IE902930A1 - Human gp130 protein - Google Patents

Description

(1) Field of the Invention The present invention relates to a human gpl30 protein, which ie a protein participating in the transmission of an IL-6 signal, a DNA coding for thia protein, and a meane for and a method of producing thia protein by genetic engineering. (2) Description of the Related Art Interleukin-6 (IL-6) ie a protein participating broadly in the proliferation and differentiation of an organism, and ie characterized in that the protein plays an important role in defense system of an organism such as immunity, hematopoiesis or inflammation (see Kishimoto, Blood, 74, page 1, 1989).

It is reported that an abnormal production of IL-6 may become a factor in the cause of various autoimmune diseases (see Kishimoto and Hirano, Ann. Rev. Immunol., page 485, 1988).

Tha (nwentnri lenl atari a gana fnr hnw»n TLi receptor on the cell membrane, which is specifically bonded to human IL-6, and determined the primary structure thereof (see Japanese Patent Application NO. 63-194885). Then the inventors isolated a gene of mouse IL-6 receptor on the cell membrane, which is specifically bonded to mouse IL-6, and determined the primary structure thereof (see Japanese Patent Application No. 1-292230). Furthermore, the inventors prepared a soluble IL-6 receptor (extracellular portion of an IL-6 receptor), considered to be usable for a therapeutic or diagnostic medicine, from the human IL-6 receptor gene as the starting material (see Japanese Patent Application No. 1-9774).

SUMMARY OF THE INVENTION An artificial control of the function of IL-6 strongly exerting physiological activities in a organism ie considered usable as a new mechanism for the therapy of various diseases, and knowledge of the course of the transmission of an IL-6 signal is important in the development of a medicinal substance for enhancing or inhibiting the function of IL-6.

The inventors investigated the mechanism of the transmission or 11.-0 signal, ana as a result, rouna that, in addition to the IL-6 and IL-6 receptor, there exists, as a third factor, a protein participating in the transmission of IL-6 signal. Since this protein has an apparent molecular weight of 130 kb, the inventors named thia protein human gpi30. To further analyze the transmission of IL-6 signal or to develop a soluble gpl30 (the extracellular portion of a gpl30 protein) as an inhibitor for IL-6, a large quantity of a purified product of soluble gpl30 must be obtained but the amount of gpl30 produced in an organism is very small. A DNA sequence coding for pgl30 is indispensable for producing gpl30 in a large quantity by a genetic engineering method.

Therefore, a primary object of the present invention is to provide a human gpl30, a DNA coding for the gpl30, and a process for producing the gpl30 by using the DNA.

The inventors carried out research into the transmission of IL-6 signal, and found a protein on the cell membrane which participates in the transmission of IL-6 signal, and furthermore, proved that the IL-6 receptor on the cell membrane is bonded to this membrane prntaln through tha bonding to TT.-fi, this mambrana protein bears the transmission of IL-6 signal, and the intracellular region of the IL-6 receptor does not participate in the transmission of IL-6 signal.

Also, the inventors succeeded in cloning a DNA coding for human gpl30, and determined the nucleotide sequence of this DNA.

The present invention is based on the results of these researches. More specifically, the present invention provides a gpl30 participating in the transmission of IL-6 signal; a DNA sequence coding human gpl30; a replicable vector capable of expressing this DNA sequence in a recombination microorganism or cultured cell; a microorganism or cultured cell transformed by this expression vector; and a process for the production Of human gpl30, which comprises expressing a DNA sequence coding gpl30 in this microorganism or cultured cell.

BRIEF DESCRIPTION OP THE DRAWINGS ' ‘ Figure 1 shows autoradiographic patterns obtained when U266 cells internally labollod with 35S-methionine are lysed after treatment with IL-6 (lanes 2 and 4) or without treatment with IL-6 (lanes 1 and 3), and then immunoprecipitated by an IL-6 receptor antibody MT18 immobilized on Sepharose B4, and SDS/PAGB is carried out under non-reducing conditions (lanes 1 and 2) or under reducing conditions (lanes 3 and 4); Fig. 2 shows autoradiographic patterns obtained 125 when M12IL6R cells surface-labelled with I are lysed after treatment with IL-6 (lane 2) or without treatment with IL-6 (lane 1), and is then treated in the same manner as in Fig. 1; Fig. 3 shows autoradiographic patterns obtained when M12 cells are incubated in the presence (lanes 2 and 4) or absence (lanes 1 and 3) of IL-6 and in the presence of a culture supernatant of COS7 cells containing soluble IL-6 receptor (lanes 3 and 4) or not containing soluble IL-6 receptor (lanes 1 and 2) and lysed, and is then treated in the same manner as in Fig. 1; Fig. 4 shows incorporation of 3H-labelled thymidine by MI cells in the presence of IL-6 at various concent rat 1nns, and jn the presence or absence of a soluble IL-6 receptor; Fig. 5 shows a restriction enzyme map of AA and AB and a schematic structure of a corresponding human gpl30 protein, in which E represent· the EcoRI site, $5 represents the signal sequence, EC represents the extracellular region, TM represents the membrane penetration region, and C represents the intracellular region; Fig. 6 shows the structure of pGP130; Figs. 7-1 through 7-6 show the results of the analysis of the nucleotide sequence of insert DNA of PGP130, i-e., DNA coding for human gpl30, and show the presumed amino acid sequence of a protein, i.e., human gpl30 produced when this DNA sequence is expressed, in which the underlined portion represents a hydrophobic euuinu acid region on the N-terminal side and the double-underlined portion represents a hydrophobic amino acid region on the C-terminal side; and.

Fig. 8 shows the results of a Northern blot analysis of various cells conducted by using human gpl30 cDNA as the probe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 1. gp!30 Protein The cell membrane-derived protein participating in the transmission of IL-6 signal according to the present invention, i.e., gpl30, exerts an important function when IL-6 ie bonded to an IL-6 receptor to finally cause various cells to exert biological activities such as proliferation and differentiation, and in the natural state, this protein is located on the cell membrane. The IL-6 referred to herein includes IL-6 produced in an organism, IL-6 produced by a genetic engineering method, and derivatives thereof.

Furthermore, the IL-6 receptor includes a IL-6 receptor present on the cell membrane produced in an organism or by a genetic engineering method, a soluble IL-6 receptor isolated from the cell membrane, and derivatives thereof.

Thie protein has the following properties. (1) The protein is bonded to a complex of s IL-5 and an IL-5 receptor. (2) The protein ie not bonded to IL-6 alone or IL-6 receptor alone. (3) The protein shows an apparent molecular 5 weight of 130 kDa in the SDS-polyacrylamide gel electrophoresis. This protein participates in the transmission of IL-β signal and in the natural state, has an amino acid sequence of from Met at 1-site to Gin at 918-site in Fig. 7. In the present invention, the 0 protein may be any protoin having the above-mentioned amino acid sequence, and a protein or ptiiypeptide having a portion of the above-mentioned amino acid sequence that makes a contribution to the specific bonding to a complex of IL-6 and IL-6 receptor. Namely, all proteins and polypeptides having an amino acid sequence in which at least one amino acid residue of the above-mentioned amino acid sequence is substituted by another amino acid residue(s), or at. least on amino acid sequence is deleted from the above-mentioned amino acid sequence, or at least one amino acid is added to the above-mentioned amino acid sequence, and still retaining a capacity of being specifically bonded to complex of IL-6 and IL-6 receptor, are included within the scope of the pgl30 of the present invention. For example, there can be mentioned proteins in which an amino acid sequence or amino acid residue not making a contribution to the bonding to the complex of IL-b and IL-6 receptor in the above-mentioned amino acid sequence is modified by substitution, deficiency or insertion, proteins in which an amino acid sequence and/or an amino acid residue portion is added to the N-terminal side and/or the C-terminal side of the above-mentioned amino acid sequence, and proteins formed by a fusion of another protein, such as a human growth hormone, to the above-mentioned amino acid sequence.

The amino acid sequence represented by formula (I) consists of 918 amino acid residues, and hydrophobic •Ε 902930 amino residues are located in the region of from leucine at the second position from the N-terminal side to glycine located at the 22nd position and the region of from alanine at the 620th position to phenylalanine at the 641st position. It is considered that, of these two regions, the former region is a signal peptide region and the latter region is a membrane penetration region. 2. DNA Sequence DNA coding for human gpl30 protein of the 1θ present invention encodes, for example, an amino acid sequence of from Met at 1-position to Gin at 9l8poeition in Fig. 7. Representative cDNA has a base sequence of from A at 273-position to G at 3026-position in Fig. 7. The DNA sequence of the present invention includes not only the above-mentioned DNA sequence but also DNA in which at least one nucleotide of the above-mentioned DNA sequence is substituted with another nucleotide, or at least one nucleotide is deleted from the above-mentioned DNA sequence, or at least one nucleotide is added to the above-mentioned DNA sequence, and which codes for a protein having a capacity of being specifically bonded to the IL-6/IL-6 receptor complex.

For example, there can be mentioned DNA sequences coding proteins having the amino acid sequences as mentioned in (1) above. 3. Process for Preparation of gpl30 Protein According to the first process of the present invention, the cell membrane-derived protein participating in the transmission of IL-6 signal is prepared from animal cell· producing this protein. As the cells, there can be mentioned IL-6 receptor-producing cells, for example, human myeloma cell U266, mouse leukemia cell line Ml, and human B cell line CL4. The protein of the present invention participating in the transmission of IL-6 signal also can be produced by cells not producing IL-S receptor. As the cells of this type, mouse S cell line M12, human T cell line Jurkat, and IE 902930 - ’ mouse T cell line CTLL2 can be mentioned. Namely, the protein participating in the transmission of IL-6 signal according to the present invention can be obtained from these cells.

S As pointed out hereinbefore, the protein of the present invention is bonded to the IL-6 receptor in the presence of IL-6 but is not bonded to the IL-6 receptor in the absence of IL-6, and therefore, the protein of the present invention can be isolated by utilizing thia property.

For example, to isolate the protein from cells producing both the IL-6 receptor and the protein of the present invention, a process can be adopted in which the producing cells are cultured, IL-6 is artificially added to the cultured cells, incubation is carried out for a time sufficient to allow a reaction between the cells and the Adrtprf TT.-6 under physiological conditions, for example, for about 30 minutes at about 37°C in a conventional culture medium such as RPMI1640, and the cells are then lysed by a customary method, for example, by a treatment with a triethanolamine buffer solution containing 1% of digitonine, whereby a cell lysate containing a complex in which IL-6, the IL-6 receptor and the protein of the present invention are bonded together is obtained. Alternatively, after the cells are lysed by a customary method, incubation is carried out in the above-mentioned manner to obtain a cell lysate containing the above-mentioned complex. An antibody to IL-6 receptor, for example, MT18 antibody (prepared according to Referential Example 1 given hereinafter; see Japanese Patent Application No. 63-194885) is immobilized by a solid carrier, for example, Sepharose 4B, by the cyanogen bromide activation method. By placing this immobilized antibody to IL-6 receptor in contact with the above-mentioned cell lyeate, the complex containing the protein of the present invention is immobilized on the above-mentioned solid carrier through th· specific reaction between the IL-6 receptor and the IL-6 receptor antibody. Then, this solid Carrier is washed to remove non-specifically bonded or adhering impurities, and the complex is eluted from the solid carrier by a conventional means using, for example, urea or guanidine, to free the desired protein of the present invention from the IL-6 receptor-containing protein complex.

To isolate and purify the desired protein of 10 the present invention from the obtained solution, customary means adopted for the isolation and purification of proteins, such as precipitation using ammonium sulfate, column chromatography, for example, reversed phase chromatography and ion exchange chromatography, and electrophoresis can be used. During this isolation and purification process, an active fraction can be selected by utilizing the bonding to the IL-6 receptor in the presence of IL-6, non-bonding to the IL-6 receptor in the absence of IL-6, and confirming the molecular weight of 130 kDa as the critorion.

Where cells producing the protein of the present invention but not producing the IL-6 receptor are used, incubation is carried out in the presence of a soluble IL-6 receptor and IL-6, and the cells are then lysed to obtain a cell lysate containing an IL-6/IL-6 receptor/desired protein complex. Alternatively, the above-mentioned cells producing the protein of the present invention are lysed, an incubation of IL-6 and the IL-6 receptor is carried out, arid finally, a cell lysate containing an IL-6/IL-6 receptor/desired protein complex is obtained. The desired protein can be isolated and purified from this cell lysate in the above-mentioned manner.

The second process for the production of the protein participating in the transmission of IL-6 signal according to the present invention utilizes gene recombination. In this process, DNA coding for an amino - 9 acid sequence of a protein on the cell membrane, which participates in the transmission of IL-6 signal, can be obtained by various methods. For example, cDNA library is formed from cells expressing the above-mentioned protein thereon, such as human myeloma cells, according to customary procedures, and this library is selected according to various methods, for example, the method in which a probe designed on the basis of a partial amino acid sequence of the purified protein is used, and the method in which cDNA is expressed and the selection is made based on the property of the produced protein, for example, the specific bonding to the lL-6-bonded IL-6 receptor. The protein of the present invention is produced by expressing the thus-cloned DNA according to customary procedures. 4. DNA Coding gpl30 Protein The DNA to be used for the above-mentioned process can be prepared based on desired messenger RNA selected from various messenger RNA's extracted, for example, from the human placenta by a known method, by using a probe prepared based on the DNA sequence of Fig. 7 provided by the present invention.

Alternatively, a part or all of this DNA can be chomioally oynthooinod according fee the disclosure of the present invention.

. Expression Vector As the replicable expression vector capable of expressing the DNA sequence coding human gpl30 provided according to the present invention, any vector having a replicating origin, control sequences and a sequence coding for gpl30, and capable of transforming a selected host can be appropriately used without limitation. For example, plasmids such as pBR322 and pBR327 oan be used when E, coll is used as the host, and when cultured cells of a mammal or the like is used as the host, a vector having a DNA replicating origin derived from SV40 virus, can be used.

Of the control seguencee for expressing the coding sequence, promoter system ie important, and an appropriate promoter eyetem should be elected according to the relationship to the selected host, when E, coll is used as the host, lactose promoter system, a tryptophan promoter system and hybrid promoter systems thereof are preferably selected. When cultured cells derived from a mammal are used as the host, an SV40 promoter system* adenovirus promoter system, and cytomegalovirus promoter system are preferably selected. 6. Host Microorganisms or cultured cells customarily ueed for producing proteins by genetic engineering can be used as the host without limitation. As the microorganism, there can be mentioned E, coli such as K-12 or W-3110, Bacillus subtilis and yeast, and as the cultured cells, there can be mentioned COS cells (monkey renal fibroblast), CHO cells (Chinese hamster oocyte), and myeloma cells.

The host explained in (4) above, which has been transformed by the vector explained in (5) above, is cultured to express the DNA sequence coding for human gpl30 in the vector DNA, whereby human gpl30 is produced. This is realized by the activation of the promoter system in the control sequences linked to the DNA sequence coding for human gpl30.

A polyclonal antibody or monoclonal antibody to the protein of the present invention can be prepared according to customary procedures by using the protein of the present invention prepared according to various processes as described above, or the cell producing this protein as an immunogen. As the cell source and animal to be used in this preparation process, there can be mentioned organisms such as human, mouse, rabbit, goat, end sheep.

The cell membrane-derived protein participating in the transmission of IL-6 signal, provided η according to the present invention, can be used as a reagent for clarifying the signal transmission mechanism of IL-6 and developing valuable substances such as therapentic agents for controlling the function of Il-6.

For example, by using, as a detection criterion, the property of the present protein which transmits IL-6 Rlgnnl while being specifically bonded to tho IL-6 receptor bonded to IL-6, substances controlling the function of IL-6 can be screened. As the substances to be screened, there can be mentioned natural substances, synthetic chemicals, IL-6 and an IL-6 receptor produced by a genetic engineering, derivatives thereof, and antibodies to IL-6, the IL-6 receptor, and antibodies to these proteins.

Furthermore, by bonding the soluble IL-6 receptor which has been bonded to IL-6 to the present protein, the function of IL-6 can be enhanced, and the function of IL-6 can be exerted even on a cell having no IL-6 receptor in the cell surface layer. On the other hand, if the bonding of the above-mentioned protein to the IL-6 receptor which has been bonded to IL-6 is inhibited by an antibody to IL-6, IL-6 receptor or the above-mentioned protein, the biological activity of IL-6 will be inhibited- Accordingly, it is considered that Ui* protein of the present invention will be usable as an active ingredient of a medicine.

Furthermore, by the DNA sequence coding for human gpl30 according to the present invention, and the means and process for producing this protein by genetic engineering, thi* protein, which is produced only in a very small amount in the natural state, can be produced in a large quantity.

The present invention will now be described in detail with roforonco to the following examples, that by no means limit the scope of the invention. Note, the protein of the present invention is sometimes called gp!30 in the examples for convenience.

Example 1 Bonding of Protein (Qp130) on Human Cell Membrane to Human IL-6 Receptor In Presence of Human IL-6 Human myeloma cells U266 (cells producing the IL-6 receptor and gp!30 protein) (2 x 10 cells) were 35 internally labelled with 1 mCi of S-methionine and divided into two parts. One part was Incubated in 0.5 ml of PRMH640 at 37®C for 30 minutes in the presence of IL-6 (1 pg/ml), and the other part was similarly incubated in the absence of IL-6. Then, the U266 cells were lysed with 1 ml of a 10’mM triethanolamine buffer solution (having a pH value of 7.4) containing 1% of digitonine (supplied by Wako Junyaku), 0.15 M NaCl, and 1 mM pAPMSF (supplied by Wako Junyaku). Separately, the IL-6 receptor antibody MT18 (Referential Example 1) was bonded to Sepharose 4B activated by cyanogen bromide, and the bonded antibody then mixed with the supernatant of the above-mentioned cell lysate, whereby the solubilized IL-6 receptor was bonded to the MT18 antibody on the resin.

The non-specifically bonded substances were washed away by the above-mentioned solution containing 1% of digitonine. Then, under reducing or non-reducing conditions, the polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS/PAGE) and the autoradiography were carried out. The results are shown in Fig. 1. In Fig. 1, the band of 80 kDa shows the 33s-methionine-labelled IL-6 receptor derived from the U266 cell, and the band of 130 kDa shows the gpl30 protein of the present invention. From the results shown in Fig. 1, it is seen that the IL-6 receptor bonded to il-6 is bonded to the human protein (gp!30) having a monomer molecular weight of 130 kDa within 30 minutes at 37eC. g7t?PP4tt. 2 Bonding of Human IL-6 receptor .to Protein (qplW on Mouse Cell Membrane in Presence of Human IL-6 A plasmid prepared by inserting a human IL-6 receptor cDNA into the site of BamHI in the plasmid pZipNeoSV(X)l (see Cepko et al, Cell, 37, page 1053, 1984) was introduced into a mouse B cell strain M12 not expressing the IL-6 receptor on the cell surface, by the electropolation method, and the transformed cell was screened based on the resistance to an antibiotic oubotanoo C410 (supplied b'j» Tha thuoootabliohed mouse D cell Ml2-derived ulunu expressing the human IL-6 receptor on the cell surface wae named M12IL6R.

Then, 107 of M121L6R cells were washed with PBS and suspended in 0.1 ml of 50 mM Tris (having a pH value of 12S 7.4) and 0.15 M NaCl. Next, 1 mCi of Na PI and two 15 Iodobeads (supplied by Pierce) were reacted at room temperature for 5 minutes in 0.1 ml of the abovementioned buffer solution, the reaction liquid was mixed with the above-mentioned cell suspension, and incubation was carried out at room temperature for 30 minutes.

Then 1 /ig/ml of IL-6 was added to the thus-labelled cells, or was not added, and the reaction was carried out at 37eC for 30 minutes, the cell was lysed according to the method described in Example 1, an immunoprecipitation by MT18 was carried out, and the SDS/PAGE and autoradiography were then carried out. The results are shown In Fig. 2. In Fig. 2, the band of 80 kDa shows the IL-6 receptor produced by the IL-6 receptor cDNA introduced into an M12 cell, and the band of 130 kDa shows a gpl30 protein inherently produced by the M12 cell. From the results shown in Fig. 2, it is seen that the human IL-6 receptor on M12IL6R bonded to the human IL-6 is bonded to the mouse protein (gpl30) derived from M12IL6R, at 37®C within 30 minutes.

Example.,! Bonding of Soluble, IL-6 Receptor to qp!30 ln Presence of IL-6 According to the method described in Example 2, χ 10 of Ml2 cells (cells not producing IL-6 receptor) were labelled, 5 χ 10^ of the labelled cells were added to 1 ml of a culture supernatant of COS7 cells containing or not containing the soluble IL-6 receptor in the presence or presence of IL-6 (1 /*g/ml), and the reaction was carried out at 37°C for 30 minutes. Then the cells were lysed with digitonine according to the method described in Example 1, immunoprecipitation was carried out by MT18 antibody, and the SDS/PAGE and autoradiography were then carried out. The results are shown in Fig. 3. In Fig. 3* the band of 130 kDa shows the gpl30 protein produced by M12 cells. Note, in this example, since the soluble IL-6 receptor was not labelled, this receptor was not shown by the autoradiography. From the results shown in Fig. 3, it is seen that the complex of IL-6 and the soluble IL-6 receptor is bonded to the protein (gpl30) on the cell membrane, and the soluble IL-6 receptor alone is not bonded to gpl30.

Example 4 Enhancement of Function of IL-6 bv Soluble IL-6 Receptor in Presenceof IL-6 Ml cells (1 χ 105 cells/ml) were cultured at 0.2 ml/well in a culture medium containing IL-6 at various concentration as well as COS7 cell supernatant or soluble IL-6 receptor-containing COS7 cell supernatant in an amount of 25%. Within 60 to 70 hours from the start of the culturing, ^H-labslled thymidine was added, and by measuring the radioactivity incorporated into the cells, the proliferation of the cells was examined. Figure 4 shows that the effect of inhibiting the proliferation of Ml cells, possessed by IL-6, is enhanced by the soluble IL-6 receptor. Namely, the function of IL-6 is enhanced by the bonding of the IL-6-bonded soluble IL-6 receptor to gpl30 of Ml cell.

Isolation of Human qp130 cDNA A series of gen· recombination operations (extraction of m-RNA, cleavage of DNA by restriction enzyme, and the like) were carried according to the process of Maniatis et al (see Molecular Cloning, Cold Spring Harbor Laboratory, 1982) and the process of Harwin et al (see DNA Cloning, λ Practical Approach, vol. 1, page 49, IRL, Oxford, 1985). Screening by the antibody of Agtll cDNA library was carried out according to the conventional method.

First, a messenger (m) RNA was extracted from human myeloma call 11266 (see Cell, volume 58; page 573, 1989), and a cDNA library was prepared by using Agtll (supplied by Clontech). Then, using mouse-derived monoclonal antibodies AM64 and AM277 (see Japanese Patent Application No. 2-15090) to gpl30, about 500,000 clones were screened, and finally, two coulones (>A and Λ&) were obtained. The insert cDNA of each of >A and ab was analyzed, and the results are shown in Fig. 5. As shown in Fig. 5, the insert cDNAs did not contain the full length human gpl30-coding region.

Accordingly, an EcoRI fragment of AA and the EcoRI fragment of A^ were inserted, while connecting them in the orientation of reading of cDNA, to the EcoRI site of a vector pBlueScript SX (supplied by Stratagene) to prepare a plasmid pGPl30 having an insert DNA containing the complete human gpl30-coding region. The structure of pGP130 is shown in Fig. 6, and the sequence of the insert DVA of pGP!30, i.e., the sequence of human gpl30 cDNA determined from insert cDNA sequences of λΑ and Αβ , and the presumed amino acid sequence, are shown in Fig. 7.

Note, E, coli HBl0l/pGP130 containing this plasmid pGP130 was internationally deposited as deposition No. FERM BP-2912 under the Budapest Treaty on May 15, 1990 with the Fermentation Research Institute, Agency of Industrial Science and Technology, located at 1-3, Higashi l-Chome, Tsujuka~shi, Ibaragi-ken, Japan. gXSflple 6 Expression of Human gp!30 mRNA in-Varlous Cells To examine the expression of human gpl30 in various cells, Northern blot analysis was carried out. The culturing of cells, extraction of mRNA from the cells, electrophoresis, blotting, probe labelling, hybridization, filter washing, and autoradiography were carried out according to standard methods, mRNA was extracted from human myeloma cells U266, human B cells CESS, human Burkitt's lymphoma Jijoye, human T cells Jurkat, and NX cells YT,’and 1 μg of each mRNA then denaturated by the formamide method and subjected to electrophoresis with 0.8% agarose gel, and to Northern blotting on a nylon filter membrane. Then an insert cDNA of Αχ obtained by the method described in Example 5 was extracted, and using this extracted insert cDNA, hybridization was carried out at 42’C for 24 hours. The product was then washed and autoradiography was carried out.

The results are shown in Fig. 8, and it is seen that the manifestation of gpl30 mRNA is strong in U266 and YT, medium in CESS, and weak in Jijoye and jurkat. Thio hao a relation to the reactivity of the IL-6 uf each cell.

Referential,Example 1 Preparation of Monoclonal Antibody to Human IL-6 To prepare a mouse monoclonal antibody to human IL-6 receptor, a mouse T cells having human IL-6 receptors expressed on the cell membrane surface was prepared as an antigen, according to the following method. More specifically, pBSF2R.236 and pSV2neo disclosed in Japanese Patent Application No. 1-9744 woro introduced in mouse T-eelle CTLL-2 (ATCC, TIB214) according to a customary procedure, and screening was carried out according to the conventional method using G-418. Finally, the strain in which about 30,000 IL-6 receptors per cell were expressed was established, and this strain was named CTBC2.

The immunization was carried out in the following manner. The CTBC2 cells were cultured according to a conventional method using PRMI1640, and the cultured CTBC cells were washed four times with a PBS buffer and used intraperitoneally to immunize C57BL6 mouse in an amount of 1 x 10? cells per mouse once a week, six times as a whole.

The spleen cells of the immunized mouse were fused to the myeloma cells P3U1 oo tho parent eell line, according to a conventional method using polyethylene glycol.

Screening was carried out in the following manner.

Namely, pBRP2R,236 and PSV2neo were introduced into the IL-6 receptor-negative human T cell strain JURXAT (ATCC, CRL8163) according to a conventional method, and by the screening, a strain expressing about 100,000 IL-6 receptors per cell was established, and this stain was named ''NJBCe. One clone of the hybridoma producing an antibody recognizing NJBC8 lysed by NP40 but not recognizing JURXAT lysed by NP40 was isolated and named MT18. The monoclonal antibody produced by this hybridoma was named MT18 antibody.

Claims (14)

1. Human gpl30 protein having at least the following properties: (1) the protein has an affinity with a complex of IL-6 (interleukin-6) and an IL-6 receptor 5 (interleukin-6 receptor);

2. (2) the protein shows an apparent molecular weight of 130 kDa in SDS-polyacrylamide electrophoresis; and (3) the protein participates in the 10 transmission of IL-6 signal.

2. Human gpl30 protein as set forth in claim 1, which has an amino acid sequence from Met at the 1st site to Gin at the 918th position in Fig. 7.

3. DNA coding for human gpl30 protein as set 1 5 forth in claim l.

4. DNA as set forth in claim 3, which codes for a human gpl30 protein having an amino acid sequence of from Met at the 1st position to Gin at the 918th position in Fig. 7. 20

5. DNA as set forth in claim 4, which has a nucleotide sequence from A at the 273rd position to G at the 3026th position.

6. An expression vector containing DNA as set forth in claim 3 and capable of expressing said DNA in a 25 hoet cell.

7. A process for the production of human gpl30 protein, which comprises culturing host cells transformed by an expression vector as set forth in claim 6. 30 8.

Human gpl30 protein substantially free of another human protein, which is produced by using DNA as set forth in claim 3. -199.

A human gpl30 protein according to claim 1, substantially as hereinbefore described and exemplified.

10. DNA according to claim 2, substantially as hereinbefore described and exemplified.

11. DNA according to claim 2, substantially as hereinbefore described with particular reference to and as illustrated in the accompanying drawings.

12. An expression vector according to claim 11, substantially as hereinbefore described and exemplified.

13. A process for the production of a human gpl30 protein according to claim 1, substantially as hereinbefore described and exemplified.

14. A human gpl30 protein according to claim 1, whenever produced by a process claimed in a preceding claim. Dated this the 13th day of August, 1990 F. R..KELLY & CO. BY /j EXECUTIVE 27 Clyde Road, Ballsbridge, Dublin 4 AGENTS FOR THE APPLICANTS