DNA coding for human cell surface antigen

Abstract

DNAs coding for human cell surface antigen (Fas or Fas antigen), vectors for expressing for said DNAs and transformants transfected with said vector are proveded. Fas is a polypeptide that exists in the surfaces of a variety of cells and is considered to be deeply concerned with the apoptosis of cells.The isolated Fas CDNA has an open reading frame that is capable of encoding a protein consisting of 335 amino acids. The mature Fas antigen is a protein consisting of 319 amino acids having a calculated molecular weight of about 36,000 and is constituted by an extracellular domain of 157 amino acids, a membrane-spanning domain of 17 amino acids, and a cytoplasmic domain of 145 amino acids.

Description

FIELD OF THE INVENTION

The present invention relates to DNAs coding for human cell surface antigen (hereinafter referred to as Fas or Fas antigen) and to vectors for expressing for said DNAs.

BACKGROUND OF THE INVENTION

Fas is a polypeptide that exists in the surfaces of a variety of cells and is considered to be deeply concerned with the apoptosis of cells. The apoptosis is a form of death of cells that is distinguished from the so-called necrosis of cells, and is observed at the time of death of various cells such as of embryogenesis, metamorphosis, endocrine-dependent tissue atrophy and turnover of normal tissues [Wyllie et al. Int. Rev. Cytol. 68, 251-306, 1980; Walker et al. Meth. Achiev. Exp. Pathol. 13, 18-54, 1988; Schmidt et al. Proc. Natl. Acad. Sci. USA 83, 1881-1885, 1986; Ucker et al. Nature 327, 62-64, 1987; Smith et al. Nature 337, 181-184, 1989, Williams et al. Nature 343, 76-79, 1990].

The following features have been pointed out as a result of the morphological and biochemical analyses of cells at the apoptosis:

The apoptosis is accompanied by condensation of cytoplasm, loss of plasma membrane microvilli, segmentation of the nucleus, extensive degradation of chromosomal DNA (into oligomers of about 180 base pair units), and formation of apoptotic bleb [Wyllie et al. 1980 (mentioned above)]. The apoptosis is a physiologically and medically interesting phenomenon because it is a form associated with the death of immunocytes such as thymocytes and the extinction of the tumor cells.

In regression of tumor (alleviation of tumor), in general, the apoptosis mediates the death of target cells by interaction with natural killer cells or cytotoxic T lymphocytes [Duke et al. Proc. Natil. Acad. Sci. USA 80, 6361-6365, 1983; Schmidt et al, 1986 ibid.; Ucker, 1987 (mentioned above)], or by tumor necrosis factor-α (TNF-α) or its related cytokine lymphotoxin (TNF-β) against the target cells [Schmidt et al, 1986 (mentioned above); Dealtry et al. Eur. J. Immunol. 17, 689-693, 1987; Larrick and Wright, FASEB J. 4, 3215-3223, 1990].

With regard to the relationship between the Fas antigen and the apoptosis, the present inventors have previously disclosed that the mouse monoclonal antibody against the human Fas antigen has a cytolytic activity on human cells expressing the Fas antigen while it does not act upon mouse cells [Yonehara et al. J. Exp. Med. 169, 1747-1756, 1989]. It has also been disclosed by Trauth et al. that the anti-Apo-I antibody has effects analogous to those of the anti-Fas antibody [Science 245, 301-305, 1989].

In a recent study by the present inventors, furthermore, it has been found that cells infected with human immunodeficiecy virus (HIV) are more sensitive to the cytocidal activity of the anti-Fas monoclonal antibody than uninfected cells [Kobayashi et al. Proc. Natl. Acad. Sci. USA 87, 9620-9624, 1990]. However, it is still not clear whether the expression of the Fas antigen that is predominant in the infected cells is actually induced by infection with HIV or by a general transformation.

It is also considered potential to specifically drive the HIV- infected cells into apoptosis by using a monoclonal antibody specific to Fas antigen.

The present inventors have further discovered that the. treatment of human colon carcinoma HT-29 cells with interferon-γ (INF-γ) induces the Fas antigen on the cell surface, and renders the tumor cells more susceptible to the cytotoxic activity of the anti-Fas antibody (Yonehara et al, J. Exp. Med., 169: 1747-1756, 1989).

As described above, it has been pointed out that the Fas antigen is closely related to the apoptosis but numerous points remain not clarified. Therefore, it is physiologically and pathologically meaningful to disclose the entire structure of the Fas antigen and to clarify its function. It is further considered that various monoclonal antibodies that specifically reacts with Fas may be easily obtained if the structure of the Fas antigen is disclosed, and used in treating diseases associated with HIV infection and malignant tumors to be cured.

Therefore, it is physiologically and pathologically very advantageous to clarify the main body of Fas antigen, to clarify its complete structure and to clarify its function. Furthermore, if the Fas antigen is obtained in large amounts in pure form, it will become possible to more clearly analyze its structure and functions. By utilizing the knowledge related to the thus clarified structure of Fas antigen, it will still become possible to study the Fas antigen analogs by modifying them as well as to utilize in large amounts only those portions essential to the expression of the functions.

With the structure of the Fas antigen being clarified, furthermore, it will become possible to obtain various monoclonal antibodies that specifically reacts with Fas as well as to obtain various ligands, agonists and antagonists related to Pas, and to develop studies with regard to their effects upon the cells and relationships of the structure and activities thereof.

In order to accomplish the above object, it is essential to establish means capable of supplying Fas polypeptides in sufficient amounts. In recent years, a recombinant DNA technology has been utilized as a method for preparing physiologically active substance. In order to prepare the Fas antigen by utilizing the above technology, however, it is necessary to isolate DNA that encodes Fas proteins followed by cloning.

SUMMARY OF THE INVENTION

The present inventors have succeeded in the development of means capable of producing in large amounts the human Fas antigen in pure form. The present inventors have clarified the genes of the human Fas antigen and have disclosed, for the first time, how to genetically manipulate the Fas antigen genes.

The present invention provides DNA coding for human Fas antigens, DNA derived therefrom, and DNA fragments thereof. They may include those having an anti-sense sequence thereof. The present invention further provides products such as proteins and peptides produced by using the DNA that encodes the Fas antigen or by using derivatives thereof.

The invention also provides plasmids or vectors that carry DNA coding for the Fas antigen or DNA derived therefrom or fragments thereof. Moreover, the invention provides a variety of transformants that hold replicably or expressibly the plasmid or the vector therein. The present invention encompasses a variety of products produced by utilizing base sequence information of DNA encoding the Fas antigen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the nucleotide sequence and predicted amino acid sequence of the cDNA coding human Fas protein (up to 284th amino acid)(SEQ ID NO: 1 and SEQ ID NO: 2).

FIG. 2 shows the nucleotide sequence and predicted amino acid sequence of the cDNA coding human Fas protein (after 284th amino acid) (SEQ ID NO: 1 and SEQ ID NO: 2).

FIG. 3A shows the schematic representation and restriction map of the human Fas cDNA (pF58).

FIG. 3B shows the hydropathy plot of amino acid sequence of human Fas antigen.

FIGS. 4A-F shows the graph representing the results examined by a flow fluorometry for the expression of the human Fas antigen in mouse cells transformed with the human Fas expression vector. Expression plasmid pEFF-58 and a plasmid carrying the neo-resistance gene were cotransfected into WR19L cells or L929 cells and selection was conducted in the presence of G-418 to give several G-418-resistant clones. Then, parental WR19L and L929 cells, 2 transformants derived from WR19L (58-12a and 58-80d) and 2 clones derived from L929 (LB1 and LB11) were stained with anti-Fas antibody (IgM) and anti-mouse IgM antibody bound with FITC, followed by subjecting to flow cytofluorometry. FIGS. 4A- 4F represent WR19L, 58-12a, 58-80d, L929, LB1, and LB11, respectively.

FIG. 5 shows the graph representing cytolytic effect of the anti-Fas antibody on the WR19L transformant clones.

FIG. 6 shows the graph representing cytolytic effect of the anti-Fas antibody on the L929 transformant clones.

FIG. 7 shows the schematic representation of comparison in amino acid sequence of Fas antigen with other members of the NGFR/TNFR family.

FIG. 8 shows the schematic representation of comparison in amino acid sequence of extracellular domain of the human Fas with other members of the NGFR/TNFR family. (hFAS=SEQ ID NO: 3, hTNFR1=SEQ ID NO: 4, hTNFR2=SEQ ID NO: 5, hNGFR=SEQ ID NO: 6, hCD40=SEQ ID NO: 7, rOX40=SEQ ID NO: 8)

FIG. 9 shows the comparative representation of the amino acid sequences of the cytoplasmic domains of the Fas (SEQ ID NO: 10), TNF (SEQ ID NO: 11) receptor type I and CD 40 (SEQ ID NO: 9).

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to DNA coding for human cell surface antigen or those having substantially the same functions as said human cell surface antigen, DNA derived therefrom or DNA fragmented therefrom. Particularly, the invention relates to DNA coding for Fas antigens, preferably peptides having at least a part of the amino acid sequences, and more preferably the amino acid sequences described in FIGS. 1 and 2 , which are identified in the Sequence Listing as SEQ ID NO:1 and SEQ ID NO:2.

Furthermore, the invention relates to DNA comprising at least a part of the base sequences described in FIGS. 1 and 2 , which are identified in the Sequence Listing as SEQ ID NO:1 and SEQ ID NO:2, preferably DNA having the base numbers 195 to 1199, 243 to 1199, 195 to 713 or 243 to 713 of FIGS. 1 and 2, or a portion thereof.

The invention still relates to proteins or peptides comprising at least a part of the amino acid sequences having a substantially human cell surface antigen activity, particularly a Fas antigen activity, preferably at least a part of the amino acid sequences described in FIGS. 1 and 2 , and more preferably the amino acid numbers −16 to 319, 1 to 319, −16 to 157, or 1 to 157 described in FIGS. 1 and 2 , which are identified in the Sequence Listing as SEQ ID NO:1 and SEQ ID NO:2.

The invention also relates to expression vectors comprising the above DNA, transformants transformed by said expression vector and methods for producing said protein or peptide which comprises cultivating said transformant under a suitable condition in a suitable medium and collecting the produced protein or peptide from the cultured medium.

The present invention is also concerned with various reagents for analysis or medical drugs comprising an effective amount of the product such as proteins obtained as described above as well as antigens obtained as described above.

According to the present invention, it would become possible to develop Fas genes or Fas gene analogs in various cells inclusive of human cells by utilizing information related to base sequences of the cDNA clone (for example, pF85) or fragments derived therefrom or base sequences thereof.

It should be comprehended that the present invention is concerned with those that are thus finally obtained. The development can be effected according to methods described in this specification or according to suitably modified methods.

The present inventors have screened a variety of human cell lines in connection with the expression of the Fas antigen and have discovered that human T cell lymphoma KT-3 expresses the Fas antigen about 20 times as much as other cell strains. The inventors have succeeded in isolating and cloning cDNAs encoding human Fas antigen determinant from human T cell lymphoma KT-3 cells.

FIGS. 1 and 2 show a cDNA nucleotide sequence and predicted amino acid sequence from a human Fas antigen cDNA clone (pF 58) that is obtained herein.

FIG. 3 shows a restriction map of cDNA (pF 58) for human Fas antigen.

The transformant ( Esherichia coli, pF 58) carrying the plasmid pF 58 was originally deposited as a domestic microorganism deposit (FERM P-12192) at the Fermentation Research Institute, Agency of Industrial Science and Technology, Ministry of International Trade and Industry, Japan (FRI) on Apr. 12, 1991 and converted into an international one (FERM BP-3826) under the Budapest Treaty.

The above pF58 cDNA has an open reading frame that is capable of encoding a protein consisting of 335 amino acids. From the predicted amino acid sequence, it is estimated that the mature Fas antigen is a protein consisting of 319 amino acids and is constituted by an extracellular domain, a transmembrane domain and a cytoplasmic domain. Such a constitution is common to many cell surface receptors. As will be described later, it was confirmed through the comparison of the amino acid sequence of the Fas protein with amino acid sequences of other cell surface proteins that the above Fas protein pertains to an NGFR/TNFR family in the group of cell surface membrane proteins.

A lot of cell surface receptors have heretofore been discovered, and targetting molecules including monoclonal antibodies against the receptor or various ligands related thereto or derivatives of the receptor or analogs thereof have been developed in the art. Furthermore, extensive investigations have been made on the development of methods for the treatment or diagnosis of deseases by using such products.

For instance, it has been known that CD4 which is a cell surface antigen of lymphocytes works as a receptor when the cells are infected with human immunodeficiency virus (HIV), AIDS virus. It has been reported by many researchers that the soluble mutant CD4 having a binding region to HIV, which is derived from natural CD4 by a genetic engineering based upon the above knowledge, may weaken the HIV infectivity or cytopathic effect

[Smith, D H. et al., Science 238: 1704-1707, 1987; Fisher, R A. et al., Nature 331: 76-78, 1988; Hussey R E. et al. Nature 331: 78-81, 1988; Deen, K C. et al. Nature 331: 82-84, 1988; Traunecker, A. et al.,. Nature 331: 84-86, 1988; Manca P. et al, Lancet 335: 811-815, 1990].

Furthermore, Olsson, I. et al. reports general thesis concerning the receptors of hematopoetic control factors [Eur. J. Haematol. 48: 1-9, 1992] in which they disclose that a variety of receptors exist in a soluble form in the living body. The TNF-binding protein found in urea is a soluble TNF receptor which exists on the cell surface and which is liberated from the cells by the action of a proteolytic enzyme. In the case of an M-CSF receptor, protein kinase C is activated, thereby the transmembrane domain of the receptor being cut and the soluble receptor consisting of an extracellular domain alone being emitted. There is a mRNA coding for the soluble proteins of IL-4 and IL-7 receptors in cells. It is confirmed that there is even a mRNA without the sequence coding for a transmembrane domain of the M-CSF in U-937 cells. Concerning the physiological meaning of the presence of such molecules in the living body, they have estimated that the soluble TNF receptor regulates the physiological activity of TNF that is emitted in vivo and suggested clinical applications such as application to endotoxinshock therapy in which it is becoming apparent that TNF strongly participates in the development of the disease.

A variety of discoveries have also been reported concerning the IL-2 receptor. For instance, according to Soulillou, J P. et al. [Transpl. Int. 2(1): 46-52, 1989], the monoclonal antibody that inhibits the bonding of IL-2 to IL-2 receptor is effective in controlling the rejection when the organs are transplanted. It is considered that such a monoclonal antibody is an antagonist against the IL-2 receptor in a broad sense. Rubin, LA. et al. reports that measurement of the concentration of soluble IL-2 receptors in the blood is effective in diagnosing or comprehending the condition of blood cancers, AIDS, rheumatic diseases, or various inflammations and infections [Anal. Intern. Med. 113: 619-627, 19903.

Concerning the IL-1 receptor, it has been reported that what is called natural IL-1 receptor antagonist exists in the living body [Arend, WP. et al., Br. J. Rheumatol. 30 suppl. 2:49-52, 1991]. Interestingly, this is a protein which exhibits immunological cross-reactivity with IL-1 and has been confirmed to suppress the activity of IL-] by competition with IL-1 on a receptor site. Thereafter, the analysis of the genes encoding the receptor antagonist has demonstrated that it is a distinct protein having a homology of only about 19 to 30% with respect to IL-1.

In recent years, furthermore, a cloned protein having a receptor-like structure has helped the clarification of the presence of ligand by using genetical alterations of the receptor-like protein and the disclosure that the ligand-receptor system regulates the propagation of hematopoetic stem cells. The function of the ligand-receptor system had not been known for long periods of years in the field of hematology. Since the expressed product of c-kit cloned as a cellular oncogene had the structure exhibiting a high degree of homology with respect to the cell surface receptor which had a tyrosine kinase active demain, the cloned c-kit had been estimated to be a receptor that transmits some ligand information in the living body. At a moment when c-kit was cloned, however, the ligand had not been known at all. Under such circumstances, Flanagan, J G. et al. has confirmed the presence of proteins that couple therewith by using genetically modified c-kit proteins. They further have clarified that the proteins having a binding property with c-kit are not expressed in the mouse-derived cells that have been known to genetically possess abnormality in the hematopoietic control system, and have reached a conclusion that they are the hematoblast growth factors and their receptors. The hematopoietic stem cell growth factors and their receptors which have not been known for many years until the disclosure. This discovery is very interesting in that the ligand was identified by using receptors that had been clarified previously.

In view of the fact that the Fas antigen protein of the present invention has the structure that serves as a cell surface receptor, it is clear that various ligands, agonists and antagonists specific or related to Fas antigen, can be developed on the basis of methods or ideas for investigating or reseaching the aforementioned numerous cell surface receptors and a variety of the corresponding molecules against the corresponding receptors such as soluble molecules, ligands and antagonists, or on the basis of methods which are basically the same as or resemble the knowledge obtained therefrom. Therefore, the thus obtained various acting substances such as ligands, agonists and antagonists are or may be encompassed within the scope of the present invention.

The cDNA (e.g. pF58) encoding the Fas antigen of the present invention is inserted into a plasmid for expression under the regulation of a human peptide chain elongation factor 1α gene promotor to construct an expression plasmid (e.g. pEFF-58). According to the present invention, mouse T cell lymphoma WR19L and mouse fibroblastoma L929 cells are transformed with the above expression plasmid. The flow cytometry analysis of the transformants revealed that the Fas antigen is expressed in very large amounts on their surfaces. It has been further confirmed that the transformed cell lines exhibit a dose-dependent response to the anti-Fas antibody and die. Through the observation of morphological changes, fragmentation of chromosomes and the like, it has been made clear that these cells die due to apoptosis.

The present invention provides DNAs coding for human cell surface antigen Fas and expression vectors for carrying the DNA.

The cDNA (e.g. pF58) encoding the Fas antigen of the present invention can be isolated by ordinary methods from the transformant (e.g. Esherichia coli, pF 58 which carries the plasmid pF 58 was originally deposited as a domestic microorganism deposit (FERM P-12192) at the Fermentation Research Institute, Agency of Industrial Science and Technology, Ministry of International Trade and Industry, Japan (FRI),on Apr. 12, 1991 and converted into an international one (FERM BP-3826) under the Budapest Treaty.

The cloning of CDNA coding for the human Fas antigen according to the present invention can be carried out according to conventional methods in the art. The total RNAs are prepared from cells expressing human Fas antigen (e.g. KT-3 cell) and poly(A)RNAs are selected. Then, a double stranded CDNA is synthesized by using reverse transcriptase or the like enzyme and is introduced into a mammal expression vector (e.g. pCEV4 , (Ito et al., 1990) to prepare cDNA libraries. The cDNA libraries (e.g. CDNA libraries of about 8×10 5 independent clones) are transfected into mammal cells (e.g. COS-7 cell) by the spheroplast fusion method or the like. After the transfection (e.g. at 72 hr posttransfection), the transfected mammal cells (e.g. the transfected COS-7 cells) are incubated with anti-Fas antibody (e.g. mouse anti-Fas antibody (IgM)), and the mammal cells expressing the Fas antigen (e.g. the COS cell expressing the Fas antigen) are recovered by the panning procedure [Seed and Aruffo, Proc. Natl. Acad. Sci. USA 84, 3365-3369, 1987] using goat anti-mouse IgM or the like.

The extrachromosomal DNA is prepared from the adherent mammal cells (e.g. the adherent COS cells) according to the method of Hirt [J. Biol. Cham. 264, 14929-14934, 1967] or the like, and introduced into Escherichia coli or the like. The resultant colonies are pooled, used for spheroplast fusion, etc. with mammal cells (e.g. COS cell), and the panning is performed as described above. This procedure is repeated (e.g. three times) to obtain individual clones (e.g. 14 individual clones (pF1 to pF14)). Then, mammal cells (e.g. COS cells) are transfected with selected clones (e.g. pF1 having 3.0 kb insert and pF3 having 1.5 kb insert) among the individual clones. The resulting cells are analyzed by the flow cytometry using an anti-Fas antibody and the like. In a preferred embodiment of the present invention, it has been found that two cDNAs code for proteins that have the Fas antigen determinant. The pF1 and pF3 have been subjected to the restriction enzyme mapping and the DNA sequencing analysis.

As a result, it has been found that the pF1 and pF3 share identical sequences at the 5′ end including about 500 bases. However, their sequences at the 3′ end diverge completely (see FIG. 3 A).

Next, the original cDNA libraries of cells expressing human Fas antigen are screened by the colony hybridization using an isolated DNA fragment derived from cDNA coding for proteins related to the human Fas antigen (e.g. XhoI-BamHI DNA fragment at the 5′ end of the pF3). As a result, clones which have full-length DNA encoding Fas antigen are obtained.

In a preferred embodiment of the present invention, it has been found that ten clones are isolated and subjected to restriction enzyme mapping. These cDNAs contained inserts of 1.8 to 2.6 kb, showed identical restriction maps and overlapped each other.

The longest cDNA clone (pF58) was selected from the resulting clones. FIG. 3 shows the restriction map of the longest cDNA clone (pF58), and FIG. 1 and 2 show the nucleotide sequence and the predicted amino acid sequence.

The pF58 cDNA has a long open reading frame of 1008 nucleotides capable of coding for a protein consisting of 335 amino acids. The hydropathy analysis of the predicted amino acid sequence indicates the presence of a signal sequence at the N-terminal end (FIG. 3 B). Comparison of the N-terminal sequence with typical signal peptide cleavage sites suggests that the mature Fas antigen would lack the signal peptide portion and be a protein consisting of 319 amino acids having a calculated molecular weight of about 36,000. This Fas antigen protein consists of an extracellular domain of 157 amino acids, a membrane-spanning domain of 17 amino acids, and a cytoplasmic domain of 145 amino acids.

Western blotting analysis of the membrane fractions from KT-3 cells and the WR19L transformant clone, F58-12A, expressing the Fas antigen using the anti-Fas antibody, shows a specific band with an apparent molecular weight of about 43,000. This value is in good agreement with the above calculated value (about 36,000) from the standpoint in which sugar moieties are bonded to two potential N-glycosylation sites found in the extracullular domain of the Fas antigen (see FIG. 1 ).

Moreover, the KT-3 cells are subjected to the northern hybridization using the Fas antigen cDNA or its fragment as a probe to detect two bands at 2.7 and 1.9 kb. By taking the presence of the poly(A) tail into consideration, it is considered that the larger mRNA is almost identical to the size of the above pF58 cDNA. It is therefore considered that pF58 is a full-length cDNA for the larger mRNA. If human colon carcinoma HT-29 cells are treated with 300units/ml human INF-γ for 7 hours prior to harvest, both large and smaller mRNAs for the Fas antigen are expressed distinctly.

Forty percent of the cODNA clones isolated from the KT-3 cDNA libraries by the colony hybridization possessed a length of about 1800 bp. Since the potential poly(A) addition signals can be found at nucleotide position 1831 to 1836 (base Nos. 1831 to 1836) in the 3′ noncoding region of pF58 cDNA (FIG. 2 ), the two different mRNAs for human Fas antigen, found by the northern hybridization, are probably generated by an alternative use of two different poly(A) addition signals.

According to the present invention, the cDNA coding for the human Fas is cloned and the nucleotide sequence is clarified. For people skilled in the art, therefore, it pertains within the scope of the present invention to construct an expression vector capable of expressing a recombinant Fas antigen in a suitable host system. Then, by transforming the host cells with the thus constructed expression vector, the transformed cells are cultured under the conditions suitable for expressing the DNA encoding the Fas antigen in order to prepare a recombinant human Fas antigen. The thus obtained recombinant human Fas antigen is useful in clarifying the apoptosis mechanism of various cells such as immune system cells, and is further effective in preparing monoclonal anti- bodies that spesifically react with tumor cells expressing Fas or of value for the study, research and clinical test of those related to cytolytic activity of TNF.

For instance, the analysis of the cDNA coding for the human Fas antigen as obtained in Example 1 and the analysis of the corresponding encoded amino acid sequences, indicate that the Fas antigen belongs to a group of cell surface receptor proteins.

Here, the proteins thus provided include ones that may be encoded by the DNA of the present invention and may be defined to be the human Fas antigen and the functional homologs thereof. They may be cell surface proteins that are recognized by a monoclonal antibody capable of specifically recognizing the human Fas antigen and that induce apoptosis in the cells with the antibody alone without the presence of any other cytotoxic factor such as complement and the like. Particularly, the present invention provides proteins having the amino acid sequence disclosed in FIGS. 1 and 2 or peptides which are a part of the amino acid sequences thereof.

With the current technical level in this field of science, it will be esay to introduce mutation such as deletions, additions, insertions and/or substitutions to the amino acid sequence without changing fundamental properties (e.g. physical properties, physiological or biological activity, immunological activity, etc.) of the proteins. For instance, substitution of a hydrophobic amino acid residue with other hydrophobic amino acid residue, or of amino acid residue having positive electric charge with other amino acid residue having positive electric charge, mutual substitution among Glu and Asp or Lys, His and Arg, substitution among Ile, Val, Met and Leu groups, substitution among Gly, Ala, Ser and Cys groups, and substitution among Trp, Tyr and Phe groups may be predicted. For easy purification of the proteins of the present invention, furthermore, other proteins such as β-galactositase of Eschaerichia coli or mouse IgG Fc fragment may be added to the N-terminal side or/and the C-terminal side of the proteins by the genetic engineering method, or the amino acid sequence may be partly cleaved or substituted by the similar method in order to more deeply analyze the function of the proteins, as can be easily contrived by people skilled in the art. Therefore, such human Fas antigen amino acid mutants are also encompassed by the present invention. For instance, soluble Fas antigens indicated by amino acid Nos.1 to 157 as shown in FIG. 1 are preferred examples of such mutants.

The nucleotide sequences of cDNAs coding for the human Fas antigen of the present invention are shown in FIGS. 1 and 2 . It would be understood that Fas derivatives having substantially the same functions as the natural Fas antigen determinant can be obtained from the above DNAs by inserting, deleting, substituting or cleaving the nucleotides. Therefore, the DNAs thus derived are also encompassed by the scope of the present invention.

The insertion, substitution or deletion of the nucleotides can be carried out by, for example, the site directed mutagenesis, homologous recombination, cleavage with restriction enzymes, or ligation with ligase. The above methods can further be suitably combined with the primer extension using synthetic DNA fragments as primers or the polymelase chain reaction. These methods can be carried out in compliance with the methods disclosed in, for example, Sambrook et al. “Molecular Cloning, A Laboratory Manual, 2nd edition, Cold Spring Harbor Laboratory, 1989, Muramatsu (Ed.) “Labomanual Genetic Engineering” Maruzen Co., 1988, Erlich HE, (Ed.) [PCR Technology, Principle of DNA Amplification and Its Application] Stockton Press, 1989, or in compliance with the modified methods thereof.

In the technical field of genetic engineering, furthermore, it has been known to substitute the bases in the base sequence for other base sequence without changing the amino acid sequence that is encoded thereby. Most of the amino acids are encoded by a plurality of genetic codes. For instance, Val is encoded by any one of GTT, GTA, GTC or GTG and Ala is encoded by any one of GCA, GCT, GCC or GCG. Therefore, the genetic base sequences of the present invention include base sequence substituted mutants that accompany the degeneracy of genetic codes.

From the disclosure of the present invention, furthermore, it would be easy in the art to add a base sequence such as a promoter or an enhancer to the 5′ end side in order to produce a large amount of protein encoded by the DNA base sequence, in a transformant, to add a poly A addition signal base sequence to the 3′ end side in order to stabilize the mRNA after the transcription, and/or to remove bases from or,insert bases in the base sequence of the present invention in order to obtain mutant proteins from which amino acids are partly removed or to which amino acids are partly added in an attempt to further extensively analyze the function of the proteins encoded by the base sequence of the present invention. Therefore, the present invention further encompasses the base sequences having one or more bases that are added, altered, removed or inserted on the 5′ end side or on the 3′ end side and/or between them in the base sequence of the present invention.

The DNAs of the present invention include DNAs complementary to the DNAs encoding Fas or their fragments, DNAs capable of hybridizing with DNAs which are complementary to the DNAs encoding Fas or their fragments, and DNAs capable of hybridizing with human Fas protein cDNA fragments.

The expression vectors containing DNA coding for the human Fas antigen of the present invention can be constructed by methods known in the art. The vector suitable for expressing human Fas anti- gen DNA may have a promotor for initiating transcription closely on the upstream side of the DNA inserted site. Suitable promoters have been known in the art and can be selected by depending upon the functional characteristics in the host cells. Examples include a promoter of SV40 virus early gene, promoter of peptide chain elongation factor EF-1α, promoter of metallothioneine gene, promoter of β-actin, and promoter of CMV virus that can be used for the expression in the animal cell systems, as well as a promoter of T7 polymelase and promotor of β-galactositase gene that can be used for the expression in bacteria, particularly Escherichia coli, and promoters of phosphoglyceraldehyde dehydrogenase and alcohol dehydrogenease that can be used for the expression in yeasts. It is desired that a termination signal exists at a position downstream of a human Fas DNA inserted site.

In the case of animal cells, such regulators may be those from the human Fas sequence or from other sources of genes. When Escherichia coli is used, however, such regulators should desirably be from the Escherichia coli gene.

It is desired that the vector comprises a marker for selection such as a drug-resistant marker. A particularly desired example of the marker may include a neomycin-resistant gene, etc. an expression vector containing Fas DNA and a plasmid coding for drug resistance such as an antibiotic may be subjected to the transformation simultaneously.

In order to construct the expression vector, the DNA coding for the human Fas of the present invention is inserted in a suitable vector which can be selected from those already known in the art by taking into consideration of the promoters, termination signal, selection marker and other conditions. Examples of the DNA vector in which the cDNA of the invention is inserted and which is introduced into the host culture cells for expression the cDNA include pKCR, pEF-BOS, CDM8, pCEV4, bovine papilloma virus DNA for expression in the animal cells, pGEMEX, pUC, etc. for expression in Escherichia coli, as well as pYG100 YCpAD1, etc. for expression in the yeasts.

Any culture cells may be used for the expression of human Fas antigen of the present invention as long as they are self- replicable and are capable of expressing the DNAs of the present invention. Examples include procaryotic microorganisms such as Escherichia coli and eucaryotic microorganisms such as yeasts (Saccharomyces, such as S.cerevisiae ), as well as tissue culture cell lines derived from eucaryotic living things. Examples of Escherichia coli strains suitable for hosts include HB101, DH1, x1776, JM101, and JM109 of which the transformants can be easily sorted depending upon their resistance against drugs and enzymatic activities. Tissue culture cell lines include culture cells drived from insects, birds, mouse, rat, hamster, ape and human.

Preferred examples are L cells, 3T3 cells, FM3A cells, CHO cells, COS cells, Vero cells, Hela cells and primary-cultured fibroblasts. Suitable host-vector systems and their use have been known in the art. Among them, any systems can be arbitrarily selected as long as they are suitable for expressing the DNAs of the present invention.

The proteins of the present invention can be produced in such a system by cultivating a host (transformant) under the conditions suitable for the growth and capable of functioning the promoter of vector possessed by the host. These conditions can also be suitably selected and put into practice by people skilled in the art.

The present invention will be described more concretely by the following examples, but they should not be interpreted as. limiting the invention in any manner.

In the specification, the technical terms, abbreviations and symbols are those which are conventionally used in the art unless otherwisely stated. Moreover, the processes were conducted by making reference to Sambrook et al. “Molecular Cloning, A Laboratory Manual, 2nd edition”, Cold Spring Harbor Laboratory, 1989, Imai Fumio et al., “Introduction of Recombinant Gene into Cells and Expression”, Proteins, Nucleic Acids, Enzymes, Special Edition 28 (14), 1983, Yoshio Okada, “Summary of Cellular Engineering Technology”, Experimental Medicine, Special Edition 7 (13), 1989, etc.

EXAMPLE 1

Cloning of cDNA Encoding Human Fas

(1) Cell and Antibody

Human lymphoma cell lines KT-3 (8×10 4 , kindly provided by Dr. Shimizu, Kanazawa Medical University) were grown in RPMI 1640 medium supplemented with 10% fetal calf serum (FCS) and 5 ng/ml human recombinant IL-6 (kindly provided by Ajinomoto Co., Inc.). The cell culture (total volume: 2 l) was incubated at 37° C. for 2 days under 5% CO 2 -95% air.

Mouse T cell lymphoma WR19L cells (ATCC TIB52) (kindly provided by Dr. T. Kinebuchi, Tokyo Institute for Immunopharmacology, Inc.) were grown in RPMI 1640 medium containing 10% FCS.

Monkey COS-7 cells (ATCC CRL1651) and mouse L929 cells were grown in Dulbecco's modified Eagle medium (DMEM) containing 10% FCS.

Mouse anti Fas monoclonal antibody (IgM) was prepared in the same manner as mentioned above [Yonehara et al. J. Exp. Med., 169: 1747-1756, 1989] and purified by column chromatography on hydroxyapatite.

(2) Construction of cDNA Library

Total RNA (2.7 mg) was prepared from the KT-3 cells (1.2×10 9 ), by the guanidium isothiocyanate/acid phenol method [Chomczynski and Sacchi, Anal. Biochem.,162, 156-159 (1987)] and poly(A)RNA (137 μg) was selected by means of an oligo(dT)-cellulose column chromatography. The poly(A)RNA (5 μg) was employed in synthesis of CDNA. Double strand cDNA primed with random hexamer oligonucleotide (pdN6) or oligo(dT) was synthesized in the same manner as described in the report [Fukunaga et al., Cell, 61: 341-350 (1990)] except that M-MLV RNaseH—reverse transcriptase was employed instead of the AMV reverse transcriptase.

After addition of BstXI non-palindromic adapter (2 μg), DNA ligase (350 units), and ATP (final concentration: 1.0 mM), the mixture was reacted at 4° C. for 18 hours to ligate the adaptors to both ends of the synthesized double stranded DNA. The cDNA larger than 2 kb was recovered from the agarose gel and 0.25 μg of the recovered cDNA was ligated to BstXI-digested mammalian expression vector pCEV4 (0.2 μg) [Itoh et al., Science, 247, 324-327 (1990)] to construct the cDNA library. E. coli VM1100 cells were transformed with the oDNA by the electroporation method [Dower et al., Nucleic Acids Res., 16, 6127-6145 (1988)].

The individual clones of about 4.3×10 5 from the oligo(dT)-primed cDNA library were mixed with the clones of about 4.0×10 5 from the randam hexamer-primed cDNA library and transfection with COS-7 cells was carried out as described below to recover the cDNA clones.

(3) Recovery of cDNA by Panning

The panning plates (panning dishes) were prepared as described below.

The bacterial 6 cm dishes (plates) (Falcon 1007) were incubated at room temperature for 90 minutes with 3 ml of 50 mM Tris-HCl (pH 9.5) containing 10 μg/ml goat anti-mouse IgM (Cappel). The plates were washed three times with 0.15 M NaCl and then incubated at room temperature overnight with 3 ml of phosphate-buffered saline (PBS).

One hundred and eight 6 cm dishes each containing 50% confluent monkey COS-7 cells (ATCC CRL1651), which were incubated in Dulbecco's modified Eagle medium containing 10% FCS, were transferted by the spheroplast fusion method [Sandri-Goldrin et al., Mol. Cell. Biol., 1, 743-752 (1981)] using the KT3 CDNA library comprising about 8×10 5 individual clones as described above.

After 72 hours from the transfection, the cells were detached from the dishes by incubation in PBS containing 0.5 mM EDTA and 0.02% NaN 3 (PBS/EDTA/NaN 3 ) at 37° C. for 30 minutes. The detached cells were pooled, collected by centrifugation and then suspended in 9 ml of cold PBS/EDTA/NaN 3 containing 10 g/ml anti-Fas antibody. After incubation on ice for 60 minutes, the cells were diluted with an equal amount of PBS/EDTA/NaN 3 and centrifuged at 1000 rpm for 5 minutes through PBS/EDTA/NaN 3 containing 2% Ficoll 400.

The pelleted cells were resuspended in 27 ml of PBS/EDTA/NaN 3 supplemented with 5% FCS and filtrated through Nylon meshes (pore size of 100 μm) to remove the aggregates. Then, the cells were distributed into 54 panning plates, each containing 5 ml of. PBS/EDTA/NaN 3 and 5% PCS. After incubation at room temperature for 2 to 3 hours, the Fas-expressing cells were adhered onto the plates and then nonadhering cells were removed by gently washing three times with 2 ml of PBS/EDTA/NaN 3 containing 5% FCS. Then, the extrachromosoval DNA was prepared from the adhered COS cells according to the Hirt method [(1967), J. Biol. Chem. 264, 14929-14934, 1967].

More specifically, into each plate was placed 0.4 ml of 0.6% SDS solution containing 10 mM EDTA and each plate was incubated at room temperature for 20 minutes. The lysates were collected into microfuge tubes, NaCl was added up to 1 M and the tubes were placed on ice for at least 5 hours. After centrifuged at 13,000 rpm, for 5 minutes, the supernatants were extracted with phenol/chloroform and the DNA was recovered by ethanol precipitation. With the DNA recovered from the first round of panning was transformed Escherichia coli VM1100 to give about 3.2×10 5 colonies. They were subjected to sphereplast fusion with COS cells in 48 plates, each being of 6 cm. Panning was performed with 24 plates in the same manner as described above and the DNA was prepared from the adhered cells. The so recovered DNA was transformed to give about 10,000 colonies, which were used for the third cycle of the spheroplast fusion with COS cells (24 plates, each being of 6 cm) and panning was performed in 12 plates, each being of 6 cm, to prepare the DNA from the adhered cells.

Transformation of E. coli VM100 was performed with the DNA finally obtained by the said three procedures and, among 2.8×10 5 clones, 14 of the resultant clones (pF1-pF14) were analyzed.

By digestion of the 14 plasmid DNA's with restriction enzyme, it has been elucidated that one group has the same insert of 3.0 kb (pF1, 2, 5, 11), while another group has the same insert of 1.5 kb (pF3, 4, 6, 7, 9).

By using the pF1 and pF3 among them, COS cells were subjected to transfection and the cells were analyzed by a flow cytometry using anti-Fas antigen to confirm the two cDNAs code for Fas antigen determinant.

The restriction mapping and DNA sequence analysis of pF1 and pF3 showed that they share identical sequences at the 5′ end up to 0.57 kb, but their sequences at the 3′ end diverge completely.

Then, the cDNA libraries of the above-mentioned KT-3 cells were screened by colony hybridization using the XhoI-BamHI DNA fragment (about 520 bp) as the 5′ end of pF3. Ten colonies were obtained from 2×10 5 clones, said 10 clones showing identical restriction maps and overlapped each other. The longest cDNA clone was selected and designated pF58. Schematic representations and restriction maps of the pF58 and the said pF1 and pF3 are shown in FIG. 3 A. In the FIG. 3A , the open box represents the open reading frame, the hatched box represents the signal sequence, and the black box represents the transmembrane region, respectively. In the representations for pF1 and pF3, the solid lines show identical sequence to that of pF58, while the dotted lines show difference sequence from that of pF58. However, the pF3 cDNA contains a single base (T) deletion at the position indicated with an arrowhead, the point of which is different from the pF58 cDNA.

FIG. 3B shows a hydropathy plot of human Fas antigen, which was obtained by the method of Kite and Doolittle [J. Mol. Biol., 157, 105-132 (1982)]. The numbers under the plot show positions of the amino acid residues of the precursor protein.

Then, the nucleotide sequence of the clone pF58 and its predicted amino acid sequence were determined. The results are shown in FIG. 1 and FIG. 2 , which are identified in the Sequence Listing as SEQ ID NO:1 and SEQ ID NO:2.

The cDNA analysis has elucidated the following points:

(1) The cDNA consists of 2534 bp and has a poly(A) addition signal (ATTAAA) at the 3′-end.

(2) There is a long open reading frame (1,008 nucleotides). The open reading frame can code for a protein consisting of 335 amino acids, starting from the initiation codon at the nucleotide positions 195 to 197 and ending at the termination codon TAG at the positions 1200 to 1202.

The results of the hydropathy analysis of the amino acid sequence suggested the presence of a signal sequence at the N-terminal end (See, FIG. 3 B). Comparison with typical signal peptide cleavage sites suggested that the mature protein start at the 17th amino acid (Arg).

Therefore, the mature Fas antigen is a protein consisting of 319 amino acids with a calculated molecular weight of 36,000 and has the transmembrane segment consisting of 17 uncharged amino acids from Leu-158 to Val-174. And, it is followed by 3 basic amino acids at the cytoplasmic domain, as observed in other membrane-spanning proteins.

It has been indicated from the above results that this protein consists of an extracellular domain of 157 amino acids, a membrane-spanning domain of 17 amino acids and a cytoplasmic domain of 145 amino acids and that the extracellular domain is rich in cystein residue (18 residues in 157 amino acids) and the cyto- plasmic domain is relatively abundant in charged amino acids (24 basic amino acids and 19 acidic amino acids in 145 amino acids).

In FIG. 1 and FIG. 2 showing the nucleotide sequence and amino acid sequence of the Fas protein, the numbers above and below each line refer to the nucleotide position and the amino acid position, respectively. Amino acid numbers start at Arg-1 of the mature Fas protein. The transmembrane domain is underlined and two potential N-linked glycosylation sites (Asn-X-Ser/Thr) are indicated by asterisks. Three poly(A) addition signals (ATTAAA) are indicated as overlined. The nucleotide deleted in the pF3 is indicated with an arrowhead.

(3) Comparison in sequences of the Fas antigen with other members of the NGFR/TNFR family.

Comparison of the amino acid seqeunce of the Fas antigen with the sequences of other members of the NGFR/TNFR family was performed. The results are shown in FIGS. 7 ˜ 9 .

FIG. 7 is a schematic representation of the cysteine-rich repeats of the extracellular domain. In open boxes, the cysteines are represented with bars, and the stripped boxes in the cytoplasmic domain represent the conserved region among the Fas antigen, the TNF receptor type I and the CD40 antigen. It has been indicated from this FIG. that the extracellular domains of the TNF receptor, the NGF receptor and the CD40 antigen can be divided into 4 cysteine-rich subdomains, while the Fas antigen and the CDU40 antigen contain 3 subdomains.

FIG. 8 shows the amino acid sequences of the extracellular domains of human Fas (hFas), human TNF receptor type I (hTNFR1) (Schall et al., 1990), human TNF receptor type II (hTNFR2) [Smith et al., Cell, 61, 361-370 (1990)], human NGF receptor (hNGFR) [Johnson et al., Science, 248, 1019-1023 (1986)], human CD40 (hCD40) [Stamenkovic et al., EMBOJ., 8, 1403-1410 (1989)] and rat OX40 (rOX40) [Mallett et al., EMBO J.,9, 1063-1068 (1990)]. Gaps(−) are introduced to optimize matches. Identical amino acids are boxed.

It has been indicated from this FIG. that the positions of the cysteine residues are well conserved. The numbers referring to residues are followed as in references. The amino acid residues conserved among the cysteine-rich repeating units are indicated at the bottom of the sequence. FIG. 9 is a comparison representation of the cytoplasmic domains of the Fas, the TNF receptor I and the CD40. The amino acid sequences of the corresponding regions of the hCD40, hfas and hTNFR1 are aligned. Identical and conserved amino acids are boxed in solid and dotted lines, respectively.

It has been established that the Fas of this invention belong to the group of such cell surfase proteins.

EXAMPLE 2

Preparation of Transformants Expressing Fas Antigen

The 2.6 kb XhoI fragment containing the Fas cDNA was prepared from the plasmid pF58 (2 μg) and transfected into the BstXI site of a mammalian expression plasmid pEF-BOS [Mizushima and Nagata, Nucleic Acids Res.,18, 5322 (1990)] using a BstXI adapter to construct the expression vector pEFF58 containing the Fas-coding cDNA under the control of human peptide chain-elongation factor 1α gene.

(1) Transformation of Mouse Fibroblastoma L929 Cells was Performed According to the Following Method:

L929 cells 1×10 6 , which were grown in DMEM containing 10% FCS, were cotransfected with 0.2 μg of pSTneoB containing neomycin-resistant genes and 20 μg of ApaL1-digested pEFF58 in a 10 cm plate by the calcium phosphate coprecipitation method [Sambrook et al. “Molecular Cloning, A Laboratory Manual, 2nd edition”, Cold Spring Harbor Laboratory, 1989], followed by treatment with glycerol. After 12 hours from the transfection, the cells were treated with trypsin, diluted ten times and neomycin-resistant cells were selected in a medium containing 0.4mg/ml G-418.

After sufficient growth, the cells were washed with PBS/EDTA/NaN 3 containing 5% FCS and incubated for 60 minutes on ice in the same buffer containing 10 μg/ml mouse anti-Fas antigen. The expression of the Fas antigen in the transformants was examined by the following processes:

The cells were washed to remove the unbound anti-Fas antibody and then stained for 30 minutes on ice with 10 μg/ml FITC-conjugated goat anti-mouse IgM (Cappel). The cells were centrifuged at 1,000 rpm for 5 minutes through a cushion of PBS/EDTA/NaN 3 containing 2% Ficoll, and analyzed on a FACSCAN (Becton Dickson Instruments, USA).

(2) Transformation of Mouse T-cell Lymphoma WR19L Cells was Performed by the Following Method:

WR19L cells (1×107 in 0.8 ml, ATCC TIB52, kindly provided by Dr. T. Kinebuchi, Tokyo Institute for Immunopharmacology, Inc.), which were grown in RPMI1640 containing 10% FCS, were cotransfected with 2.5 μg/ml EcoRI-digested pMAMneo (Clontech) and 25 μg/ml VspI-digested pEFF58 by electroporation [Potter et al., Proc. Natl. Acad. Sci. USA, 81, 7161-7165 (1984)] [at 290V, with a capacitance of 950 μF; Gene Pulser (Bio-Rad)]. The cells were cultured in a growth medium in 96-well microtiter plates (0.1 ml/well) for 2 days and neomycin-resistant clones were selected in a medium containing G-418 at a final concentration of 900 μg/ml. After 9 days, the expression of the Fas antigen in individual G-418-resistant transformants was analyzed on a flow cytofluorometer by mouse anti-Fas antibody and the Fas-positive cells were cloned by a limiting dilution method. Then, the WR19L transformant clone, F58-12a, expressing the Fas antigen was analyzed by a Western Blotting method.

(3) Western Blotting of F58-12a

Membrane fractions from the mouse WR12L cell line, its transformant clone expressing the Fas antigen (58-12a) and human KT-3 were analyzed by Western Blotting with anti-Fas antibody on control IgM. The results showed a specific band with an apparent molecular weight of 43,000. This value is in good agreement with that calculated from the Fas antigen amino acid sequence, in considering the difference wherein the sugar moieties may be attached to the two potential N-glycosylation sites on the extracellular domain of the Fas antigen as shown in FIG. 2 .

Experimental Example 1

Cytolytic Activity of Anti-Fas Antibody on Fas-Expressing Cells

As described hereinabove, mouse anti-Fas monoclonal antibody showed a cytolytic effect on human cells (U-937, HL-60, A637 or FL cells), but the antibody does not react with mouse cells [Yonehara et al., J. Exp. Med. 169: 1747-1756, 1989].

In this Example, it was examined whether the polypeptide coded by the present pF58 cDNA may mediate the cytolytic activity of anti-Fas antibody. Mouse WP19L and mouse L929 were transformed as described in Example 2 to prepare transformant cells expressing Fas antigen. These cells are different in the point wherein L929 cells can be killed by TNF in the presence of actinomycin D, while WR19L cells are susceptible to the cytolytic activity of TNF in the presence or absence of any metabolic inhibitors.

As described hereinabove, the expression plasmid pEFF-58 and a plasmid carrying the neo-resistance gene were cotransfected into WR19L cells or L929 cells and selection in the presence of G-418 afforded several G-418-resistant clones.

Then, parental WR19L and L929 cells, 2 transformants derived from WR19L (58-12a and 58-80d) and 2 clones derived from L929 (LB1 and LBII) were stained with anti-Fas antibody (IgM) and anti-mouse IgM antibody bound with PITC, followed by subjecting to flow cytofluorometry.

The results are shown in FIG. 4 , wherein A: WR19L; B:58-12a; C: 58-80d; D: L929; E: LB1; F: LB11.

As apparent from the FIG. 4 , the parental cells, mouse WR19L and L929 cells, did not express the Fas antigen, while the WR19L transformant cells (58-12a, P58-80d) and L929 cells (LB1 and LB11) extremely abundantly expressed the Fas antigen on their surfaces.

Then, the cytolytic effect of the Fas antibody was examined using the Fas antigen-expressing cells.

The mouse WR19L cell and its transformant clones (58-12a and 58-80d) were incubated with various concentrations of anti-Fas antibody (01: g/ml) at 37° C. for 24 hours. Viable and dead cell counts were determined by the trypan blue exclusion method. The results are shown in FIG. 5 , wherein open squares represent WR19L, closed circles represent 58-12a and closed squares represent 58-80d. As apparent from the FIG. 5 , the F58-12a and F58-80d cell lines responded to the anti-Fas antibody in a concentration-dependent manner. The half-maximal response was obtained at 0.1 μg/ml concentration of the anti-Fas antibody and the cells were completely killed by incubation for 24 hours in the presence of 1 μg/ml said antibody.

The cytolytic effect of the anti-Fas antibody on the L929 transformant clones was examined according to the following method.

The L929 cells and the transformant clones expressing recombinant human Fas antigen (LB1 and LB11) were dispersed onto 96-well microtiter plates (25,000 cells/well) and incubated for 24 hours. Actinomycon D was added at a final concentration of 0.5 μg/ml and the cells were incubated with various concentrations of anti-Fas antibody (30ng˜2 μg/ml) at 37° C. for 17 hours. Then, the cells were stained with a solution of 0.75% crystal violet in 50% ethanol, 0.25% NaCl and 1.75% formaldehyde at room temperature for 20 minutes. Dye uptake was assessed by the OD value measured at 540 nm using Micro-ELISA autoreader, as expressed as a percentage of the OD measured value without anti-Fas antibody. The results are shown in FIG. 6 , wherein open squares represent L929, closed circles represent LB1 and closured squares represent LB11.

As apparent from the FIG. 6 , the LB11 and LB1 cell lines responded to the anti-Fas antibody in the presence of actinomycin D in a similar concentration-dependent manner to that of the WR19L cells expressing Fas.

In any causes, the parental mouse WR19L and L929 were not affected by the anti-Fas antibody at a concentration of 1 μg/ml under the same conditions.

Experimental Example 2

Apoptosis Induced by Anti-Fas Antibody

Apoptosis of cells induced by Fas was proved according to the following method:

(1) Fragmentation of Chromosomal DNA

The WR19L cell and its transformant clones, 58-12a and 58-80d cells, were incubated in the presence of 3OOng/ml anti-Fas antibody or 60 ng/ml mouse TNF-α. Before incubation and after 1 hour, 2 hours and 3 hours incubation, total DNA was prepared from cells and analyzed by 2% agarose gel electrophresis in the presence of 0.5 ug/ml ethidium bromide. The fragmentation of chromosonal DNA was observed. The fragmented DNA was separated in a laddered pattern and its minimum size was approximately 180 bp. This laddered DNA fragments were observed within 1 hour of incubation and more than 60% of chromosonal DNA was fragmented after 3 hours of incubation. On the other hand, the chromosomal DNA from the parental WR19L cells remained as a high molecular weight form even after incubation with the anti-Fas antibody.

A similar DNA fragmentation was observed in the parental WR19L cells and their transformant cells treated with 60 ng/ml TNF. This was similarly observed in L929 cells.

These results suggest that the specific binding of the Fas antibody to the Fas antigen on the cell surface induces an endonuclease which digests the chromosonal DNA. They are consistent with those properties of apoptosis observed in various systems [Schmid et al., (1987); Ucker, (1987); Smith et al., (1989); Williams et al, (1990), Nature 343, 76-79, 1990]. And, the expression of the Fas antigen in mouse WR19L and L929 cells does not affect a cell-killing effect of TNF and the transformant cells were also killed with mouse TNF-A at the same concentration as in parental cells.

(2) Morphological Changes

Morphological changes in the L929 transformant expressing the Fas antigen were examined.

Morphological changes of the LB1 cells were initiated after incubation in the presence of 0.5 μg/ml actinomycin D and in the presence of 1 μg/ml anti-Fas antibody for 3 hours and, after 5 hours, many typical apoptosic blebs were seen on cell surface. Then, almost all cells were detached from plates within 24 hours. Such morphological changes of the LB1 cells were not observed even in the presence of actinomycin D unless the Fas antibody was present. And, the anti-Fas antibody did not give any morphological changes to parental L929 cells.

It becomes apparent, as described in the above Experimental Example, that the human Fas antigen obtained in this invention can mediate apoptosis of cells. Recombinant human Fas. can be prepared using the present cDNA by a recombinant DNA technology. Further, the monoclonal antibody to specifically act the human Fas can be also prepared readily in a well-known manner. Thus, these are provided diagnostic and therapeutic means for diseases and disorders in which the cells expressing the Fas antigen would participate.

According to the disclosure related to DNA coding for the human Fas antigen, proteins encoded by the DNA, amino acid sequences thereof and methods for treating and identifying them of the present invention, it becomes possible to apply them to the below-mentioned fields of basic studies and the fields applied industries. The present invention encompasses those that are thus obtained.

At least a part of the DNAs of the present invention may be adopted to variations in order to study the kinds and amounts of expression tissues of the corresponding mRNAs. The results may serve as data which are very useful in estimating the functions of the coded proteins in vivo. At least a part of the base sequences may be adopted to variations in order to isolate Fas antigen genome DNAs. These results may offer data that are of value for analyzing the structure of the Fas antigen genes and for estimating the mechanism of expression control.

Moreover, the sequence of the present invention can be used in studying the polymorphism of Fas antigen genes, enabling the correlation between the genetic diseases and Fas to be closely studied. It is of course allowable to use the DNAs of the present invention as probes for isolating the genes that correspond to Fas antigens of experimented animal species other than human.

In recent years, so-called transgenic animal technology has been put into practice to create an animal in which expression of particular genes are artificially reinforced or suppressed by triggering genetic homologous recombination phenomenon to the gametes or generated early embryo of a higher animal, and the DNA of the present invention can be applied to even such technologies. It is estimated that a species of an experimented animal, in which expression of a Fas gene is reinforced or suppressed, may serve as a new model animal of diseases. It is further possible to study correlation between the Fas antigen genes or Fas antigens and the diseases using these animals, as well as to develop novel therapeutic agents for medical treatment.

The DNAs of the present invention make it possible to produce human Fas antigens in large amounts based on the genetic engineering method. The thus produced Fas antigens are not only useful in the analysis of the functions but can further be used in preparing antisera and monoclonal antibodies. The antiserum and the monoclonal antibody are useful in analyzing the distribution or dinamics of Fas antigens in the blood or tissues, and, hence, the study of correlation relative to various diseases will enable the immunological diagnosis to be carried out.

By using Fas antigens produced in large amounts, furthermore, it is allowed to clone genes coding for proteins that bind to Fas. The cDNAs coding for proteins that bind to Fas may be cloned and selected from expression libraries of various tissues such as placenta by utilizing the reactivity with human Fas antigen as an indicator. In this case, it is allowed to use a soluble Fas antigen lacking a membrane-spanning region or a modified Fas antigen linked with a genetic product encoded by other genes that may serve as markers. The cDNA thus obtained may be applied to the recombinant DNA technology which makes it possible to express a protein capable of reacting with the Fas antigen. Moreover, the human Fas antigen may be bound to a carrier (including a resin) such as SEPHAROSE™ activated with cyanogen bromide to prepare an affinity column. For example, human sera, urea or tissue extracts may be chromatographed on the affinity column to obtain proteins capable of reacting with the Fas antigen. It is further possible to clone the cDNAs utilizing the amino acid sequence of purified proteins. For instance, it may be possible to synthesize a primer for PCR, to extract an RNA from various tissues such as thymus or bone marrow lymphocytes, and to clone cDNA by the reverse PCR method.

Furthermore, the soluble Fas antigen lacking a transmembrane region would compete with the Fas antigen on the cell membrane in vivo to suppress its Fas activity. Therefore, such Fas antigen mutants may be applied as medical drugs. It is estimated that what binds to the Fas antigens is not limited to the proteins mentioned above. Therefore, the Fas antigens of the present invention may be used in searching natural or artificially synthesized molecules capable of reacting therewith.

The substances obtained by the above research may be used as agonists or antagonists against the Fas antigens and offer data that are useful in developing new medical drugs. Furthermore, they may be useful in searching agonists and antagonists capable. of working upon the signal transduction mechanism through the studies of the transmission mechanism of secondary and tertially stimulation signals from the outside of cells into the cells throuh Fas antigen.

Since the apoptosis is found in the extinction process of self-component reactive T cells, it is expected that the Fas antigen may be closely related to autoimmune diseases such as articular rheumatism and SLE, and the above-mentioned agonists and antagonists may serve as therapeutic drugs for such diseases.

It goes without saying that the amino acid mutant proteins of the present invention may be of value in the same fashion as mentioned above.

11 2534 base pairs nucleic acid double linear cDNA to mRNA Homo sapiens CDS 195..1202 sig_peptide 195..242 mat_peptide 243..1199 polyA_site 1831..1836 polyA_site 2352..2357 polyA_site 2518..2532 1GACGCTTCTG GGGAGTGAGG GAAGCGGTTT ACGAGTGACT TGGCTGGAGC CTCAGGGGCG 60GGCACTGGCA CGGAACACAC CCTGAGGCCA GCCCTGGCTG CCCAGGCGGA GCTGCCTCTT 120CTCCCGCGGG TTGGTGGACC CGCTCAGTAC GGAGTTGGGG AAGCTCTTTC ACTTCGGAGG 180ATTGCTCAAC AACC ATG CTG GGC ATC TGG ACC CTC CTA CCT CTG GTT CTT 230 Met Leu Gly Ile Trp Thr Leu Leu Pro Leu Val Leu -16 -15 -10 -5ACG TCT GTT GCT AGA TTA TCG TCC AAA AGT GTT AAT GCC CAA GTG ACT 278Thr Ser Val Ala Arg Leu Ser Ser Lys Ser Val Asn Ala Gln Val Thr 1 5 10GAC ATC AAC TCC AAG GGA TTG GAA TTG AGG AAG ACT GTT ACT ACA GTT 326Asp Ile Asn Ser Lys Gly Leu Glu Leu Arg Lys Thr Val Thr Thr Val 15 20 25GAG ACT CAG AAC TTG GAA GGC CTG CAT CAT GAT GGC CAA TTC TGC CAT 374Glu Thr Gln Asn Leu Glu Gly Leu His His Asp Gly Gln Phe Cys His 30 35 40AAG CCC TGT CCT CCA GGT GAA AGG AAA GCT AGG GAC TGC ACA GTC AAT 422Lys Pro Cys Pro Pro Gly Glu Arg Lys Ala Arg Asp Cys Thr Val Asn 45 50 55 60GGG GAT GAA CCA GAC TGC GTG CCC TGC CAA GAA GGG AAG GAG TAC ACA 470Gly Asp Glu Pro Asp Cys Val Pro Cys Gln Glu Gly Lys Glu Tyr Thr 65 70 75GAC AAA GCC CAT TTT TCT TCC AAA TGC AGA AGA TGT AGA TTG TGT GAT 518Asp Lys Ala His Phe Ser Ser Lys Cys Arg Arg Cys Arg Leu Cys Asp 80 85 90GAA GGA CAT GGC TTA GAA GTG GAA ATA AAC TGC ACC CGG ACC CAG AAT 566Glu Gly His Gly Leu Glu Val Glu Ile Asn Cys Thr Arg Thr Gln Asn 95 100 105ACC AAG TGC AGA TGT AAA CCA AAC TTT TTT TGT AAC TCT ACT GTA TGT 614Thr Lys Cys Arg Cys Lys Pro Asn Phe Phe Cys Asn Ser Thr Val Cys 110 115 120GAA CAC TGT GAC CCT TGC ACC AAA TGT GAA CAT GGA ATC ATC AAG GAA 662Glu His Cys Asp Pro Cys Thr Lys Cys Glu His Gly Ile Ile Lys Glu125 130 135 140TGC ACA CTC ACC AGC AAC ACC AAG TGC AAA GAG GAA GGA TCC AGA TCT 710Cys Thr Leu Thr Ser Asn Thr Lys Cys Lys Glu Glu Gly Ser Arg Ser 145 150 155AAC TTG GGG TGG CTT TGT CTT CTT CTT TTG CCA ATT CCA CTA ATT GTT 758Asn Leu Gly Trp Leu Cys Leu Leu Leu Leu Pro Ile Pro Leu Ile Val 160 165 170TGG GTG AAG AGA AAG GAA GTA CAG AAA ACA TGC AGA AAG CAC AGA AAG 806Trp Val Lys Arg Lys Glu Val Gln Lys Thr Cys Arg Lys His Arg Lys 175 180 185GAA AAC CAA GGT TCT CAT GAA TCT CCA ACC TTA AAT CCT GAA ACA GTG 854Glu Asn Gln Gly Ser His Glu Ser Pro Thr Leu Asn Pro Glu Thr Val 190 195 200GCA ATA AAT TTA TCT GAT GTT GAC TTG AGT AAA TAT ATC ACC ACT ATT 902Ala Ile Asn Leu Ser Asp Val Asp Leu Ser Lys Tyr Ile Thr Thr Ile205 210 215 220GCT GGA GTC ATG ACA CTA AGT CAA GTT AAA GGC TTT GTT CGA AAG AAT 950Ala Gly Val Met Thr Leu Ser Gln Val Lys Gly Phe Val Arg Lys Asn 225 230 235GGT GTC AAT GAA GCC AAA ATA GAT GAG ATC AAG AAT GAC AAT GTC CAA 998Gly Val Asn Glu Ala Lys Ile Asp Glu Ile Lys Asn Asp Asn Val Gln 240 245 250GAC ACA GCA GAA CAG AAA GTT CAA CTG CTT CGT AAT TGG CAT CAA CTT 1046Asp Thr Ala Glu Gln Lys Val Gln Leu Leu Arg Asn Trp His Gln Leu 255 260 265CAT GGA AAG AAA GAA GCG TAT GAC ACA TTG ATT AAA GAT CTC AAA AAA 1094His Gly Lys Lys Glu Ala Tyr Asp Thr Leu Ile Lys Asp Leu Lys Lys 270 275 280GCC AAT CTT TGT ACT CTT GCA GAG AAA ATT CAG ACT ATC ATC CTC AAG 1142Ala Asn Leu Cys Thr Leu Ala Glu Lys Ile Gln Thr Ile Ile Leu Lys285 290 295 300GAC ATT ACT AGT GAC TCA GAA AAT TCA AAC TTC AGA AAT GAA ATC CAA 1190Asp Ile Thr Ser Asp Ser Glu Asn Ser Asn Phe Arg Asn Glu Ile Gln 305 310 315AGC TTG GTC TAG AGTGAAAAAC AACAAATTCA GTTCTGAGTA TATGCAATTA 1242Ser Leu ValGTGTTTGAAA AGATTCTTAA TAGCTGGCTG TAAATACTGC TTGGTTTTTT ACTGGGTACA 1302TTTTATCATT TATTAGCGCT GAAGAGCCAA CATATTTGTA GATTTTTAAT ATCTCATGAT 1362TCTGCCTCCA AGGATGTTTA AAATCTAGTT GGGAAAACAA ACTTCATCAA GAGTAAATGC 1422AGTGGCATGC TAAGTACCCA AATAGGAGTG TATGCAGAGG ATGAAAGATT AAGATTATGC 1482TCTGGCATCT AACATATGAT TCTGTAGTAT GAATGTAATC AGTGTATGTT AGTACAAATG 1542TCTATCCACA GGCTAACCCC ACTCTATGAA TCAATAGAAG AAGCTATGAC CTTTTGCTGA 1602AATATCAGTT ACTGAACAGG CAGGCCACTT TGCCTCTAAA TTACCTCTGA TAATTCTAGA 1662GATTTTACCA TATTTCTAAA CTTTGTTTAT AACTCTGAGA AGATCATATT TATGTAAAGT 1722ATATGTATTT GAGTGCAGAA TTTAAATAAG GCTCTACCTC AAAGACCTTT GCACAGTTTA 1782TTGGTGTCAT ATTATACAAT ATTTCAATTG TGAATTCACA TAGAAAACAT TAAATTATAA 1842TGTTTGACTA TTATATATGT GTATGCATTT TACTGGCTCA AAACTACCTA CTTCTTTCTC 1902AGGCATCAAA AGCATTTTGA GCAGGAGAGT ATTACTAGAG CTTTGCCACC TCTCCATTTT 1962TGCCTTGGTG CTCATCTTAA TGGCCTAATG CACCCCCAAA CATGGAAATA TCACCAAAAA 2022ATACTTAATA GTCCACCAAA AGGCAAGACT GCCCTTAGAA ATTCTAGCCT GGTTTGGAGA 2082TACTAACTGC TCTCAGAGAA AGTAGCTTTG TGACATGTCA TGAACCCATG TTTGCAATCA 2142AAGATGATAA AATAGATTCT TATTTTTCCC CCACCCCCGA AAATGTTCAA TAATGTCCCA 2202TGTAAAACCT GCTACAAATG GCAGCTTATA CATAGCAATG GTAAAATCAT CATCTGGATT 2262TAGGAATTGC TCTTGTCATA CCCTCAAGTT TCTAAGATTT AAGATTCTCC TTACTACTAT 2322CCTACGTTTA AATATCTTTG AAAGTTTGTA TTAAATGTGA ATTTTAAGAA ATAATATTTA 2382TATTTCTGTA AATGTAAACT GTGAAGATAG TTATAAACTG AAGCAGATAC CTGGAACCAC 2442CTAAAGAACT TCCATTTATG GAGGATTTTT TTGCCCCTTG TGTTTGGAAT TATAAAATAT 2502AGGTAAAAGT ACGTAATTAA ATAATGTTTT TG 2534 335 amino acids amino acid linear protein not provided 2Met Leu Gly Ile Trp Thr Leu Leu Pro Leu Val Leu Thr Ser Val Ala-16 -15 -10 -5Arg Leu Ser Ser Lys Ser Val Asn Ala Gln Val Thr Asp Ile Asn Ser 1 5 10 15Lys Gly Leu Glu Leu Arg Lys Thr Val Thr Thr Val Glu Thr Gln Asn 20 25 30Leu Glu Gly Leu His His Asp Gly Gln Phe Cys His Lys Pro Cys Pro 35 40 45Pro Gly Glu Arg Lys Ala Arg Asp Cys Thr Val Asn Gly Asp Glu Pro 50 55 60Asp Cys Val Pro Cys Gln Glu Gly Lys Glu Tyr Thr Asp Lys Ala His 65 70 75 80Phe Ser Ser Lys Cys Arg Arg Cys Arg Leu Cys Asp Glu Gly His Gly 85 90 95Leu Glu Val Glu Ile Asn Cys Thr Arg Thr Gln Asn Thr Lys Cys Arg 100 105 110Cys Lys Pro Asn Phe Phe Cys Asn Ser Thr Val Cys Glu His Cys Asp 115 120 125Pro Cys Thr Lys Cys Glu His Gly Ile Ile Lys Glu Cys Thr Leu Thr 130 135 140Ser Asn Thr Lys Cys Lys Glu Glu Gly Ser Arg Ser Asn Leu Gly Trp145 150 155 160Leu Cys Leu Leu Leu Leu Pro Ile Pro Leu Ile Val Trp Val Lys Arg 165 170 175Lys Glu Val Gln Lys Thr Cys Arg Lys His Arg Lys Glu Asn Gln Gly 180 185 190Ser His Glu Ser Pro Thr Leu Asn Pro Glu Thr Val Ala Ile Asn Leu 195 200 205Ser Asp Val Asp Leu Ser Lys Tyr Ile Thr Thr Ile Ala Gly Val Met 210 215 220Thr Leu Ser Gln Val Lys Gly Phe Val Arg Lys Asn Gly Val Asn Glu225 230 235 240Ala Lys Ile Asp Glu Ile Lys Asn Asp Asn Val Gln Asp Thr Ala Glu 245 250 255Gln Lys Val Gln Leu Leu Arg Asn Trp His Gln Leu His Gly Lys Lys 260 265 270Glu Ala Tyr Asp Thr Leu Ile Lys Asp Leu Lys Lys Ala Asn Leu Cys 275 280 285Thr Leu Ala Glu Lys Ile Gln Thr Ile Ile Leu Lys Asp Ile Thr Ser 290 295 300Asp Ser Glu Asn Ser Asn Phe Arg Asn Glu Ile Gln Ser Leu Val305 310 315 119 amino acids amino acid single linear protein not provided 3Gln Asn Leu Glu Gly Leu His His Asp Gly Gln Phe Cys His Lys Pro1 5 10 15Cys Pro Pro Gly Glu Arg Lys Ala Arg Asp Cys Thr Val Asn Gly Asp 20 25 30Glu Pro Asp Cys Val Pro Cys Gln Glu Gly Lys Glu Tyr Thr Asp Lys 35 40 45Ala His Phe Ser Ser Lys Cys Arg Arg Cys Arg Leu Cys Asp Glu Gly 50 55 60His Gly Leu Glu Val Glu Ile Asn Cys Thr Arg Thr Gln Asn Thr Lys65 70 75 80Cys Arg Cys Lys Pro Asn Phe Phe Cys Asn Ser Thr Val Cys Glu His 85 90 95Cys Asp Pro Cys Thr Lys Cys Glu His Gly Ile Ile Lys Glu Cys Thr 100 105 110Leu Thr Ser Asn Thr Lys Cys 115 153 amino acids amino acid single linear protein not provided 4Val Cys Pro Gln Gly Lys Tyr Ile His Pro Gln Asn Asn Ser Ile Cys1 5 10 15Cys Thr Lys Cys His Lys Gly Thr Tyr Leu Tyr Asn Asp Cys Pro Gly 20 25 30Pro Gly Gln Asp Thr Asp Cys Arg Glu Cys Glu Ser Gly Ser Phe Thr 35 40 45Ala Ser Glu Asn His Leu Arg His Cys Leu Ser Cys Ser Lys Cys Arg 50 55 60Lys Glu Met Gly Gln Val Glu Ile Ser Ser Cys Thr Val Asp Arg Asp65 70 75 80Thr Val Cys Gly Cys Arg Lys Asn Gln Tyr Arg His Tyr Trp Ser Glu 85 90 95Asn Leu Phe Gln Cys Phe Asn Cys Ser Leu Cys Leu Asn Gly Thr Val 100 105 110His Leu Ser Cys Gln Glu Lys Gln Asn Thr Val Cys Thr Cys His Ala 115 120 125Gly Phe Phe Leu Arg Glu Asn Glu Cys Val Ser Cys Ser Asn Cys Lys 130 135 140Lys Ser Leu Glu Cys Thr Lys Leu Cys145 150 163 amino acids amino acid single linear protein not provided 5Thr Cys Arg Leu Arg Glu Tyr Tyr Asp Gln Thr Ala Gln Met Cys Cys1 5 10 15Ser Lys Cys Ser Pro Gly Gln His Ala Lys Val Phe Cys Thr Lys Thr 20 25 30Ser Asp Thr Val Cys Asp Ser Cys Glu Asp Ser Thr Tyr Thr Gln Leu 35 40 45Trp Asn Trp Val Pro Glu Cys Leu Ser Cys Gly Ser Arg Cys Ser Asp 50 55 60Asp Gln Val Glu Thr Gln Ala Cys Thr Arg Glu Gln Asn Arg Ile Cys65 70 75 80Thr Cys Arg Pro Gly Trp Tyr Cys Ala Leu Ser Lys Gln Glu Gly Cys 85 90 95Arg Leu Cys Ala Pro Leu Arg Lys Cys Arg Pro Gly Phe Gly Val Ala 100 105 110Arg Pro Gly Thr Glu Thr Ser Asp Val Val Cys Lys Pro Cys Ala Pro 115 120 125Gly Thr Phe Ser Asn Thr Thr Ser Ser Thr Asp Ile Cys Arg Pro His 130 135 140Gln Ile Cys Asn Val Val Ala Ile Pro Gly Asn Ala Ser Met Asp Ala145 150 155 160Val Cys Thr 159 amino acids amino acid single linear protein not provided 6Ala Cys Pro Thr Gly Leu Tyr Thr His Ser Gly Glu Cys Cys Lys Ala1 5 10 15Cys Asn Leu Gly Glu Gly Val Ala Gln Pro Cys Gly Ala Asn Gln Thr 20 25 30Val Cys Glu Pro Cys Leu Asp Ser Val Thr Ser Ser Asp Val Val Ser 35 40 45Ala Thr Glu Pro Cys Lys Pro Cys Thr Glu Cys Val Gly Leu Gln Ser 50 55 60Met Ser Ala Pro Cys Val Glu Ala Asp Asp Ala Val Cys Arg Cys Ala65 70 75 80Tyr Gly Tyr Tyr Gln Asp Glu Thr Thr Gly Arg Cys Glu Ala Cys Arg 85 90 95Val Cys Glu Ala Gly Ser Gly Leu Val Phe Ser Cys Gln Asp Lys Gln 100 105 110Asn Thr Val Cys Glu Glu Cys Pro Asp Gly Thr Tyr Ser Asp Glu Ala 115 120 125Asn His Val Asp Pro Cys Leu Pro Cys Thr Val Cys Glu Asp Thr Glu 130 135 140Arg Gln Leu Arg Glu Cys Thr Arg Trp Ala Asp Ala Glu Cys Glu145 150 155 162 amino acids amino acid single linear protein not provided 7Ala Cys Arg Glu Lys Gln Tyr Leu Ile Asn Ser Gln Cys Cys Ser Leu1 5 10 15Cys Gln Pro Gly Gln Lys Leu Val Ser Asp Cys Thr Glu Phe Thr Glu 20 25 30Thr Glu Cys Leu Pro Cys Gly Glu Ser Glu Phe Leu Asp Thr Trp Asn 35 40 45Arg Glu Thr His Cys His Gln His Lys Tyr Cys Asp Pro Asn Leu Gly 50 55 60Leu Arg Val Gln Gln Lys Gly Thr Ser Glu Thr Asp Thr Ile Cys Thr65 70 75 80Cys Glu Glu Gly Trp His Cys Thr Ser Glu Ala Cys Glu Ser Cys Val 85 90 95Leu His Arg Ser Cys Ser Pro Gly Phe Gly Val Lys Gln Ile Ala Thr 100 105 110Gly Val Ser Asp Thr Ile Cys Glu Pro Cys Pro Val Gly Phe Phe Ser 115 120 125Asn Val Ser Ser Ala Phe Glu Lys Cys His Pro Thr Ser Cys Glu Thr 130 135 140Lys Asp Leu Val Val Gln Gln Ala Gly Thr Asn Lys Thr Asp Val Val145 150 155 160Cys Gly 133 amino acids amino acid single linear protein not provided 8Asn Cys Val Lys Asp Thr Tyr Pro Ser Gly His Lys Cys Cys Arg Glu1 5 10 15Cys Gln Pro Gly His Gly Met Val Ser Arg Cys Asp His Thr Arg Asp 20 25 30Thr Val Cys His Asn Cys Val Lys Asp Thr Tyr Pro Ser Gly His Lys 35 40 45Cys Cys Arg Glu Cys Gln Pro Gly His Gly Met Val Ser Arg Cys Asp 50 55 60His Thr Arg Asp Thr Val Cys His Cys Arg Pro Gly Thr Gln Pro Arg65 70 75 80Gln Asp Ser Ser His Lys Phe Gly Val Asp Cys Val Pro Cys Pro Pro 85 90 95Gly His Phe Ser Pro Gly Ser Asn Gln Ala Cys Lys Pro Trp Thr Asn 100 105 110Cys Thr Leu Ser Gly Lys Gln Ile Arg His Pro Ala Ser Asn Ser Leu 115 120 125Asp Thr Val Cys Glu 130 45 amino acids amino acid single linear protein not provided 9Lys Ala Pro His Pro Lys Gln Glu Pro Gln Glu Ile Asn Phe Pro Asp1 5 10 15Asp Leu Pro Gly Ser Asn Thr Ala Ala Pro Val Gln Glu Thr Leu His 20 25 30Gly Cys Gln Pro Val Thr Gln Glu Asp Gly Lys Glu Ser 35 40 45 45 amino acids amino acid single linear protein not provided 10Lys Ala Pro His Pro Lys Gln Glu Pro Gln Glu Ile Asn Phe Pro Asp1 5 10 15Asp Leu Pro Gly Ser Asn Thr Ala Ala Pro Val Gln Glu Thr Leu His 20 25 30Gly Cys Gln Pro Val Thr Gln Glu Asp Gly Lys Glu Ser 35 40 45 45 amino acids amino acid single linear protein not provided 11Lys Ala Pro His Pro Lys Gln Glu Pro Gln Glu Ile Asn Phe Pro Asp1 5 10 15Asp Leu Pro Gly Ser Asn Thr Ala Ala Pro Val Gln Glu Thr Leu His 20 25 30Gly Cys Gln Pro Val Thr Gln Glu Asp Gly Lys Glu Ser 35 40 45

Claims

1. An isolated DNA which consists of a nucleotide sequence of bases 243 to 1199 of that shown in SEQ ID NO: 1.

2. An isolated DNA consisting of a nucleic acid sequence encoding for a Fas antigen which comprises an amino acid sequence from 1 to 157 of that shown in SEQ ID NO: 2 and is recognized by a mouse anti-Fas antibody having an activity to induce apoptosis in cells alone.

3. An isolated DNA coding for a Fas antigen which comprises an amino acid sequence selected from the group consisting of −16 to 319 and 1 to 319 of that shown in SEQ ID NO: 2.

4. An isolated DNA consisting of a nucleic acid sequence encoding for a polypeptide which comprises an amino acid sequence selected from the group consisting of −16 to 157, and 1 to 157, of that shown in SEQ ID NO: 2.

5. An isolated DNA which comprises a nucleotide sequence of bases 243 to 713, of that shown in SEQ ID NO: 1.

6. An expression vector which comprises a DNA of any one of claim 1, 2, 3, 4, or 5.

7. An expression vector which comprises a DNA of any one of claim 1, 2, 3, 4, or 5 and which further comprises a DNA which consists of a nucleotide sequence encoding for non-Fas peptide sequence.

8. The expression vector of claim 6, which further comprises a promotor derived from peptide chain elongation factor 1α (EF1α).

9. The expression vector of claim 7, which further comprises a promotor derived from peptide chain elongation factor 1α (EF1α).

10. An isolated cell transformed by an expression vector of claim 6.

11. An isolated cell transformed by an expression vector of claim 7.

12. An isolated cell transformed by an expression vector of any one of claim 8 or 9.

13. The cell according to claims 10 or 11, wherein said cell is a transformed eucaryotic cell.

14. The cell according to claim 13, wherein said cell is selected from the group consisting of a yeast cell and a mammalian cell.

15. The cell according to claims 10 or 11, wherein said cell is a transformed procaryotic cell.

16. The transformant according to claim 15, which is Escherichia coli.

17. A method of producing a Fas9 antigen, which comprises culturing a transformant transformed by a vector which comprises a DNA coding for a Fas antigen which consists of the amino acid sequence selected from the group consisting of amino acids −16 to 319 and 1 to 319 of that shown in SEQ ID NO: 2.

18. A method for producing a polypeptide which is part of Fas antigen, which comprises culturing a transformant transformed by a vector which comprises a DNA consisting of a nucleic acid sequence encoding for the amino acid sequence selected from the group consisting of amino acid sequences of amino acids −16 to 157, and 1 to 157, of that shown in SEQ ID NO: 2.