma, were induced for human tumor necrosis factor (TNF) secretion into the medium and were used for the preparation of TNF mRNA. Biological activity of the latter was quantified in a Xenopus laevis oocyte injection system. TNF mRNA was enriched by gradient centrifugation and this size-fractionated mRNA was used for synthesis of cDNA and inserted into the unique PstI site of pAT153. A recombinant plasmid containing human TNF cDNA was selected by colony hybridization using an internal fragment of a mouse TNF cDNA clone [Fransen, L., Mueller, R., Marmenout, A., Tavernier, J., Van der Heyden, J., Kawashima, E., Chollet, A., Tizard, R., Van Heuverswyn, H., Van Vliet, A., Ruysschaert, M. R. & Fiers, W. (1985) Nucleic Acids Res. 13, 4417-4429] as a probe. The sequence of this human TNF cDNA is in agreement with the one published by Pennica et al. [Pennica, D., Nedwin, G. E., Hayflick, J. S., Seeburg, P. H., Derynck, R., Palladino, M. A., Kohr, W. J., Aggarwal, B. B. & Goeddel, D. V. (1984) Nature (Lond.) 312, 724-729]. The 157-amino-acid-long mature sequence is about 80% homologous to mouse TNF and its hydrophilicity plot is also very similar, in spite of the apparent species specificity of TNF. In contrast to mouse TNF, it contains no potential N-glycosylation site. When compared to other cytokines, like IFN-beta, IFN-gamma, or IL-2, there is a remarkably high preference for G X C pairs in the third-letter positions. Expression of the TNF cDNA in monkey COS cells or in Escherichia coli gives rise to a protein having similar biological and serological properties as natural human TNF. A human genomic clone was also identified and sequenced; it was found to be in good agreement with the one recently published by Shirai et al. [Shirai, T., Yamaguchi, H., Ito, H., Todd, C. W. & Wallace, R. B. (1985) Nature (Lond.) 313, 803-806], except for some differences in the introns and 5'-untranslated region.

Molecular cloning of mouse tumour necrosis factor cDNA and its eukaryotic expression

Tumour necrosis factor (TNF), released by induced macrophages, causes tumour necrosis in animals and kills preferentially transformed cells in vitro. mRNA induced in the established mouse monocytic PU 5.1.8 cell line by lipopolysaccharide, was converted into double-stranded cDNA and cloned in the pAT153 vector. Recombinant plasmids were screened by plus-minus hybridization and TNF-specific oligonucleotide probes constructed on the basis of partial amino acid sequences of rabbit TNF. A series of TNF specific clones were identified and confirmed by hybrid selection of mouse TNF-specific mRNA. The sequence codes for a 235 amino acids long polypeptide, of which 156 amino acids presumably correspond to the mature product. It can be concluded that mature mouse TNF is a glycosylated dimer. Biologically active TNF was secreted by both Cos-I and CHO-cells transfected with the chimaeric expression vector pSV2d2-mTNF containing the coding region of the mouse TNF cDNA gene.

CT and US findings in pancreatic ductal tumours. A report of an unusual case and review of the literature

Pancreatic cystadenomas and cystadenocarcinomas are rare tumours usually occurring in women. The first symptoms are pain, occasionally associated with a palpable tumour in the left upper quadrant, and in rare cases the clinical and laboratory findings are suggestive of a pseudocyst. US shows a cystic neoplasm with a wall enclosing several polypoid areas. CT allows the diagnosis of the type of septa within the cyst and shows the extension of the lesion and calcifications into the wall. It also permits the assessment of the probable pathological complications associated with the tumour; therefore CT cannot differentiate cystadenoma from cystadenocarcinoma. The analysis of these different phenomena is based on one observation and a review of the literature.

[Nephroblastoma with egg-shell peripheral calcifications. Apropos of 3 cases]

Three cases of nephroblastoma presented "egg-shell" peripheral calcifications of pseudocystic appearance of radiology. These peripheral lesions are compared with the more commonly reported central calcifications. Their pathology is unknown and they lack prognostic significance of any importance. As for all nephroblastomas the diagnosis is based on straight abdomen images, intravenous urography, ultrasound and computed tomography. Differential diagnosis is basically from renal adenocarcinoma in children, the latter often exhibiting similar calcifications, the distinction between the two types of tumor depending on age of onset. These calcified lesions are non-specific findings and various diagnoses are discussed.

[Computed x-ray tomography of abdominal lipoma and liposarcoma in adults. Apropos of 9 cases]

CT scans were performed in 9 patients with fatty tumors of the abdomen: 2 lipomas and 7 liposarcoma. Of primary retroperitoneal origin, five tumors had extended intraperitoneally. Scanning images typical for each type of tumor are described: lipomas are very hypodense and well circumscribed, with thin intratumoral septa; liposarcomas are less hypodense and contain thick septa which may coalesce and form large nodules. Scanner imaging provides precise data on tumor extension and allows early detection of recurrences of these fatty tumors.

Cloning and structure of the human interleukin 2 chromosomal gene

Southern hybridization using 32P-labelled human interleukin 2 (IL2) cDNA probes revealed the existence of a single human IL2 gene. Five clones containing the human IL2 chromosomal gene were isolated from two different human DNA libraries cloned in either lambda Charon 4A or L47 phages. Analysis of the clones showed that they contained different, overlapping portions of human DNA which were derived from the same chromosomal segment. Restriction fragments which hybridized with labelled IL2 cDNA probes were subcloned into plasmid pUR250 and the sequence and organization of the IL2 gene was determined. It contains three introns, 90 bp, +/- 2400 bp and +/- 1900 bp in length, respectively. The organization of the genomic clone resembles that of another lymphokine, interferon-gamma, but no clear homology was found by comparing either the coding sequence or the 5'- and 3'-flanking sequences of the two genes.

Molecular cloning of human interleukin 2 cDNA and its expression in E. coli

A recombinant plasmid containing human interleukin 2 (IL2) cDNA was identified in a cDNA library constructed from mRNA derived from PHA-TPA induced splenocytes. Using this cDNA as a hybridization probe, a DNA fragment containing the IL2 gene was isolated from a collection of hybrid phages derived from human genomic DNA. A unique reading frame was identified from the nucleotide sequence derived from these plasmids coding for a polypeptide of 153 amino acids and containing a putative signal sequence of 20 amino acids. A mature polypeptide starting with either Met-Ala-Pro or Met-Pro was expressed in E. coli under control of the E. coli trp promoter or using a combination of the phage lambda PL promoter and a ribosome binding site derived from phage Mu. The bacterial IL2 polypeptide had a molecular weight of 15,000 daltons and accounted for more than 10% of the total E. coli proteins in fully induced cells; it was biologically active in the T-cell specific DNA synthesis assay, even after recovery from a SDS-containing polyacrylamide gel.

[Role of scanography in the diagnosis of parathyroid adenomas. Apropos of 27 cases]

Scanner imagine pre-operatively in 27 patients with hyperparathyroidism provided assessment of the sensitivity (92 p.cent) and diagnostic precision (92.5 p.cent) of this investigational method. The need for a strict methodology and the advantages gained by high resolution and angioscanning programmes are emphasized. After analyzing the results, a review of the published literature enables the advantages and the limits of the scanner X to be defined, and a strategy for exploration of parathyroid adenomas to be proposed.

Human fibroblast interferon RNA transcripts of different sizes in poly(I).poly(C) induced cells

Northern blot analysis reveals that total RNA from human fibroblastoid cells (MG 63) induced with poly(I).poly(C) under conditions of IFN-beta production, contains predominantly a +/- 1,200 nucleotide long poly (A) mRNA (mRNA.M) which hybridizes with a Hu IFN-beta cDNA specific probe. But hybridization with this probe also enabled the detection of a polyadenylated RNA (RNA.I) with a length of between 3.5 kb-3.8 kb, representing 0.6% of the total hybridizable cellular RNA in superinduced cells. Mapping shows that the RNA.I contains all the sequence information present in mRNA.M. Furthermore, it also hybridizes to sequences, located downstream from the IFN-beta gene up to 2.5 kb beyond its poly A attachment site, while no hybridization to fragments located upstream of the IFN-beta mRNA cap site was observable. Hence this RNA.I corresponds to a transcript that starts at the same position as the major mRNA.M but which extends up to 2.5 kb beyond the 3'-end of mRNA.M where another polyadenylation signal is located.

Deletion mapping of the inducible promoter of human IFN-beta gene

Human fibroblast cells produce beta-type interferon only in response to viral infection or treatment with an inducer such as poly(rI) X poly(rC); this event is most probably controlled at the transcriptional level (for review see ref. 1). To study the induction process, we inserted the human fibroblast interferon (IFN-beta) gene, with or without its promoter region, into recombinant simian virus 40 (SV40) plasmid vectors which subsequently were transfected into monkey AP-8 cells. We report here that upon induction with poly(rI) X poly(rC) there was a 10-30-fold increase in IFN-beta synthesis. This inducer had no effect on interferon production when the coding region only was inserted into the vector plasmid, which indicates that the promoter region is required for inducibility of this gene. Deletion mapping implicates the region between nucleotides -144 and -186 from the mRNA initiation site in the specific regulation of the IFN-beta gene. This region contains a sequence that is remarkably homologous with a consensus sequence found in the 5' flanking region of steroid hormone responsive genes, which might be involved in binding the progesterone-receptor complex.

The human fibroblast and human immune interferon genes and their expression in homologous and heterologous cells

The genetic information coding for human fibroblast interferon (IFN-beta) has been cloned both as a DNA copy (cDNA) and as a genomic clone. Human IFN-beta is made as a precursor and consists of a signal sequence 21 amino acid residues long followed by the mature protein 166 amino acids long. A single site for glycosylation is present. The human IFN-beta gene does not contain introns. Transfection of monkey cells with a chimeric SV40 derivative containing the human IFN-beta cDNA clone under control of the late SV40 promoter leads to secretion of high levels of IFN-beta. When a genomic clone is used in the same vector, IFN-beta synthesis can be further enhanced up to 30-fold by treatment with poly(rI) . poly(rC); this shows that a cis-active control element is present in the clone. An efficient expression system in Escherichia coli was worked out based on a plasmid containing the promoter PL of bacteriophage lambda, which is regulated by a temperature-sensitive repressor. This promoter is followed by a segment derived from bacteriophage MS2 that contains the ribosome-binding site of the replicase gene. The latter, however, is replaced by the human IFN-beta gene. Upon induction, high levels (about 5 x 10(9) IU 1(-1)) of IFN-beta are synthesized by the bacteria; this corresponds to about 2% of the total bacterial protein. The human immune (type II) interferon (IFN-gamma) gene has similarly been cloned. Partly purified mRNA derived from human spleen cells that had been induced with staphylococcal enterotoxin A was used as starting material. A full-length cDNA clone was sequenced. The total cDNA sequence is about 1150 nucleotides long; it contains a single open reading frame coding for 166 amino acids, the first 20 of which constitute the transmembrane signal. There are two sites for glycosylation. The amino acid sequence is quite different from that of IFN-alpha or IFN-beta, although a few similarities can be noted. The untranslated 3'-terminal region is about 550 nucleotides long. The IFN-gamma gene was expressed in monkey cells, again by using the SV40-derived vector, and the secreted product was characterized as true human IFN-gamma. A genomic clone in the form of a bacteriophage lambda derivative was also obtained. The IFN-gamma gene extends over at least 5 kilobases and contains at least two introns.

[Diagnostic reliability and economic profitability of 105 mm photography in digestive radiology]

A strict methodology using data-processing programmes was employed to compare diagnostic reliability and economic profitability of 105 mm photography and conventional radiography during 500 radiological examinations of the digestive tract. Films were evaluated twice on two separate occasions to determine correlation with predicted diagnosis and the amount of film exposed during the two investigational methods. Results demonstrated that a reliable diagnosis could be established with 105 mm photography (sensitivity: 97, 4 p. cent; specificity: 90 p. cent; diagnostic precision: 94 p. cent), that it was economically profitable (economy of 1 m2 of sensitized film surface at each examination), and that productivity was improved by the use of this method.

[Scanography and chemonucleolysis of herniated discs. Value and limitations in 20 cases]

Scanography explorations were conducted before and after chemonucleolysis in 20 patients with sciatica from herniated discs. The scanner can improve the selection of patients for this new type of medical treatment by detecting adverse factors: stenosed discs, excluded hernias, narrow canals, stenosis of the lateral recesses. The diagnostic precision of scanography can be demonstrated by comparison of results with those obtained by discography. Following chemonucleolysis, however, intravenous injection of a contrast medium and a high resolution programme are necessary to obtain specific information from scanography.

Cloning and structure of the human immune interferon-gamma chromosomal gene

Two clones containing the human immune interferon-gamma (IFN-gamma) chromosomal gene were isolated from a human DNA library present in lambda Charon4A phage. DNA from these clones specified biologically active interferon upon injection into the nuclei of Xenopus laevis oocytes. Analysis of the clones revealed that they were derived from the same chromosomal segment. Restriction fragments that hybridized with 32P-labeled cDNA probes were subcloned into plasmids and the complete sequence of the IFN-gamma gene was determined. Unlike IFNs-alpha and -beta, IFN-gamma does contain introns. Their presence was also revealed by electron microscopy. It is intriguing that the smallest of the three introns is located just in the middle of the Glu-Glu sequence which is conserved among all three forms of interferon at approximately the same position. The promoter region was found to contain a prototype TATA box, many palindromic structures and several repeating sequences and two symmetrical structures. Particularly interesting was the existence of two sequences homologous to those present in the chicken albumin and the human IFN-beta gene promoter region. A sequence GTGTTG common to several other genes was found in the region approximately 10 nucleotides downstream from the polyadenylation site.

Isolation and characterization of a human fibroblast interferon gene and its expression in Escherichia coli

Human fibroblasts were induced for interferon synthesis, and the mRNA coding for interferon was partially purified. On this basis, double-stranded DNA copies were synthesized enzymatically and were inserted into cloning vehicles. A large collection of colonies containing chimeric plasmids was obtained. An RNA selection method was used for the identification of several individual clones containing the human fibroblast interferon (IFN-beta) cDNA. From the nucleotide sequence of the cloned structural gene, the primary structure of the mRNA and, hence, of the protein itself was deduced. IFN-beta is a polypeptide 166 amino acids long and contains a single site for N-glycosylation; IFM-beta is normally made as a preinterferon containing a signal sequence that is 21 amino acids long. The interferon gene was inserted into an expression plasmid under thermoinducible control of the phage lambda PL promoter. this allowed the synthesis of polypeptides in the bacteria, which for all physicochemical, biological, and immunologic properties tested closely resembled authentic IFN-beta.