JP4406607B2 - Peptide and pharmaceutical containing the same - Google Patents

Description

  The present invention relates to a novel peptide effective as a cancer vaccine, a medicament for treatment and prevention of a tumor containing the peptide, and a novel diagnostic agent for hepatocellular carcinoma.

Primary hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Due to the global epidemic of hepatitis B and C, the incidence of HCC in Asia and European countries has increased rapidly (Schaffer, DF and Sorell, MF, Lancet 353, 1253-1257). (1999)), this trend is expected to continue over the next 50 years considering the long latency from HCC infection to onset. The prognosis of advanced HCC is poor and new treatment strategies are urgently needed.
On the other hand, recent advances in molecular biology and tumor immunology have identified a number of genes that encode tumor antigens and antigenic peptides recognized by tumor-responsive cytotoxic T lymphocytes (CTLs). The potential for antigen-specific tumor immunotherapy is increasing (Boon, T. and van der Bruggen, P., J. Exp. Med. 183, 725-729 (1996); Rosenberg, SA. , J. Natl. Cancer Inst. 88, 1635-1644 (1996)).
α-fetoprotein (AFP) is expressed only in embryonic periods in normal tissues, but expression has been reported to be reactivated in many HCCs (Fujiyama, S. et al., Oncology 62, 57-63). (2002)). Mouse and human T cell repertoires can also recognize AFP-derived peptide epitopes presented by MHC class I molecules (Butterfield, L. H. et al., Cancer Res. 59, 3134-3142; Jr Volmer, C. M. M. et al. Cancer Res. 59, 3064-3067 (1999); Butterfield, L. H. et al. J. Immunol. 166, 5300-5308 (2001)). Despite high plasma levels of exposure to this carcinoembryonic protein during fetal development, mature T cells do not acquire full tolerance to AFP and are AFP specific. T cells are detected in peripheral blood. That is, oncofetal proteins can be targets for immunotherapy. AFP and PIVKA-II (Fujiyama, S. et al., Oncology 62, 57-63 (2002)) are well-known tumor markers for HCC.
In addition, cDNA microarray technology is rapidly evolving that allows researchers to obtain comprehensive data on gene-expression profiles. Several studies have demonstrated that this technique is useful for the identification of novel cancer-related genes and the classification of human cancers at the molecular level (Gorub, TR, et al., Science 286, 531-537 (1999). Alizadeh, A. A. et al., Nature 403, 503-511 (2000); Ono, K. et al., Cancer Res. 60, 5007-5011 (2000); Kitahara, O. et al., Cancer Res. 61, 3544 -3549 (2001); Kihara, C. et al., Cancer Res. 61, 6474-6479 (2001)). We have previously reported the identification of genes whose expression changes during the development of HCC by using genome-wide cDNA microarrays containing 23,040 genes. Then, the expression profiles of these genes in 20 primary HCCs were examined (Okabe, H. et al., Cancer Res. 61, 1129-2137 (2001)).
In 1996, Philia et al. Reported that the glypican-3 (GPC3) gene encoding one member of the glypican family was mutated in patients with Simpson-Golabi-Behmel syndrome (SGBS) ( Piria, G. et al., Nat. Genet. 12, 241-247 (1996)). SGBS is an X-linked inherited disease characterized by pre- and post-natal overgrowth and a wide range of clinical symptoms ranging from very mild phenotypes in female carriers to lethal symptoms in male infants (Neri, G. et al., Am. J. Med. Genet. 79, 279-283 (1998)). The clinical features of SGBS include distinct facial appearance, cleft palate, joint finger, multifinger, adrenal milk, cystic and dysplastic kidneys, congenital heart defects and the like (Behmel, A. et al. Hum. Genet. 67, 409-413 (1984); Garganta, CL, and Bodurtha, JN, Am. J. Med. Genet. 44, 129-135 (1992); And Rosen, L., Am. J. Med. Genet. 17, 345-358 (1984); Gurieri, F. et al., Am. J. Med. Genet. 44, 136-137 (1992)). Most GPC3 mutations have been reported to be point mutations or deletions of small genes containing several exons (Hughes-Benzie, RM et al., Am. J. Med. Genet. 66, 227- Lindsay, S. et al., J. Med. Genet. 34, 480-483 (1997); Veugelers. M. et al., Hum. Mol. Genet. 9, 1321-1328 (2000); Y. et al., J. Med. Genet. 36, 57-58 (1999)). Also, since there is no correlation between patient phenotype and mutation location, SGBS may be caused by functional GPC3 protein deficiency and other genetic factors that produce phenotypic differences within and between families. (Hughes-Benzie, RM, et al., Am. J. Med. Genet. 66, 227-234 (1996)), and GPC3-deficient mouse studies also supported this hypothesis. (Cano-Gauci, DF et al., J. Cell Biol. 146, 255-264 (1999)). These mice have some of the abnormalities found in SGBS patients, including overgrowth, cystic and dysplastic kidneys.
Antigens that are specifically overexpressed in cancer and whose expression levels are negligible in various normal tissues may be ideal targets in immunotherapy. In such a case, CTL can be expected to show cytotoxicity only against cancers that overexpress the antigen and no side effects in normal tissues. Studies using Northern blot analysis have reported that GPC3 mRNA is overexpressed in HCC, placenta, fetal liver, fetal lung, and fetal kidney (Zhu, ZW et al., Gut 48, 558- 564 (2001); Hsu.HC et al., Cancer Res.57,5179-5184 (1997); Pellegrini, M. et al., Dev Dyn.213, 431-439 (1998)).
In addition, GPC3 has an inhibitory effect on cell proliferation and can induce apoptosis in certain tumor cells (Dunes Gonzales, A. et al., J. Cell Biol. 141, 1407-1414 (1998); Cano-Gauci). , DF et al., J. Cell Biol.146, 255-264 (1999)), there is a report that GPC3 expression is suppressed in tumors of various origins. Lin et al. Showed that GPC3 is expressed in normal ovaries but cannot be detected in certain ovarian cancer cell lines (Lin, H. et al., Cancer Res. 59, 807-810 (1999)). . In all cases where GPC3 expression was not observed, there was no mutation in the coding region, the GPC3 promoter was excessively methylated, and GPC3 expression was restored by treatment with a demethylating agent. Furthermore, ectopic expression of GPC3 has been reported to inhibit colony forming activity in several ovarian cancer cell lines. Other data associating GPC3 with cancer is from differential mRNA display studies between normal rat mesothelial cells and mesothelioma cell lines (Murthy, SS et al., Oncogene 19, 410-416 (2000)). In this study, GPC3 was found to be constantly repressed in tumor cell lines. Furthermore, similar expression suppression has been seen in cell lines derived from primary rat mesothelioma and human mesothelioma. Similar to ovarian cancer, no mutations have been found in the GPC3 coding sequence, but aberrant methylation is seen in the GPC3 promoter region in most cell lines. As reported (Duenas Gonzales, A. et al., J. Cell. Biol. 141, 1407-1414 (1998)), ectopic expression of GPC3 in mesothelioma cell lines inhibits colony-forming activity. It has been shown. More recently, Xiang et al. Reported that GPC3 is not expressed in human breast cancer (Xiang, YY, et al., Oncogene 20, 7408-7412 (2001)). These data suggest that GPC3 may act as a negative regulator of cell proliferation in these cancers. That is, GPC3 expression decreases during tumor progression in cancers arising from adult GPC3-positive tissues, and this decrease appears to play some role in the development of a malignant phenotype.
In contrast, in the case of HCC, tumors arise from liver tissue that expresses GPC3 only in the fetus, and GPC3 expression tends to reappear on transformation to malignancy. It is not clear whether GPC3 reexpression is important in the progression of these tumors. During the last few years it has become clear that cell surface heparan sulfate proteoglycans (HSPGs) are required for the expression of optimal activity of fibroblast growth factor (FGF) and heparin binding growth factors such as Wnt ( Yayon, A. et al., Cell 64, 841-848 (1991); Schlessinger, J. et al., Cell 83, 357-360 (1995)). Glypican is a family of GPI-anchored cell surface HSPGs, and this tissue-specific difference in the relationship between tumorigenesis and GPC3 expression levels regulates growth and survival factors in different ways for each tissue It is speculated that this is because of this. GPC3 appears to act as an oncofetal protein at least in these organs. In general, carcinoembryonic protein has not been shown to play an important role in tumor progression, but has been used as a tumor marker or immunotherapy target (Coggin, JH Jr., CRC Critical Reviews in Oncology). / Hematology 5, 37-55 (1992); Matsuura, H. and Hakomori S.-I., Proc. Natl. Acad, Sci. USA. 82, 6517-6521 (1985)). Whether the oncofetal behavior of GPC3 can be exploited for clinical use and whether this re-expression of glypican is important in the progression of HCC is further researched.
Despite the variety of treatment methods for HCC, the prognosis is poor compared to other cancers, making it one of the intractable cancers. The reason is that cirrhosis at the base of HCC, the liver function of the original patient is bad, and the fact that cancer occurs from another place even if one cancer is treated. There is an urgent need for new treatment strategies. If an immunotherapy targeting an antigen that is highly expressed specifically in HCC can be developed, it may be a therapeutic method that effectively eliminates only cancer without damaging its own normal organ. In addition, any terminal cancer patient can be a treatment that can be used for patients whose liver function is too poor to perform other treatments. In Japan, it is said that there are more than 2 million people with hepatitis C who are HCC reserve groups. Such immunotherapy may also be used to prevent HCC in these infected individuals. AFP and PIVKA-II are known as tumor markers for HCC, but may not be detected in some patients, or may be false positive in patients with benign liver disease cirrhosis or chronic hepatitis. Diagnosis is considered difficult. Other useful tumor markers are also needed for early diagnosis of HCC.

Based on the cDNA microarray interpretation data, the present inventors identified glypican 3 (GPC3) as a novel carcinoembryonic protein specifically overexpressed in human hepatocellular carcinoma, and targeted antigen for immunotherapy We have discovered novel peptides that can be potential candidates. Next, the present inventors detected soluble GPC3 protein in the serum of HCC patients, and revealed that GPC3 could be a new tumor marker for HCC.
That is, the present invention provides the following (1) to (18).
(1) A peptide comprising the amino acid sequence shown in any one of SEQ ID NOs: 5 to 16.
(2) A peptide having the ability to induce cytotoxic T cells, wherein one or two amino acids are substituted or added in the amino acid sequence shown in any of SEQ ID NOs: 5 to 16.
(3) The peptide according to (2) above, wherein the second amino acid from the N-terminus is phenylalanine, tyrosine, methionine or tryptophan.
(4) The peptide according to (2) or (3) above, wherein the C-terminal amino acid is phenylalanine, leucine, isoleucine, tryptophan or methionine.
(5) A medicament for treating and / or preventing a tumor, comprising at least one peptide according to any one of (1) to (4) above.
(6) An exosome presenting on the surface a complex containing the peptide according to any one of (1) to (4) above and an HLA molecule.
(7) The exosome according to (6) above, wherein the HLA molecule is HLA-A24.
(8) The exosome according to (7) above, wherein the HLA molecule is HLA-A ^* 2402.
(9) A method for inducing antigen-presenting cells having high cytotoxic T cell-inducing ability using the peptide according to any one of (1) to (4) above.
(10) A cell comprising introducing a gene encoding a glypican-3 (Glypican-3; GPC3) protein or a partial peptide thereof containing the peptide according to any one of (1) to (4) above into an antigen-presenting cell A method for inducing antigen-presenting cells having a high ability to induce cytotoxic T cells.
(11) A method for inducing cytotoxic T cells using the peptide according to any one of (1) to (4) above.
(12) An isolated cytotoxic T cell induced by using the peptide according to any one of (1) to (4) above.
(13) An antigen-presenting cell that presents a complex of an HLA molecule and the peptide according to any one of (1) to (4) above.
(14) The antigen-presenting cell according to (13), which is induced by the method according to (9) or (10).
(15) A diagnostic agent for hepatocellular carcinoma (HCC), comprising an antibody against GPC3.
(16) A method for diagnosing HCC, comprising contacting a sample with an antibody against GPC3.
(17) The method according to (16), further comprising quantifying GPC3 in the sample.
(18) A kit for diagnosis of HCC, comprising an antibody against GPC3.
This specification includes the contents described in the specification and / or drawings of Japanese Patent Application No. 2002-245831 which is the basis of the priority of the present application.

FIG. 1 shows HCC specific expression of GPC3 mRNA in adult tissues.
The relative ratio (RR) of human GPC3 mRNA expression in 20 HCC and various normal tissues is shown. The RR in HCC indicates the tumor: non-tumor intensity ratio in each case. RR in normal tissue indicates the strength ratio of each normal tissue: normal liver.
FIG. 2 shows the expression of GPC3 and β-actin (control) mRNA detected by RT-PCR in human HCC cell lines.
Lane 1: HepG2, Lane 2: Hep3B, Lane 3: PLC / PRF / 5, Lane 4: SK-Hep-1, Lane 5: HuH-7
FIG. 3 shows a result of examining PCTL stimulated with GPC3 peptide (peptide (pep) 1-12: SEQ ID NOs: 5 to 16) and further expanded for CTL activity using a 6-hour ⁵¹ Cr release assay. Indicates the part. The value on the vertical axis indicates the specific cell lysis rate (%) calculated based on the average value of three assays. Of ^{SK-Hep-1, HLA-} A24 - - HLA-A24 + GPC3 +++ of HepG2, ^HLA-A24 + GPC3 as HCC cell lines using ^{GPC3 +++} of Hep3B and HuH-7, a peptide 1,3 to a patient 1 , 7 or 12 induced CTL, patient 2 with CTL induced with peptide 5, 6, 10, or 11, patient 3 with CTL induced with peptide 2 or 12, patient 4 with peptide 1 CTL induced with 2, 3, 4, 7, or 10; CTL induced with peptide 1, 3, 4, 11, or 12 for patient 5; CTL induced with peptide 6 or 9 for patient 6 , CTL induced with peptide 4, 5, 6, 8, 9, 11, or 12 for patient 7, induced with peptide 5, 7, or 10 for patient 8 It was shown the results of the CTL. The horizontal axis represents the Effector / Target ratio (E / T ratio), that is, the ratio of the CTL number to the number of cancer cells.
FIG. 4 shows the presence of GPC3 protein in the culture supernatant of HepG2 using Western blot.
Lanes 1, 3, 5, and 7: 6, 12, 24, and 48 hours of incubation, 1 × 10 ⁵ lysates of HepG2 cells Lanes 2, 4, 6, and 8: 6, 12, 24, and 20 μl of HepG2 culture supernatant after 48 hours of culture
FIG. 5 shows the results of quantification by ELISA of GPC3 protein secreted into the culture supernatant of three types of HCC cell lines (Hep G2, Hep 3B and SK-Hep-1). The concentration of GPC3 protein in 1 ml of culture supernatant after 24 hours culture of 1 × 10 ⁵ HepG2 cells was defined as 1 U / ml.
FIG. 6 shows the detection of soluble GPC3 protein in HCC patient serum by Western blot.
FIG. 7 shows the results of ELISA quantification of GPC3 protein in the sera of 28 HCC patients and 54 healthy donors (HD). 1.71 is the upper limit of normal for soluble GPC3 protein in serum, defined as the mean value of GPC3 protein in serum from 54 HD + 3SD.

本発明は更に、配列番号５〜１６のいずれかに示すアミノ酸配列において１個または２個のアミノ酸が置換または付加されており、細胞傷害性Ｔ細胞の誘導能を有するペプチドも提供する。１個または２個のアミノ酸の置換または付加は、他のタンパク質のアミノ酸配列との一致がない限りにおいて、ＣＴＬ誘導能を有し得る。特に、アミノ酸の置換として、Ｎ末端から２番目のアミノ酸のフェニルアラニン、チロシン、メチオニンまたはトリプトファンへの置換、Ｃ末端のアミノ酸のフェニルアラニン、ロイシン、イソロイシン、トリプトファンまたはメチオニンへの置換は好適な例である。
上記の本発明のペプチドは、１種または２種以上の組み合わせとして、生体内でＣＴＬを誘導し得る癌ワクチンとして使用することができる。本発明のペプチドの投与により、抗原提示細胞のＨＬＡ分子に当該ペプチドが高密度に提示され、提示されたペプチドとＨＬＡ分子との複合体に対して特異的に反応するＣＴＬが誘導され、標的細胞となるべき肝細胞癌細胞に対する攻撃力が高まる。あるいは、被験者から樹状細胞を取り出して本発明のペプチドで刺激することにより、細胞表面に本発明のペプチドを負荷した抗原提示細胞が得られ、これを再度被験者に投与することで被験者においてＣＴＬを誘導し、標的細胞に対する攻撃力を高めることができる。
すなわち、本発明は、本発明のペプチドを１種以上含む、腫瘍の治療または腫瘍の増殖・転移等の予防のための医薬を提供するものである。尚、ｉｎ ｖｉｖｏ及びｉｎ ｖｉｔｒｏにおいて、本発明のペプチドによる抗原提示細胞の刺激は、細胞に対して高濃度のペプチドを存在させることによって、当該細胞に予め負荷されているペプチドとの交換が生じ、容易に行われる。このため、ＨＬＡ分子との結合親和性はある程度以上高いことが必要とされる。
本発明の医薬は、本発明のペプチドを単独で直接投与しても良いが、通常用いられる製剤学的方法によって製剤化した医薬組成物として投与しても良い。その場合、本発明のペプチドの他に、通常医薬に用いられる担体、賦形剤等を適宜含むことができ、特に限定されるものではない。
本発明のペプチドを有効成分とする肝細胞癌の治療及び／または予防のための医薬は、細胞性免疫が効果的に成立するようにアジュバントと共に投与したり、他の抗癌剤等の有効成分と共に投与したり、また粒子状の剤型にして投与することができる。アジュバントとしては、文献（Ｃｌｉｎ．Ｍｉｃｒｏｂｉｏｌ．Ｒｅｖ．，７：２７７−２８９，１９９４）に記載のものなどが応用可能である。また、リポソーム製剤、直径数μｍのビーズに結合させた粒子状の製剤、リピッドを結合させた製剤なども考えられる。投与方法としては、経口投与、皮内投与、皮下投与、静脈注射などが利用でき、全身投与、あるいは目的となる腫瘍の近傍に局所投与しても良い。本発明のペプチドの投与量は、治療すべき疾患、患者の年齢、体重、投与方法等により適宜調整することができるが、通常０．００１ｍｇ〜１０００ｍｇ、好ましくは０．００１ｍｇ〜１０００ｍｇ、より好ましくは０．１ｍｇ〜１０ｍｇであり、数日ないし数月に１回投与するのが好ましい。当業者であれば、適当な投与量を適宜選択することが可能である。
あるいはまた、本発明は、本発明のペプチドとＨＬＡ分子との複合体を表面に提示している、エキソソームと呼ばれる細胞内小胞を提供する。エキソソームの調製は、例えば特表平１１−５１０５０７号、及び特表２０００−５１２１６１号に詳細に記載されている方法を用いて行うことができるが、好ましくは治療及び／または予防の対象となる被験者から得た抗原提示細胞を用いて調製する。本発明のエキソソームは、上記本発明のペプチドと同様に癌ワクチンとして接種することができる。
ＨＬＡ分子としては、治療及び／または予防を必要とする被験者のＨＬＡ分子と同じ型のものであることが必要である。例えば、日本人の場合にはＨＬＡ−Ａ２４、特にＨＬＡ−Ａ^＊２４０２とすると好適であることが多い。
本発明はまた、本発明のペプチドを用いた抗原提示細胞の誘導方法も提供する。樹状細胞を末梢血単球から誘導した後、ｉｎ ｖｉｔｒｏまたはｉｎ ｖｉｖｏで本発明のペプチドと接触（刺激）させ、抗原提示細胞を誘導することができる。本発明のペプチドを被験者に投与した場合、被験者の体内で本発明のペプチドを負荷した抗原提示細胞が誘導される。あるいは、抗原提示細胞に本発明のペプチドをｉｎ ｖｉｔｒｏで負荷した後に被験者にワクチンとして投与することもできる。
本発明はまた、ＧＰＣ３タンパク質または上記本発明のペプチドを含む、その部分ペプチドをコードする遺伝子をｉｎ ｖｉｔｒｏで抗原提示細胞に導入することを含む、細胞傷害性Ｔ細胞誘導能の高い抗原提示細胞を誘導する方法を提供する。導入する遺伝子はＤＮＡの形態であってもＲＮＡの形態であっても良い。導入の方法は当分野において通常行われるリポフェクション、エレクトロポレーション、リン酸カルシウム法等の種々の方法を用いれば良く、特に限定するものではない。具体的には、例えばＣａｎｃｅｒ Ｒｅｓ．，５６：５６７２，１９９６；Ｊ．Ｉｍｍｕｎｏｌ．，１６１：５６０７，１９９８；Ｊ．Ｅｘｐ．Ｍｅｄ．，１８４：４６５，１９９６；特表２０００−５０９２８１号に記載のようにして行うことができる。遺伝子を抗原提示細胞に導入することによって、当該遺伝子は細胞中で転写、翻訳等の処理の後、得られたタンパク質がＨＬＡクラスＩまたはクラスＩＩのプロセッシング及び提示経路を経て、部分ペプチドが提示される。
本発明は更に、上記本発明のペプチドを用いてＣＴＬを誘導する方法を提供する。本発明のペプチドを被験者に投与した場合、被験者の体内でＣＴＬが誘導され、肝細胞癌細胞を標的とした免疫力が増強される。あるいは、被験者由来の抗原提示細胞及びＣＤ８陽性細胞、または末梢血単核球をｉｎ ｖｉｔｒｏで本発明のペプチドと接触（刺激）させ、ＣＴＬを誘導してから被験者にもどすｅｘ ｖｉｖｏの治療方法にも用いることができる。
本発明は更に、本発明のペプチドを用いて誘導される、単離された細胞傷害性Ｔ細胞を提供する。本発明のペプチドを提示した抗原提示細胞による刺激に基づいて誘導された細胞傷害性Ｔ細胞は、好ましくは治療及び／または予防の対象である被験者由来のものであり、単独、または、本発明のペプチド、エキソソーム等を含む、他の医薬と共に抗腫瘍効果を目的として投与することができる。
本発明は更に、ＨＬＡ分子と本発明のペプチドとの複合体を提示する抗原提示細胞を提供する。本発明のペプチド、あるいは本発明のペプチドを含むＧＰＣ３タンパク質、またはその部分ペプチドをコードする遺伝子との接触によって得られる当該抗原提示細胞は、好ましくは治療及び／または予防の対象である被験者由来のものであり、単独、または、本発明のペプチド、エキソソーム、細胞傷害性Ｔ細胞等を含む、他の医薬と共にワクチンとして投与することができる。
本発明は更に、ＧＰＣ３に対する抗体を含む、肝細胞癌の診断剤を提供する。ＧＰＣ３に対する抗体は、ポリクローナルまたはモノクローナル抗体のいずれでも良く、当業者に公知の方法（例えば、「新生化学実験講座１，タンパク質Ｉ，３８９−４０６，東京化学同人」参照）により調製することが可能である。ＧＰＣ３タンパク質はアミノ酸配列が前記のように公知であり、当該アミノ酸配列に基づいて通常のタンパク質発現技術を用いて製造でき、また市販のもの（Ｓａｎｔａ Ｃｒｕｚ，ＣＡ）を利用することも可能である。市販のＧＰＣ３を用いる場合は、必要に応じてＳＤＳ−ｏｕｔ^ＴＭ（Ｓｏｄｉｕｍ Ｄｏｄｅｃｙｌ Ｓｕｌｆａｔｅ Ｐｒｅｃｉｐｉｔａｔｉｏｎ Ｒｅａｇｅｎｔ；ＰＩＥＲＣＥ，Ｒｏｃｋｆｏｒｄ，ＩＬより購入）を用いてＳＤＳを除いて使用することが好ましい。またＧＰＣ３の部分ペプチドは、ＧＰＣ３のアミノ酸配列から適当な部分配列を選択し、通常のペプチド合成技術を用いて製造できる。
ポリクローナル抗体の調製は、まず、例えば、ウサギ、モルモット、マウス、ラット、ハムスター、ニワトリ、サルなどの動物にＧＰＣ３タンパク質またはその部分ペプチドを感作抗原として投与する。投与は、抗体産生を促進するアジュバント（ＦＩＡやＦＣＡ）と共に行ってもよい。投与は、通常、数週間ごとに行う。免疫を複数回行うことにより、抗体価を上昇させることができる。最終免疫後、免疫動物から採血を行うことにより抗血清が得られる。この抗血清に対し、例えば、硫酸アンモニウム沈殿や陰イオンクロマトグラフィーによる分画、プロテインＡや固定化抗原を用いたアフィニティー精製を行うことにより、ポリクローナル抗体を調製することができる。
一方、モノクローナル抗体の調製は、例えば、ＧＰＣ３タンパク質もしくはその部分ペプチドを、上記と同様に動物に免疫し、最終免疫後、この免疫動物から脾臓またはリンパ節を採取する。この脾臓またはリンパ節に含まれる抗体産生細胞とミエローマ細胞とをポリエチレングリコールなどを用いて融合し、ハイブリドーマを調製する。細胞融合は、基本的には公知の方法、たとえば、ケーラーとミルステインらの方法（Ｋｏｈｌｅｒ．Ｇ．ａｎｄ Ｍｉｌｓｔｅｉｎ，Ｃ．、Ｍｅｔｈｏｄｓ Ｅｎｚｙｍｏｌ．（１９８１）７３，３−４６）等に準じて行うことができる。得られたハイブリドーマは、通常の選択培養液、例えばＨＡＴ培養液（ヒポキサンチン、アミノプテリンおよびチミジンを含む培養液）で培養することにより選択される。上記ＨＡＴ培養液での培養は、目的とするハイブリドーマ以外の細胞（非融合細胞）が死滅するのに十分な時間継続する。次いで、目的のハイブリドーマをスクリーニングし、これを培養し、その培養上清からモノクローナル抗体を調製することができる。
また、本発明の抗体は、遺伝子工学的手法により抗体遺伝子を含む発現ベクターで形質転換した宿主に産生させても良い。例えば、モノクローナル抗体として、抗体遺伝子をハイブリドーマからクローニングし、適当なベクターに組み込んで、これを宿主に導入し、遺伝子組換え技術を用いて産生させた組換え型のものを用いることができる（例えば、Ｖａｎｄａｍｍｅ，Ａ．Ｍ．ｅｔ ａｌ．，Ｅｕｒ．Ｊ．Ｂｉｏｃｈｅｍ．（１９９０）１９２，７６７−７７５，１９９０参照）。
本発明で使用される抗体の製造のために、任意の発現系、例えば真核細胞又は原核細胞系を使用することができる。真核細胞としては、例えば樹立された哺乳類細胞系、昆虫細胞系、真糸状菌細胞および酵母細胞などの動物細胞等が挙げられ、原核細胞としては、例えば大腸菌細胞等の細菌細胞が挙げられる。次に、形質転換させた宿主細胞をｉｎ ｖｉｔｒｏまたはｉｎ ｖｉｖｏで培養して目的とする抗体を産生させる。宿主細胞の培養は公知の方法に従い行う。
モノクローナル抗体の精製は、例えば、硫酸アンモニウム沈殿や陰イオンクロマトグラフィーによる分画、プロテインＡや固定化抗原を用いたアフィニティークロマトグラフィーによる精製により行うことができる。その他、通常のタンパク質で使用されている分離、精製方法を使用すればよく、例えば、上記アフィニティーカラム以外のクロマトグラフィーカラム、フィルター、限外濾過、塩析、透析等を適宜選択、組み合わせることにより、抗体を分離、精製することができる。
本発明で使用される抗体は、抗体の全体分子に限られずＧＰＣ３に結合する限り、抗体の断片又はその修飾物であってもよく、二価抗体も一価抗体も含まれる。例えば、抗体の断片としては、Ｆａｂ、Ｆ（ａｂ’）２、Ｆｖ、１個のＦａｂと完全なＦｃを有するＦａｂ／ｃ、またはＨ鎖若しくはＬ鎖のＦｖを適当なリンカーで連結させた単鎖Ｆｖ（ｓｃＦｖ）が挙げられる。尚、本発明の目的のためには、抗体はＧＰＣ３のいかなるエピトープを認識するものであっても良い。
診断剤としての正確性のためには、抗体はヒト型抗体もしくはヒト抗体であることが好ましい。ヒト型抗体は、例えば、マウス−ヒトキメラ抗体であれば、ＧＰＣ３タンパク質に対する抗体を産生するマウス細胞から抗体遺伝子を単離し、そのＨ鎖定常部をヒトＩｇＥ Ｈ鎖定常部遺伝子に組換え、マウス骨髄腫細胞に導入することにより調製できる。また、ヒト抗体は、免疫グロブリン遺伝子をヒトと入れ換えたマウスにＧＰＣ３タンパク質を免疫することにより調製することが可能である。
本発明の診断剤において、限定するものではないが、抗体は例えば１μｇ／ｍｌの濃度で用いることができる。診断剤には上記ＧＰＣ３に対する抗体の他に、必要に応じて薬学的に許容される担体等を適宜含有させることができる。
本発明は更に、サンプルとＧＰＣ３に対する抗体を接触させることを含む、肝細胞癌の診断方法を提供する。診断方法は、更にサンプル中のＧＰＣ３を定量することを含み得る。本発明において、サンプルは、ＨＣＣに罹患しているおそれのある被験者から得られる血清、唾液、尿等が挙げられるが、特に好ましくは血清である。サンプルと上記抗体との接触は、当分野において通常行われている方法に基づいて行えば良く、特に限定するものではない。診断は、例えばサンプルと上記抗体との接触の後、サンプル中に存在し得るＧＰＣ３と抗体との特異的結合を、蛍光物質や発光物質、酵素等で標識した二次抗体等を使用して定量的に検出することにより行うことができる。また、診断のための反応をウェル等の液相中で行っても良く、あるいはＧＰＣ３に対する抗体を固定した固相支持体上で行っても良い。この場合、ＨＣＣに罹患していない正常なサンプル、あるいはＨＣＣであることが判明しているサンプルを用いて予め作製した標準値と比較することによって、測定された値がＨＣＣ陽性であるか否かを判定することができる。また、診断の際には、多数のＨＣＣ患者と健常入の血清中ＧＰＣ３量を測定して、カットオフ値を設定することが好ましい。
本発明の診断方法は、ＨＣＣに罹患しているか否かの診断に用いることができる他、ＨＣＣに対する治療の効果を確認するために経時的に行うこともできる。
更に本発明は、ＧＰＣ３に対する抗体を含む、ＨＣＣの診断のためのキットを提供する。当該キットには、ＧＰＣ３に対する抗体の他、二次抗体、定量のための標準サンプル、バッファー等を含めることができる。
以下、実施例を挙げて本発明を更に説明するが、本発明はこれら実施例に限定されるものではない。
［実施例１］ ＨＣＣで特異的に過剰発現するＧＰＣ３遺伝子の同定
ｃＤＮＡマイクロアレイによる遺伝子発現のプロファイリングは先に報告したように行った（Ｏｋａｂｅ，Ｈ．ら，Ｃａｎｃｅｒ Ｒｅｓ．６１，２１２９−２１３７（２００１））。肝切除術を行った２０名の患者から、原発性ＨＣＣ及び対応する非癌性肝臓組織を得た。そのうち１０例はＢ型肝炎表面抗原陽性、１０例はＣ型肝炎ウイルス（ＨＣＶ）陽性であり、ＨＢＶ及びＨＣＶの双方に感染している例はなかった。ＨＢＶ陽性及びＨＣＶ陽性のもので、年齢、性別、分化の程度、血管の浸潤、腫瘍の段階に関して有意な差異はなかった。Ｎａｔｉｏｎａｌ Ｃｅｎｔｅｒ ｆｏｒ Ｂｉｏｔｅｃｈｎｏｌｏｇｙ ＩｎｆｏｒｍａｔｉｏｎのＵｎｉＧｅｎｅデータベースから選択した２３，０４０種のｃＤＮＡを含む「ゲノムワイドの」ｃＤＮＡマイクロアレイを作製した。ＨＣＣ及び対応する非癌性肝臓組織間での発現プロファイルを比較してＨＣＣにおいて特異的に過剰発現している遺伝子を探索し、その結果、ＨＣＣ患者に対する免疫治療の候補であり、おそらくは理想的な標的であり得るＧＰＣ３を同定した。２０例のＨＣＣ中１６例において、癌組織におけるＧＰＣ３ ｍＲＮＡの発現は非癌性組織における発現よりも５倍以上高かった（図１）。すなわち、ＧＰＣ３はほとんどのＨＣＣにおいて過剰発現しており、Ｂ型肝炎ウイルス（ＨＢＶ）またはＨＣＶ感染とは関連していなかった。一方、ＧＰＣ３ ｍＲＮＡは胎盤、胎児肝臓、胎児肺、及び胎児腎臓において高発現しており、成人の正常組織のほとんどで発現が低かった（図１）。これらのＧＰＣ３に関するデータは、ノーザンブロッティング研究に基づいて公表されているものと一致した（Ｚｈｕ，Ｚ．Ｗ．ら，Ｇｕｔ ４８，５５８−５６４（２００１）；Ｈｓｕ．Ｈ．Ｃ．ら，Ｃａｎｃｅｒ Ｒｅｓ．５７，５１７９−５１８４（１９９７）；Ｐｅｌｌｅｇｒｉｎｉ，Ｍ．ら，Ｄｅｖ Ｄｙｎ．２１３，４３１−４３９（１９９８））。この結果から、ＧＰＣ３はα−フェトタンパク質（ＡＦＰ）と同様に、ＨＣＣにおける新規な癌胎児性抗原であることが明らかとなった。
［実施例２］ ヒトＨＣＣ細胞系におけるＧＰＣ３ ｍＲＮＡ及びＨＬＡ−Ａ２４の発現
ＣＴＬアッセイのための標的ＨＣＣ細胞系を選択するために、逆転写−ＰＣＲ（ＲＴ−ＰＣＲ）を用いたＧＰＣ３ ｍＲＮＡ発現、抗ＨＬＡクラスＩ（ｗ６／３２、ＩｇＧ２ａ）または抗ＨＬＡ−Ａ２４（ＩｇＧ２）モノクローナル抗体（ＶＥＲＩＴＡＳ、東京）、及びＦＩＴＣコンジュゲートヤギ抗マウスＩｇＧ（ＩＣＮ／ＣＡＰＰＥＬ、Ａｕｒｏｒａ、ＯＨ）を用いた免疫染色及びフローサイトメトリーによるＨＬＡ−クラスＩ及び−Ａ２４の発現を検討した。ＨＣＣ細胞系であるＨｅｐ Ｇ２、Ｈｅｐ ３Ｂ、ＰＬＣ／ＰＲＦ／５、及びＨｕＨ−７は東北大学加齢医学研究所医用細胞資源センターから入手した。またＳＫ−Ｈｅｐ−１は久留米大学のＫ．Ｉｔｏｈ博士よりご供与頂いた。
ＲＴ−ＰＣＲは公知の方法（例えばＮａｋａｔｓｕｒａ，Ｔ．ら，Ｂｉｏｃｈｅｍ．Ｂｉｏｐｈｙｓ．Ｒｅｓ．Ｃｏｍｍｕｎ．２８１，９３６−９４４（２００１））に従って行った。９３９ｂｐの断片を増幅するＧＰＣ３遺伝子特異的ＰＣＲプライマーを設計し、これを用いて９４℃、５分の初期変性、及び５８℃のアニーリング温度での３０増幅サイクルからなるＲＴ−ＰＣＲ反応を行った。用いたＧＰＣ３ＰＣＲプライマー配列は、

対照であるβ−アクチンｍＲＮＡによる標準化の後、ＨＣＣ細胞系におけるＧＰＣ３ ｍＲＮＡの発現を比較した。
その結果、ＨｅｐＧ２、Ｈｅｐ３Ｂ、及びＨｕＨ−７ ＨＣＣ細胞系においてＧＰＣ３ ｍＲＮＡの強い発現が示され、ＰＬＣ／ＰＲＦ／５細胞系において中程度の発現が示されたが、ＳＫ−Ｈｅｐ−１ではそのような発現は見られなかった（図２）。尚、ＨｅｐＧ２及びＳＫ−Ｈｅｐ−１はＨＬＡ−Ａ２４を発現したが、Ｈｅｐ３Ｂ及びＨｕＨ−７は発現しなかった。
［実施例３］ 末梢血単核球（ＰＢＭＣ）の刺激による腫瘍応答性ＣＴＬの誘導
先行技術（Ｋｕｂｏ，Ｒ．Ｔ．ら，Ｊ．Ｉｍｍｕｎｏｌ．１５２，３９１３−３９２４（１９９４））に基づいて、ＨＬＡ−Ａ２４分子に結合することが予想されるＧＰＣ３由来ペプチドを探索し、１２種の異なるペプチドを合成して使用した（表１）。これらのペプチドは、Ｆｍｏｃ／ＰｙＢＯＰ法を用いて合成したものであり（後記参考例１〜１２を参照のこと）、ｂｉｏｌｏｇｉｃａ（東京）から購入した。ペプチドの純度は、ＨＰＬＣでいずれも９５％を越えることが確認された。

インフォームドコンセントを得た後、熊本大学医学部外科学第二講座において治療中のＨＬＡ−Ａ２４^＋ＨＣＣ患者から血液サンプル３０ｍｌを得、先に報告したように（Ｎａｋａｔｓｕｒａ，Ｔ．ら，Ｅｕｒ．Ｊ．Ｉｍｍｕｎｏｌ．３２，８２６−８３６（２００２））、Ｆｉｃｏｌｌ−Ｃｏｎｒａｙ密度勾配遠心法によってＰＢＭＣを単離した。ＨＬＡ−Ａ２４結合モチーフを有するｇｌｙｐｉｃａｎ−３由来のペプチド１２種（表１、Ｎｏ．１〜１２：配列番号５〜１６に対応）について、８名のＨＬＡ−Ａ２４^＋ＨＣＣ患者（Ｐｔ１〜８）から得たＰＢＭＣからＨＬＡ−Ａ２４拘束性で、かつ腫瘍応答性のＣＴＬを誘導する能力について検討した（図３、表１）。ＰＢＭＣからペプチド特異的ＣＴＬを誘導する方法は、先に報告した方法（Ｎａｋａｔｓｕｒａ，Ｔ．ら，Ｅｕｒ．Ｊ．Ｉｍｍｕｎｏｌ．３２，８２６−８３６（２００２））を用いた。ＣＴＬの表面表現型はＦＩＴＣ−コンジュゲート抗−ＣＤ３、−ＣＤ４、または−ＣＤ８モノクローナル抗体（ニチレイ、東京）を用いた直接免疫蛍光染色によって検討した。エフェクター細胞及びＨＬＡ拘束性を決定するために、培養開始時に各２０μｇ／ｍｌの抗−ＨＬＡ−クラスＩ（Ｗ６／３２、ＩｇＧ２ａ）、抗−ＨＬＡ−Ａ２４（００４１ＨＡ、ＩｇＧ２ａ）、抗−ＣＤ８（Ｎｕ−Ｔｓ／ｃ、ＩｇＧ２ａ）、抗−ＨＬＡ−ＤＲ（Ｈ−ＤＲ−１、ＩｇＧ２ａ）、及び抗−ＣＤ４（Ｎｕ−Ｔｈ／Ｉ、ＩｇＧ１）モノクローナル抗体を添加した。アイソタイプが合った対照として、抗−ＣＤ１３（ＭＣＳ−２、ＩｇＧ２ａ）及び抗−ＣＤ１４（ＪＭＬ−Ｈ１４、ＩｇＧ１）モノクローナル抗体を使用した。３〜４週間後、これらのＣＴＬ株の数はＰＢＭＣの培養前の数と比較して約１０倍に増加した。次にこれらのＣＴＬ株のＨＣＣ細胞株に対する細胞傷害活性を６時間の^５１Ｃｒ放出アッセイによって検討した。結果を図３及び表１に示す。９６種中３３種（３４．４％）のＣＴＬ株が、ＨＬＡ−Ａ２４⁻ＧＰＣ３^＋のＨｅｐ３Ｂ及びＨｕＨ−７、及びＨＬＡ−Ａ２４^＋ＧＰＣ３⁻のＳＫ−Ｈｅｐ−１に対してよりも、ＨＬＡ−Ａ２４^＋ＧＰＣ３^＋のＨｅｐＧ２に対して強い細胞傷害性を示した。この細胞傷害性はペプチド特異性を示し、抗−ＨＬＡ−クラスＩ、抗−ＣＤ８または抗−ＨＬＡ−Ａ２４モノクローナル抗体によって阻害されることから、これらのＴ細胞応答がＨＬＡ−Ａ２４拘束性のＣＤ８^＋ＣＴＬによって担われていることが示される。各ペプチドまたは各患者におけるＣＴＬの誘導率を表１に示す。これらの結果から、ＧＰＣ３由来の１２種のペプチドの全てがＣＴＬ誘導能を有し、ＨＬＡ−Ａ２４拘束性のＧＰＣ３由来ペプチド特異的ＣＤ８^＋ＣＴＬ株が８名のＨＣＣ患者の全員において誘導されたことが示される。
［実施例４］ ＨＣＣにおけるＧＰＣ３タンパク質の発現
４名のＨＣＣ患者から切除した肝臓組織周辺のＨＣＣ及び非癌性領域におけるＧＰＣ３のウエスタンブロッティング解析及び免疫組織化学分析を行った。
ウエスタンブロッティングは以下のように行った。サンプルを適量の溶解用バッファー（１５０ｍＭ ＮａＣｌ、５０ｍＭ Ｔｒｉｓ、ｐＨ７．４、１％Ｎｏｎｉｄｅｔ Ｐ−４０、１ｍＭオルトバナジウム酸ナトリウム（和光純薬工業（株））、１ｍＭ ＥＤＴＡ、及びプロテアーゼ阻害剤タブレット（Ａｍｅｒｓｈａｍ，Ａｒｌｉｎｇｔｏｎ Ｈｅｉｇｈｔｓ，ＩＬ））中で溶解した。溶解物の上清をＳＤＳ−ＰＡＧＥゲル上で電気泳動し、ニトロセルロース膜（Ｂｉｏ−Ｒａｄ，Ｈｅｒｃｕｌｅｓ，ＣＡ）にトランスファーした。５％脱脂乳、０．２％Ｔｗｅｅｎ２０を含有するＴｒｉｓ緩衝生理食塩水中でブロッキングした後、この膜を、ＧＰＣ３ ３０３−４６４のアミノ酸に対応する組換えタンパク質に対して作製された抗−ＧＰＣ３ウサギポリクローナル抗体（Ｓａｎｔａ Ｃｒｕｚ，Ｃａｌｉｆｏｒｎｉａ）と共にインキュベートし、ＰＢＳでよく洗浄し、ペルオキシダーゼコンジュゲート抗−ウサギＩｇ、西洋ワサビペルオキシダーゼ結合Ｆ（ａｂ’）_２断片（ロバ由来）（Ａｍｅｒｓｈａｍ）を用い、ＥＣＬキット（Ａｍｅｒｃｈａｍ）を使用して化学発光検出を行った。
免疫組織化学分析は、当分野において公知の方法に従って行った（Ｎａｋａｔｓｕｒａ，Ｔ．ら，Ｂｉｏｃｈｅｍ．Ｂｉｏｐｈｙｓ．Ｒｅｓ．Ｃｏｍｍｕｎ．２８１，９３６−９４４（２００１））。ＯＣＴ包埋用化合物に包埋した厚さ４μｍの組織サンプル切片を１：２００に希釈した抗−ＧＰＣ３抗体と共に染色した。陽性対照のために４５ｋＤａタグ付き融合タンパク質として大腸菌から産生されるＧＰＣ３ ３０３−４６４（Ｓａｎｔａ Ｃｒｕｚ，ＣＡ）及び抗−ｇｌｙｐｉｃａｎ−３ウサギポリクローナル抗体のビオチン化のためにＦｌｕｏＲｅｐｏｒｔｅｒ Ｍｉｎｉ−Ｂｉｏｔｉｎ−ＸＸ Ｐｒｏｔｅｉｎ Ｌａｂｅｌｉｎｇ Ｋｉｔ（Ｆ−６３４７）（Ｍｏｌｅｃｕｌａｒ Ｐｒｏｂｅｓ，Ｉｎｃ．，Ｅｕｇｅｎｅ）を使用した。９６ウェルのＥＬＩＳＡプレート（Ｎｕｎｃ，Ｄｅｎｍａｒｋ）を４℃で一晩、ＰＢＳ、ｐＨ７．４中０．１μｇ／ウェルの抗−ヒトＧＰＣ３ ３０３−４６４（Ｓａｎｔａ Ｃｒｕｚ）でコートした。次いで、４％ウシ血清アルブミン／ＰＢＳを用い、室温で１時間、プレートをブロッキングした。陽性対照の標準サンプル及び培養上清をビオチン化抗−ＧＰＣ３抗体と共に添加し、室温で２時間インキュベーションした。ＰＢＳで３回洗浄した後、各ウェルにＨＲＰ−コンジュゲートストレプトアビジン（ＥＮＤＯＧＥＮ，Ｗｏｂｕｒｎ）を添加した。３０分のインキュベーションの後、プレートをＰＢＳで３回洗浄し、ＴＭＢ基質溶液（ＥＮＤＯＧＥＮ）を添加した。解析のためにＥＬＩＳＡリーダー（モデル５５０、Ｂｉｏ−Ｒａｄ）を４０５ｎｍで用いた。
インフォームドコンセントを得た後、熊本大学医学部外科学第二講座において治療中のＨＣＣ患者から組織サンプルを得た。４種の腫瘍全てにおいて、ＧＰＣ３タンパク質の発現がＨＣＣ細胞において非癌性肝細胞と同程度に低いという同様の結果が得られた。従って、ＨＣＣ細胞中におけるＧＰＣ３ ｍＲＮＡ発現とＧＰＣ３タンパク質発現の間に矛盾が生じる。ＧＰＣ３はＧＰＩ−アンカー型膜タンパク質であり、分泌タンパク質である可能性が報告されている（Ｆｉｌｍｕｓ Ｊ．，Ｇｌｙｃｏｂｉｏｌｏｇｙ １１，１９Ｒ−２３Ｒ（２００１））。そこで、次に分泌されたＧＰＣ３タンパク質の検出を試みた。
［実施例５］ ＨＣＣ細胞株の培養上清及びＨＣＣ患者血清中における可溶性ＧＰＣ３タンパク質の検出
ＨｅｐＧ２の培養上清中に可溶性ＧＰＣ３タンパク質が存在するか否かを検討するために、所定の培養期間の後に回収したＨｅｐＧ２細胞溶解物及び培養上清についてウエスタンブロッティングを行った。無血清培地における６、１２、２４、及び４８時間の培養後に１×１０^５個のＨｅｐＧ２細胞から調製した細胞溶解物は、同様の量の６０ｋＤａのＧＰＣ３タンパク質の存在を示した（図４のレーン１、３、５、及び７）。一方、６、１２、２４、及び４８時間の培養後のＨｅｐＧ２培養上清（１ｍｌ／ウェルの２０μｌ）では６０ｋＤａのＧＰＣ３タンパク質が漸増しており、ＧＰＣ３タンパク質がＨｅｐＧ２から培養上清中に分泌されたことを示した。
次いで、抗−ＧＰＣ３ ３０３−４６４抗体及びビオチン化抗−ＧＰＣ３抗体を用いて酵素結合免疫吸着検査法（ＥＬＩＳＡ）による検出を行った。ＧＰＣ３ ３０３−４６４に対応する市販の組換えタンパク質を用い、ＥＬＩＳＡ系におけるＧＰＣ３の定量の精度を確認した。ＨｅｐＧ２培養上清の連続希釈を用い、ＯＤデータに基づいてＧＰＣ３タンパク質を定量する標準曲線を評価した。１×１０^５個のＨｅｐＧ２細胞を２４時間培養した後の培養上清１ｍｌ中のＧＰＣ３タンパク質の濃度を１Ｕ／ｍｌと定義した。ＨｅｐＧ２培養上清中のＧＰＣ３タンパク質の量はＨｅｐ３Ｂよりはるかに多く、一方ＳＫ−Ｈｅｐ−１においては検出できなかった（図５）。
次に、ＨＣＣ患者血清中の可溶性ＧＰＣ３タンパク質の検出を行った（図６）。２８名のＨＣＣ患者から血液サンプルを採取し、医療記録から患者のプロファイルを集めてＵＩＣＣ ＴＮＭ分類に基づいて臨床段階を決定した。患者７（Ｐｔ７、図６のレーン３）の血清２０μｌ中に６０ｋＤａのＧＰＣ３タンパク質のバンドが検出されたが、他の２名のＨＣＣ患者及び４名の健康なドナーの血清からは検出されなかった。次に２８名のＨＣＣ患者及び５４名の健康なドナー（ＨＤ）の血清中のＧＰＣ３タンパク質の量をＥＬＩＳＡによって評価した（図７）。５４名のＨＤ血清中のＧＰＣ３タンパク質の平均は０．７５Ｕ／ｍｌであり、標準偏差（ＳＤ）は０．３２であった。男女間で発現に差はなく、従って卵巣でのＧＰＣ３の弱い発現は、この系に関して無視できると考えられた。２８名のＨＣＣ患者の平均値は１．９８Ｕ／ｍｌであった。血清中のＧＰＣ３タンパク質の正常上限値を決定するために、５４名のＨＤ血清のＧＰＣ３タンパク質の平均＋３ＳＤとして１．７１を規定した。ＨＣＣ患者の３５．７％（１０／２８）、ＨＤの０％（０／５４）がＧＰＣ３タンパク質陽性（＞１．７１）であった。ＨＣＣ患者血清中のＧＰＣ３タンパク質の濃度は、ＨＤにおける濃度よりも有意に高かった（Ｐ＜０．０００１）。患者４、５及び７についてＥＬＩＳＡで評価したＧＰＣ３の濃度は、図６に示すようにそれぞれ０．９４、１．７３、及び６９．４Ｕ／ｍｌであった（表２）。すなわち、ウエスタンブロッティングでは６９．４Ｕ／ｍｌのＧＰＣ３タンパク質は検出できるが、１．７３Ｕ／ｍｌのＧＰＣ３は検出できなかった。
表２の結果から明らかなように、１０名のＧＰＣ３−陽性患者のうち２名（患者６及び２５）はＡＦＰ及びＰＩＶＫＡ−ＩＩの双方が陰性であり、その一方の患者（患者６）は比較的初期のＵＩＣＣステージＩＩとして分類された。すなわち、ＡＦＰ及びＰＩＶＫＡ−ＩＩの双方が陰性の患者においてＧＰＣ３が陽性となる場合があることから、ＧＰＣ３はＨＣＣの新規な腫瘍マーカーとして有用であることが明らかとなった。

［参考例１］ Ｓｅｒ−Ｐｈｅ−Ｐｈｅ−Ｇｌｎ−Ａｒｇ−Ｌｅｕ−Ｇｌｎ−Ｐｒｏ−Ｇｌｙ−Ｌｅｕ（配列番号５）の合成
開始レジンとしてＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎ（１００−２００ｍｅｓｈ）を用いて後記スケジュールＡに従って合成を開始し、工程５まで進んだ後、工程２へ戻ることでαアミノ基の脱保護、洗浄、カップリング、洗浄を繰り返し、Ｆｍｏｃ−Ｇｌｙ−ＯＨ、Ｆｍｏｃ−Ｐｒｏ−ＯＨ、Ｆｍｏｃ−Ｇｌｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ａｒｇ（Ｐｂｆ）−ＯＨ、Ｆｍｏｃ−Ｇｌｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨ、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨを順次カップリングさせた結果、ペプチド結合樹脂を得た。ペプチドは工程６に示す試薬との反応によって樹脂から切り離され、冷メチルタートブチルエーテル（ＭＴＢＥ）中にろ過され、沈殿させた。沈殿したペプチドは２回冷ＭＴＢＥで洗浄され、窒素下で凍結乾燥された。

得られた粗ペプチドはＢｉｏＣａｄ ６０（Ｐｅｒｋｉｎ−Ｅｌｍｅｒ，Ｆｏｓｔｅｒ Ｃｉｔｙ ＣＡ）により、粒子サイズ１０ミクロンのＣ１８カラム（Ｐｈｅｎｏｍｅｎｅｘ，Ｔｏｒｒａｎｃｅ，ＣＡ）を用いて逆相ＨＰＬＣ法によって精製された。流速２０ｍｌ／ｍｉｎ，４５分で１０％Ｂから８０％Ｂ（溶媒Ａ：０．０５％ＴＦＡ／Ｈ_２Ｏ，溶媒Ｂ：０．０５％ＴＦＡ／アセトニトリル）の直線濃度勾配で溶出し、溶出液をＡ２２０ｎｍでモニターした。面積割合で９０％以上を占める主ピークの質量分析をＬａｓｅｒｍａｔ ２０００（Ｆｉｎｎｉｇａｎ Ｍａｔ，Ｓａｎ Ｊｏｓｅ，ＣＡ）を用い、ＭＡＬＤＩ−ＴＯＦ法で行なった結果、理論値［ＭＨ＋］１１０９．３に対し、実測値１１０９．９を得た。
［参考例２］ Ｐｈｅ−Ｐｈｅ−Ｇｌｎ−Ａｒｇ−Ｌｅｕ−Ｇｌｎ−Ｐｒｏ−Ｇｌｙ−Ｌｅｕ（配列番号６）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｇｌｙ−ＯＨ、Ｆｍｏｃ−Ｐｒｏ−ＯＨ、Ｆｍｏｃ−Ｇｌｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ａｒｇ（Ｐｂｆ）−ＯＨ、Ｆｍｏｃ−Ｇｌｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ＋］１１３１．３に対し、実測値１１３０．４を得た。
［参考例３］ Ｍｅｔ−Ｐｈｅ−Ｌｙｓ−Ａｓｎ−Ａｓｎ−Ｔｙｒ−Ｐｒｏ−Ｓｅｒ−Ｌｅｕ（配列番号７）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｐｒｏ−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ａｓｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ａｓｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｌｙｓ（Ｂｏｃ）−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨ、Ｆｍｏｃ−Ｍｅｔ−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ＋］１０３１．２に対し、実測値１０３２．３を得た。
［参考例４］ Ｐｈｅ−Ｔｈｒ−Ａｓｐ−Ｖａｌ−Ｓｅｒ−Ｌｅｕ−Ｔｙｒ−Ｉｌｅ−Ｌｅｕ（配列番号８）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｉｌｅ−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｖａｌ−ＯＨ、Ｆｍｏｃ−Ａｓｐ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｔｈｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ−］１１２１．３に対し、実測値１１２２．１を得た。
［参考例５］Ｌｙｓ−Ｐｈｅ−Ｓｅｒ−Ｌｙｓ−Ａｓｐ−Ｃｙｓ−Ｇｌｙ−Ａｒｇ−Ｍｅｔ−Ｌｅｕ（配列番号９）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｍｅｔ−ＯＨ、Ｆｍｏｃ−Ａｒｇ（Ｐｂｆ）−ＯＨ、Ｆｍｏｃ−Ｇｌｙ−ＯＨ、Ｆｍｏｃ−Ｃｙｓ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ａｓｐ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｌｙｓ（Ｂｏｃ）−ＯＨ、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨ、Ｆｍｏｃ−Ｌｙｓ（Ｂｏｃ）−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ−］１１０８．３に対し、実測値１１１１．４を得た。
［参考例６］ Ｔｒｐ−Ｔｙｒ−Ｃｙｓ−Ｓｅｒ−Ｔｙｒ−Ｃｙｓ−Ｇｌｎ−Ｇｌｙ−Ｌｅｕ（配列番号１０）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｇｌｙ−ＯＨ、Ｆｍｏｃ−Ｇｌｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｃｙｓ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｃｙｓ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｔｒｐ（Ｂｏｃ）−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ＋］１１１４．３に対し、実測値１１１５．７を得た。
［参考例７］ Ｌｙｓ−Ｔｙｒ−Ｔｒｐ−Ａｒｇ−Ｇｌｕ−Ｔｙｒ−Ｉｌｅ−Ｌｅｕ−Ｓｅｒ−Ｌｅｕ（配列番号１１）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ｉｌｅ−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｇｌｕ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ａｒｇ（Ｐｂｆ）−ＯＨ、Ｆｍｏｃ−Ｔｒｐ（Ｂｏｃ）−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｌｙｓ（Ｂｏｃ）−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ−］１１０４．３に対し、実測値１１０５．３を得た。
［参考例８］ Ｇｌｕ−Ｔｙｒ−Ｉｌｅ−Ｌｅｕ−Ｓｅｒ−Ｌｅｕ−Ｇｌｕ−Ｇｌｕ−Ｌｅｕ（配列番号１２）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｇｌｕ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｇｌｕ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ｉｌｅ−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｇｌｕ（Ｏｔｂｕ）−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ＋］１３７１．６に対し、実測値１３７０．７を得た。
［参考例９］ Ｉｌｅ−Ｔｙｒ−Ａｓｐ−Ｍｅｔ−Ｇｌｕ−Ａｓｎ−Ｖａｌ−Ｌｅｕ−Ｌｅｕ（配列番号１３）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ｖａｌ−ＯＨ、Ｆｍｏｃ−Ａｓｎ（Ｔｒｔ）−ＯＨ、Ｆｍｏｃ−Ｇｌｕ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｍｅｔ−ＯＨ、Ｆｍｏｃ−Ａｓｐ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｉｌｅ−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ＋］１２１１．４に対し、実測値１２１３．４を得た。
［参考例１０］ Ａｌａ−Ｔｙｒ−Ｔｙｒ−Ｐｒｏ−Ｇｌｕ−Ａｓｐ−Ｌｅｕ−Ｐｈｅ−Ｉｌｅ（配列番号１４）の合成
Ｆｍｏｃ−Ｉｌｅ−Ｗａｎｇ ｒｅｓｉｎを開始レジンとして用い、Ｆｍｏｃ−Ｐｈｅ−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ａｓｐ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｇｌｕ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｐｒｏ−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ａｌａ−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ−］１２１６．４に対し、実測値１２１７．４を得た。
［参考例１１］ Ｐｈｅ−Ｔｙｒ−Ｓｅｒ−Ａｌａ−Ｌｅｕ−Ｐｒｏ−Ｇｌｙ−Ｔｙｒ−Ｉｌｅ（配列番号１５）の合成
［参考例１０］と同様にＦｍｏｃ−Ｉｌｅ−Ｗａｎｇ ｒｅｓｉｎ（１００−２００ｍｅｓｈ）を開始レジンとして用い、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｇｌｙ−ＯＨ、Ｆｍｏｃ−Ｐｒｏ−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ａｌａ−ＯＨ、Ｆｍｏｃ−Ｓｅｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ＋］１１９３．４に対し、実測値１１９６．８を得た。
［参考例１２］ Ａｒｇ−Ｐｈｅ−Ｌｅｕ−Ａｌａ−Ｇｌｕ−Ｌｅｕ−Ａｌａ−Ｔｙｒ−Ａｓｐ−Ｌｅｕ（配列番号１６）の合成
［参考例１］と同様にＦｍｏｃ−Ｌｅｕ Ｗａｎｇ ｒｅｓｉｎを用い、Ｆｍｏｃ−Ａｓｐ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ｔｙｒ（ｔＢｕ）−ＯＨ、Ｆｍｏｃ−Ａｌａ−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ｇｌｕ（Ｏｔｂｕ）−ＯＨ、Ｆｍｏｃ−Ａｌａ−ＯＨ、Ｆｍｏｃ−Ｌｅｕ−ＯＨ、Ｆｍｏｃ−Ｐｈｅ−ＯＨ、Ｆｍｏｃ−Ａｒｇ（Ｐｂｆ）−ＯＨを順次結合させた。
質量分析の結果、理論値［ＭＨ−］１１８３．５に対し、実測値１１８６．７を得た。  We have described in Okube, H. et al. (Cancer Res. 61, 2129-2137 (2001)), and as a novel carcinoembryonic protein specifically overexpressed in human hepatocellular carcinoma based on cDNA microarray, glypican 3 (GPC3 ) Was identified. As a result of detecting GPC3 in serum, GPC3 is negative in cancers other than hepatocellular carcinoma, such as cancers of stomach, esophagus, lung, breast, pancreas, bile duct, colon, etc., and benign such as cirrhosis and chronic hepatitis It was confirmed that the liver disease was negative. Furthermore, the present inventors have also confirmed that post-operative serum GPC3 becomes negative in patients after surgical treatment of hepatocellular carcinoma.
  The amino acid sequence of the human GPC3 protein is known, and for example, Accession No. It is registered as NP 004475 and can be easily obtained by those skilled in the art. The present inventors next considered that when various proteins are presented on antigen-presenting cells in vivo, they are presented after being decomposed into peptides consisting of 9 amino acids (nonapeptides). A partial peptide consisting of 9 amino acids or 10 amino acids derived from GPC3 having a binding motif for HLA-A24, which accounts for 60% of the whole human, was synthesized.
  Selection of a peptide having a binding motif for HLA-A24 can be performed, for example, based on the method described in (J. Immunol., 152, 3913, 1994; J. Immunol. 155: 4307, 1994). Peptides can be selected similarly for HLA types other than HLA-A24. Alternatively, software that has recently become available on the Internet, such as Parker K. et al. C. , J .; Immunol. The binding affinity between various peptides and HLA molecules (sometimes referred to as HLA antigens) can also be calculated in silico using those described in 152, 1994 and the like. The binding affinity with the HLA molecule can be determined by, for example, BIMAS: HLA Binding Prediction: http: // bimas. dcrt. nih. gov / molbio / hla_bind / (Parker, K.C., et al., J. Immunol., 152, 1994), or Nukaya, I .; , Int. J. et al. It can be estimated using the method described in Cancer, 80, 1999, etc.
  9-mer and 10-mer peptides can be obtained by synthesizing peptides from any position based on the entire amino acid sequence of the obtained GPC3 protein. Peptide synthesis can be performed according to methods used in normal peptide chemistry. Commonly used synthesis methods are described, for example, in Peptide Synthesis, Interscience, New York, 1966; The Proteins, Vol 2, Academic Press Inc. , New York, 1976; Peptide synthesis, Maruzen Co., Ltd., 1975; Fundamentals and experiments of peptide synthesis, Maruzen Co., Ltd., 1985; Development of pharmaceuticals continued Vol. 14, peptide synthesis, Hirokawa Shoten, 1991, It is described in publications such as International Publication WO99 / 67288. The actual binding between the HLA molecule and the peptide is carried out by incubating a transfectant expressing the HLA gene with the TAP-deficient T2 or RMA-S cell line and the peptide, and then transferring the HLA class I molecule expressed on the cell surface to the flow site. Can be measured quantitatively with a meter (see, eg, Immunol. Lett. 2002 Aug 1,83 (1): 21-30; Immunogenetics, 44: 233-241, 1996; Nature 346: 321-325, 1990). thing).
  In order to obtain an effective result, it is preferable to use the A24 type possessed by many Japanese (60%) as the HLA molecule, and more preferably A^*Subtype such as 2402. However, in clinical practice, by examining the type of HLA molecule of a patient in need of treatment in advance, a peptide having high affinity for binding to this or cytotoxic T cell (CTL) induction by antigen presentation is appropriately selected. can do. Furthermore, in order to obtain a peptide having high binding affinity and CTL inducing ability, substitution or addition of one or two amino acids can be performed based on the amino acid sequence of a naturally occurring GPC3 partial peptide. In addition to peptides presented in nature, the regularity of the sequence of peptides presented in association with HLA molecules is already known (J. Immunol., 152, 3913, 1994; Immunogenetics. 41: 178, 1995; J. Immunol. 155: 4307, 1994), the obtained peptide may be modified based on these regularities. For example, in the case of HLA-A24 having high binding affinity, the second amino acid from the N-terminus of the peptide is substituted with phenylalanine, tyrosine, methionine or tryptophan, or the C-terminal amino acid is substituted with phenylalanine, leucine, isoleucine, tryptophan or methionine. The peptides thus obtained can also be used preferably.
  However, if the peptide sequence is the same as part of the amino acid sequence of an endogenous or foreign protein having other functions, side effects such as autoimmune diseases may occur or allergic symptoms to a specific substance may occur. It is preferable to perform a homology search using an available database and avoid matching with the amino acid sequences of other proteins. Furthermore, if it is clear from the homology search that there is no peptide having one or two amino acids different from each other, the modification of the amino acid sequence to increase the binding affinity to the HLA molecule and / or the ability to induce CTL is also like this. There is no fear of causing a serious problem.
  Peptides with high binding affinity with HLA molecules as described above are expected to be highly likely to be effective as cancer vaccines, but for candidate peptides selected using as an indicator that they have high binding affinity, It is necessary to examine whether or not it actually has the ability to induce CTL. Confirmation of CTL inducing ability can be achieved by, for example, inducing antigen-presenting cells (eg, B-lymphocytes, macrophages, dendritic cells) having HLA molecules, specifically dendritic cells derived from human peripheral blood mononuclear cells, etc. And then mixed with CD8 positive cells, and the cytotoxic activity against the target cells is measured. Alternatively, Nakatsura, T .; (Eur, J. Immunol. 32, 826-836 (2002)) can be used to induce peptide-specific CTLs from PBMCs. Furthermore, as a reaction system, a transgenic animal prepared to express a human HLA molecule (for example, Hum. Immunol. 2000 Aug .; 61 (8): 764-79 Related Articles, Books, Linkout Induction of CTL response by a minimal epitopic vaccine in HLA A * 0201 / DR1 transgenic rice: dependency on HLA class II restricted T (H) response., BenMohamed L., Jr. , Diamond DJ.) Can also be used. . Cytotoxic activity, for example, target cells^{5 1}It can be calculated from the radioactivity released from the target cells by radiolabeling with Cr or the like. Alternatively, it can also be observed by measuring spots visualized on the medium by IFN-γ and anti-IFN-γ monoclonal antibodies produced and released by CTLs in the presence of antigen-presenting cells loaded with peptides.
  As a result of examining the CTL inducing ability of peptides as described above, it was revealed that nonapeptides or decapeptides selected from peptides consisting of the amino acid sequences shown in SEQ ID NOs: 5 to 16 below have particularly high CTL inducing ability. .

  The present invention further provides a peptide having one or two amino acids substituted or added in the amino acid sequence shown in any of SEQ ID NOs: 5 to 16 and having the ability to induce cytotoxic T cells. One or two amino acid substitutions or additions may have CTL inducibility as long as there is no match with the amino acid sequence of other proteins. In particular, as amino acid substitutions, substitution of the second amino acid from the N-terminus with phenylalanine, tyrosine, methionine or tryptophan, and substitution of the C-terminal amino acid with phenylalanine, leucine, isoleucine, tryptophan or methionine are preferred examples.
  The peptide of the present invention can be used as a cancer vaccine capable of inducing CTL in vivo as one or a combination of two or more. By administration of the peptide of the present invention, the peptide is presented at a high density on the HLA molecule of the antigen-presenting cell, and CTL that specifically reacts to the complex of the presented peptide and the HLA molecule is induced, and the target cell Attack power against hepatocellular carcinoma cells that should be increased. Alternatively, by taking out dendritic cells from a subject and stimulating with the peptide of the present invention, antigen-presenting cells loaded with the peptide of the present invention on the cell surface can be obtained, and by administering this to the subject again, CTL can be reduced in the subject. It can induce and increase the attack power against the target cell.
  That is, the present invention provides a medicament for treating tumors or preventing tumor growth / metastasis and the like, which comprises one or more peptides of the present invention. In vivo and in vitro, stimulation of antigen-presenting cells by the peptide of the present invention causes the presence of a high concentration of the peptide in the cell to cause exchange with the peptide preloaded on the cell, Easy to do. For this reason, the binding affinity with the HLA molecule is required to be higher than a certain level.
  The medicament of the present invention may be directly administered alone with the peptide of the present invention, but may be administered as a pharmaceutical composition formulated by a commonly used pharmaceutical method. In that case, in addition to the peptide of the present invention, carriers, excipients and the like that are usually used in medicine can be appropriately included, and there is no particular limitation.
  A medicament for treating and / or preventing hepatocellular carcinoma comprising the peptide of the present invention as an active ingredient is administered together with an adjuvant so that cellular immunity is effectively established, or administered together with other active ingredients such as other anticancer agents. Or can be administered in a particulate dosage form. As the adjuvant, those described in the literature (Clin. Microbiol. Rev., 7: 277-289, 1994) can be applied. In addition, a liposome preparation, a particulate preparation bound to beads having a diameter of several μm, a preparation bound to lipid, and the like are also conceivable. As the administration method, oral administration, intradermal administration, subcutaneous administration, intravenous injection, and the like can be used, and systemic administration or local administration in the vicinity of the target tumor may be used. The dose of the peptide of the present invention can be appropriately adjusted according to the disease to be treated, the age, weight, administration method, etc. of the patient, but is usually 0.001 mg to 1000 mg, preferably 0.001 mg to 1000 mg, more preferably. It is preferably 0.1 mg to 10 mg, and is preferably administered once every several days to several months. A person skilled in the art can appropriately select an appropriate dose.
  Alternatively, the present invention provides intracellular vesicles called exosomes, which present a complex of the peptide of the present invention and an HLA molecule on the surface. The preparation of exosomes can be carried out using the methods described in detail in, for example, JP-T-11-510507 and JP-T 2000-512161. Preferably, the subject is subject to treatment and / or prevention. And using antigen-presenting cells obtained from The exosome of the present invention can be inoculated as a cancer vaccine in the same manner as the peptide of the present invention.
  The HLA molecule needs to be of the same type as the HLA molecule of the subject in need of treatment and / or prevention. For example, in the case of Japanese, HLA-A24, especially HLA-A^*2402 is often preferable.
  The present invention also provides a method for inducing antigen-presenting cells using the peptide of the present invention. Dendritic cells can be induced from peripheral blood monocytes and then contacted (stimulated) with the peptide of the present invention in vitro or in vivo to induce antigen-presenting cells. When the peptide of the present invention is administered to a subject, antigen-presenting cells loaded with the peptide of the present invention are induced in the body of the subject. Alternatively, the antigen-presenting cells can be administered to the subject as a vaccine after being loaded with the peptide of the present invention in vitro.
  The present invention also provides an antigen-presenting cell having a high cytotoxic T cell-inducing ability, which comprises introducing a gene encoding a partial peptide containing the GPC3 protein or the peptide of the present invention into an antigen-presenting cell in vitro. Provide a way to guide. The gene to be introduced may be in the form of DNA or RNA. Various methods such as lipofection, electroporation, calcium phosphate method and the like commonly used in the art may be used for the introduction, and there is no particular limitation. Specifically, for example, Cancer Res. 56: 5672, 1996; Immunol. 161: 5607, 1998; Exp. Med. 184: 465, 1996; JP 2000-509281. By introducing a gene into an antigen-presenting cell, the gene is subjected to processing such as transcription and translation in the cell, and then the obtained protein is subjected to HLA class I or class II processing and presentation pathway to present a partial peptide. The
  The present invention further provides a method for inducing CTL using the above-mentioned peptide of the present invention. When the peptide of the present invention is administered to a subject, CTL is induced in the subject's body, and immunity targeting hepatocellular carcinoma cells is enhanced. Alternatively, an ex vivo treatment method in which antigen-presenting cells and CD8-positive cells derived from a subject or peripheral blood mononuclear cells are contacted (stimulated) with the peptide of the present invention in vitro to induce CTL and then returned to the subject. Can be used.
  The present invention further provides isolated cytotoxic T cells induced using the peptides of the present invention. The cytotoxic T cells induced on the basis of stimulation by the antigen-presenting cells presenting the peptide of the present invention are preferably derived from the subject to be treated and / or prevented, either alone or in the present invention. It can be administered for the purpose of antitumor effect together with other drugs including peptides, exosomes and the like.
  The present invention further provides an antigen-presenting cell that presents a complex of the HLA molecule and the peptide of the present invention. The antigen-presenting cell obtained by contact with the peptide of the present invention, or GPC3 protein containing the peptide of the present invention, or a gene encoding a partial peptide thereof, is preferably derived from a subject to be treated and / or prevented And can be administered as a vaccine alone or together with other medicaments including the peptides of the present invention, exosomes, cytotoxic T cells and the like.
  The present invention further provides a diagnostic agent for hepatocellular carcinoma comprising an antibody against GPC3. The antibody against GPC3 may be either a polyclonal or monoclonal antibody, and can be prepared by a method known to those skilled in the art (for example, refer to “Shinsei Kagaku Kogaku Kenkyu 1, Protein I, 389-406, Tokyo Kagaku Dojin”). is there. The GPC3 protein has a known amino acid sequence as described above, and can be produced using a normal protein expression technique based on the amino acid sequence, or a commercially available product (Santa Cruz, CA) can be used. When using commercially available GPC3, if necessary, SDS-out^TM(Sodium Dodecyl Sulfate Precipitation Reagent; purchased from PIERCE, Rockford, IL) is preferably used except for SDS. A partial peptide of GPC3 can be produced by selecting an appropriate partial sequence from the amino acid sequence of GPC3 and using a normal peptide synthesis technique.
  For the preparation of a polyclonal antibody, first, GPC3 protein or a partial peptide thereof is administered as a sensitizing antigen to animals such as rabbits, guinea pigs, mice, rats, hamsters, chickens, monkeys, and the like. Administration may be performed with an adjuvant (FIA or FCA) that promotes antibody production. Administration is usually every few weeks. The antibody titer can be increased by performing immunization multiple times. After the final immunization, antiserum is obtained by collecting blood from the immunized animal. Polyclonal antibodies can be prepared by subjecting this antiserum to, for example, ammonium sulfate precipitation, fractionation by anion chromatography, or affinity purification using protein A or immobilized antigen.
  On the other hand, for preparation of a monoclonal antibody, for example, GPC3 protein or a partial peptide thereof is immunized to an animal in the same manner as described above, and after the final immunization, the spleen or lymph node is collected from the immunized animal. The antibody-producing cells and myeloma cells contained in the spleen or lymph node are fused using polyethylene glycol or the like to prepare a hybridoma. Cell fusion is basically performed according to a known method, for example, the method of Kohler and Milstein et al. (Kohler. G. and Milstein, C., Methods Enzymol. (1981) 73, 3-46). Can do. The obtained hybridoma is selected by culturing in a normal selective culture solution, for example, a HAT culture solution (a culture solution containing hypoxanthine, aminopterin and thymidine). The culture in the HAT culture solution is continued for a time sufficient for cells other than the target hybridoma (non-fusion cells) to die. Subsequently, the target hybridoma is screened, cultured, and a monoclonal antibody can be prepared from the culture supernatant.
  The antibody of the present invention may be produced in a host transformed with an expression vector containing an antibody gene by genetic engineering techniques. For example, as a monoclonal antibody, an antibody gene is cloned from a hybridoma, incorporated into an appropriate vector, introduced into a host, and a recombinant type produced using gene recombination technology can be used (for example, Vandamme, AM et al., Eur. J. Biochem. (1990) 192, 767-775, 1990).
  Any expression system, such as a eukaryotic or prokaryotic cell system, can be used for the production of the antibodies used in the present invention. Examples of eukaryotic cells include established mammalian cell systems, insect cell systems, filamentous fungal cells, and animal cells such as yeast cells. Examples of prokaryotic cells include bacterial cells such as E. coli cells. Next, the transformed host cell is cultured in vitro or in vivo to produce the desired antibody. Host cells are cultured according to a known method.
  The monoclonal antibody can be purified by, for example, ammonium sulfate precipitation, fractionation by anion chromatography, or affinity chromatography using protein A or an immobilized antigen. In addition, separation and purification methods used for ordinary proteins may be used.For example, by appropriately selecting and combining chromatography columns other than the affinity column, filters, ultrafiltration, salting out, dialysis, etc. Antibodies can be separated and purified.
  The antibody used in the present invention is not limited to the whole antibody molecule, and may be a fragment of an antibody or a modified product thereof as long as it binds to GPC3, and includes both a bivalent antibody and a monovalent antibody. For example, antibody fragments include Fab, F (ab ′) 2, Fv, Fab / c having one Fab and a complete Fc, or a single chain in which Fv of H chain or L chain is linked with an appropriate linker. And chain Fv (scFv). For the purposes of the present invention, the antibody may recognize any epitope of GPC3.
  For accuracy as a diagnostic agent, the antibody is preferably a human antibody or a human antibody. If the human antibody is, for example, a mouse-human chimeric antibody, an antibody gene is isolated from a mouse cell that produces an antibody against the GPC3 protein, and its heavy chain constant region is recombined with a human IgE heavy chain constant region gene. It can be prepared by introduction into tumor cells. A human antibody can be prepared by immunizing a mouse in which an immunoglobulin gene is replaced with a human by GPC3 protein.
  In the diagnostic agent of the present invention, the antibody can be used at a concentration of, for example, 1 μg / ml, although not limited thereto. In addition to the antibody against GPC3, the diagnostic agent can appropriately contain a pharmaceutically acceptable carrier and the like as necessary.
  The present invention further provides a method for diagnosing hepatocellular carcinoma, which comprises contacting a sample with an antibody against GPC3. The diagnostic method may further comprise quantifying GPC3 in the sample. In the present invention, examples of the sample include serum, saliva, urine and the like obtained from a subject who may suffer from HCC, and particularly preferably serum. The contact between the sample and the antibody may be performed based on a method commonly used in the art, and is not particularly limited. In the diagnosis, for example, after the contact between the sample and the antibody, the specific binding between GPC3 and the antibody that may be present in the sample is quantified using a secondary antibody labeled with a fluorescent substance, a luminescent substance, an enzyme, or the like. This can be done by detecting automatically. Further, the reaction for diagnosis may be performed in a liquid phase such as a well, or may be performed on a solid support on which an antibody against GPC3 is immobilized. In this case, whether the measured value is HCC positive by comparing with a standard value prepared in advance using a normal sample not affected by HCC or a sample known to be HCC Can be determined. In diagnosis, it is preferable to set a cutoff value by measuring the amount of GPC3 in serum of a large number of HCC patients and healthy individuals.
  The diagnostic method of the present invention can be used for diagnosing whether or not the patient is afflicted with HCC, and can also be performed over time to confirm the effect of treatment on HCC.
  Furthermore, the present invention provides a kit for diagnosing HCC comprising an antibody against GPC3. In addition to the antibody against GPC3, the kit can contain a secondary antibody, a standard sample for quantification, a buffer, and the like.
  EXAMPLES Hereinafter, although an Example is given and this invention is further demonstrated, this invention is not limited to these Examples.
[Example 1] Identification of GPC3 gene specifically overexpressed in HCC
  Gene expression profiling with cDNA microarrays was performed as previously reported (Okabe, H. et al., Cancer Res. 61, 1129-2137 (2001)). Primary HCC and corresponding non-cancerous liver tissue were obtained from 20 patients who underwent hepatectomy. Of these, 10 were positive for hepatitis B surface antigen, 10 were positive for hepatitis C virus (HCV), and no cases were infected with both HBV and HCV. There were no significant differences in age, sex, degree of differentiation, vascular invasion, tumor stage between HBV positive and HCV positive. A “genome-wide” cDNA microarray containing 23,040 cDNAs selected from the UniGene database of the National Center for Biotechnology Information was generated. Comparing expression profiles between HCC and corresponding non-cancerous liver tissue to search for genes that are specifically overexpressed in HCC, and as a result, are candidates for immunotherapy for HCC patients and possibly ideal GPC3, which could be a target, was identified. In 16 of the 20 HCCs, GPC3 mRNA expression in cancer tissues was more than 5-fold higher than in non-cancerous tissues (FIG. 1). That is, GPC3 was overexpressed in most HCCs and was not associated with hepatitis B virus (HBV) or HCV infection. On the other hand, GPC3 mRNA was highly expressed in the placenta, fetal liver, fetal lung, and fetal kidney, and was low in most adult normal tissues (FIG. 1). These GPC3 data were consistent with those published based on Northern blotting studies (Zhu, ZW et al., Gut 48, 558-564 (2001); Hsu. HC et al., Cancer Res). 57, 5179-5184 (1997); Pellegrini, M. et al., Dev Dyn. 213, 431-439 (1998)). From this result, it became clear that GPC3 is a novel carcinoembryonic antigen in HCC, similar to α-fetoprotein (AFP).
[Example 2] Expression of GPC3 mRNA and HLA-A24 in human HCC cell line
  GPC3 mRNA expression using reverse transcription-PCR (RT-PCR), anti-HLA class I (w6 / 32, IgG2a) or anti-HLA-A24 (IgG2) to select target HCC cell lines for CTL assays The expression of HLA-class I and -A24 was examined by immunostaining using a monoclonal antibody (VERITAS, Tokyo) and FITC-conjugated goat anti-mouse IgG (ICN / CAPPEL, Aurora, OH) and flow cytometry. The HCC cell lines Hep G2, Hep 3B, PLC / PRF / 5, and HuH-7 were obtained from Tohoku University Institute of Aging Medicine, Medical Cell Resource Center. SK-Hep-1 is a K.I. Granted by Dr. Itoh.
  RT-PCR was performed according to a known method (for example, Nakatsura, T. et al., Biochem. Biophys. Res. Commun. 281, 936-944 (2001)). A GPC3 gene-specific PCR primer that amplifies a 939 bp fragment was designed and used to perform an RT-PCR reaction consisting of 30 cycles of initial denaturation at 94 ° C. for 5 minutes and an annealing temperature of 58 ° C. The GPC3PCR primer sequence used was

  After normalization with the control β-actin mRNA, the expression of GPC3 mRNA in HCC cell lines was compared.
  The results showed strong expression of GPC3 mRNA in HepG2, Hep3B, and HuH-7 HCC cell lines, and moderate expression in PLC / PRF / 5 cell lines, but in SK-Hep-1 No significant expression was observed (FIG. 2). In addition, HepG2 and SK-Hep-1 expressed HLA-A24, but Hep3B and HuH-7 were not expressed.
[Example 3] Induction of tumor-responsive CTL by stimulation of peripheral blood mononuclear cells (PBMC)
  Based on the prior art (Kubo, RT, et al., J. Immunol. 152, 3913-3924 (1994)), GPC3-derived peptides expected to bind to the HLA-A24 molecule were searched. Different peptides were synthesized and used (Table 1). These peptides were synthesized using the Fmoc / PyBOP method (see Reference Examples 1 to 12 below) and purchased from biologica (Tokyo). The purity of the peptides was confirmed to exceed 95% by HPLC.

  After obtaining informed consent, HLA-A24 being treated in Kumamoto University School of Medicine Second Department of Surgery⁺Obtain a 30 ml blood sample from an HCC patient and isolate PBMC by Ficoll-Conray density gradient centrifugation as previously reported (Nakatsura, T. et al., Eur. J. Immunol. 32, 826-836 (2002)). did. For 12 types of peptides derived from glypican-3 having an HLA-A24 binding motif (Table 1, Nos. 1-12: corresponding to SEQ ID NOs: 5-16), 8 HLA-A24s⁺The ability to induce HLA-A24-restricted and tumor-responsive CTLs from PBMCs obtained from HCC patients (Pt1-8) was examined (FIG. 3, Table 1). As a method for deriving peptide-specific CTL from PBMC, the previously reported method (Nakatsura, T. et al., Eur. J. Immunol. 32, 826-836 (2002)) was used. The surface phenotype of CTL was examined by direct immunofluorescence staining using FITC-conjugated anti-CD3, -CD4, or -CD8 monoclonal antibodies (Nichirei, Tokyo). To determine effector cells and HLA restriction, 20 μg / ml each of anti-HLA-class I (W6 / 32, IgG2a), anti-HLA-A24 (0041HA, IgG2a), anti-CD8 (Nu) at the start of culture. -Ts / c, IgG2a), anti-HLA-DR (H-DR-1, IgG2a), and anti-CD4 (Nu-Th / I, IgG1) monoclonal antibodies were added. Anti-CD13 (MCS-2, IgG2a) and anti-CD14 (JML-H14, IgG1) monoclonal antibodies were used as isotype matched controls. After 3-4 weeks, the number of these CTL lines increased approximately 10-fold compared to the pre-culture number of PBMC. Next, the cytotoxic activity of these CTL lines against the HCC cell line was measured for 6 hours.⁵¹Examined by Cr release assay. The results are shown in FIG. 33 out of 96 (34.4%) CTL lines were HLA-A24⁻GPC3⁺Hep3B and HuH-7, and HLA-A24⁺GPC3⁻HLA-A24 than to SK-Hep-1⁺GPC3⁺It showed strong cytotoxicity against HepG2. This cytotoxicity is peptide specific and is inhibited by anti-HLA-class I, anti-CD8 or anti-HLA-A24 monoclonal antibodies, so that these T cell responses are HLA-A24 restricted CD8.⁺It is shown that it is carried by the CTL. The induction rate of CTL in each peptide or each patient is shown in Table 1. From these results, all 12 types of peptides derived from GPC3 have the ability to induce CTL and are HLA-A24-restricted GPC3-derived peptide-specific CD8.⁺It is shown that the CTL line was induced in all 8 HCC patients.
[Example 4] Expression of GPC3 protein in HCC
  Western blotting analysis and immunohistochemical analysis of GPC3 in HCC and non-cancerous areas around liver tissue excised from 4 HCC patients were performed.
  Western blotting was performed as follows. Samples were dissolved in appropriate amounts of lysis buffer (150 mM NaCl, 50 mM Tris, pH 7.4, 1% Nonidet P-40, 1 mM sodium orthovanadate (Wako Pure Chemical Industries, Ltd.), 1 mM EDTA, and protease inhibitor tablet (Amersham). , Arlington Heights, IL)). Lysate supernatants were electrophoresed on SDS-PAGE gels and transferred to nitrocellulose membranes (Bio-Rad, Hercules, CA). After blocking in Tris-buffered saline containing 5% skim milk, 0.2% Tween 20, the membrane was anti-GPC3 rabbit polyclonal prepared against a recombinant protein corresponding to the amino acids of GPC3 303-464. Incubate with antibody (Santa Cruz, California), wash well with PBS, peroxidase conjugated anti-rabbit Ig, horseradish peroxidase conjugated F (ab ')₂Chemiluminescence detection was performed using an ECL kit (Amercham) using a fragment (derived from donkey) (Amersham).
  Immunohistochemical analysis was performed according to methods known in the art (Nakatsura, T. et al., Biochem. Biophys. Res. Commun. 281, 936-944 (2001)). A 4 μm thick tissue sample section embedded in an OCT embedding compound was stained with anti-GPC3 antibody diluted 1: 200. FluoReporter Mini-Biotin-XX Protein Labeling Kit for biotinylation of GPC3 303-464 (Santa Cruz, CA) and anti-glypican-3 rabbit polyclonal antibody produced from E. coli as a 45 kDa tagged fusion protein for positive control (F-6347) (Molecular Probes, Inc., Eugene) was used. A 96-well ELISA plate (Nunc, Denmark) was coated overnight at 4 ° C. with 0.1 μg / well anti-human GPC3 303-464 (Santa Cruz) in PBS, pH 7.4. The plate was then blocked with 4% bovine serum albumin / PBS for 1 hour at room temperature. Positive control standard samples and culture supernatants were added with biotinylated anti-GPC3 antibody and incubated for 2 hours at room temperature. After washing 3 times with PBS, HRP-conjugated streptavidin (ENDOGEN, Woburn) was added to each well. After 30 minutes incubation, the plates were washed 3 times with PBS and TMB substrate solution (ENDOGEN) was added. An ELISA reader (Model 550, Bio-Rad) was used at 405 nm for analysis.
  After obtaining informed consent, tissue samples were obtained from HCC patients being treated in Kumamoto University School of Medicine Second Department of Surgery. Similar results were obtained in all four tumors where GPC3 protein expression was as low in HCC cells as in non-cancerous hepatocytes. Thus, there is a discrepancy between GPC3 mRNA expression and GPC3 protein expression in HCC cells. GPC3 is a GPI-anchored membrane protein and has been reported to be a secreted protein (Filmus J., Glycobiology 11, 19R-23R (2001)). Then, the detection of secreted GPC3 protein was tried next.
[Example 5] Detection of soluble GPC3 protein in culture supernatant of HCC cell line and serum of HCC patient
  In order to examine whether soluble GPC3 protein is present in the HepG2 culture supernatant, Western blotting was performed on the HepG2 cell lysate and culture supernatant collected after a predetermined culture period. 1 × 10 after 6, 12, 24, and 48 hours of culture in serum-free medium⁵Cell lysates prepared from individual HepG2 cells showed the presence of a similar amount of 60 kDa GPC3 protein (lanes 1, 3, 5, and 7 in FIG. 4). On the other hand, in the HepG2 culture supernatant (20 μl of 1 ml / well) after 6, 12, 24, and 48 hours of culture, the 60 kDa GPC3 protein was gradually increased, and the GPC3 protein was secreted from HepG2 into the culture supernatant. Showed that.
  Subsequently, detection by enzyme-linked immunosorbent assay (ELISA) was performed using anti-GPC3 303-464 antibody and biotinylated anti-GPC3 antibody. Using a commercially available recombinant protein corresponding to GPC3 303-464, the accuracy of quantification of GPC3 in the ELISA system was confirmed. A standard curve for quantifying GPC3 protein was evaluated based on OD data using serial dilutions of HepG2 culture supernatant. 1 × 10⁵The concentration of GPC3 protein in 1 ml of culture supernatant after culturing individual HepG2 cells for 24 hours was defined as 1 U / ml. The amount of GPC3 protein in the HepG2 culture supernatant was much higher than Hep3B, whereas it was not detectable in SK-Hep-1 (FIG. 5).
  Next, soluble GPC3 protein in HCC patient serum was detected (FIG. 6). Blood samples were collected from 28 HCC patients, patient profiles were collected from medical records, and clinical stage was determined based on UICC TNM classification. A 60 kDa GPC3 protein band was detected in 20 μl of serum from patient 7 (Pt7, lane 3 in FIG. 6), but not from the serum of the other 2 HCC patients and 4 healthy donors. . The amount of GPC3 protein in the serum of 28 HCC patients and 54 healthy donors (HD) was then assessed by ELISA (FIG. 7). The average GPC3 protein in the 54 HD sera was 0.75 U / ml, and the standard deviation (SD) was 0.32. There was no difference in expression between males and females, so the weak expression of GPC3 in the ovary was considered negligible for this system. The average value of 28 HCC patients was 1.98 U / ml. In order to determine the normal upper limit of GPC3 protein in serum, 1.71 was defined as the mean + 3SD of GPC3 protein of 54 HD sera. 35.7% (10/28) of HCC patients and 0% (0/54) of HD were GPC3 protein positive (> 1.71). The concentration of GPC3 protein in HCC patient serum was significantly higher than that in HD (P <0.0001). The concentrations of GPC3 evaluated by ELISA for patients 4, 5 and 7 were 0.94, 1.73 and 69.4 U / ml, respectively, as shown in FIG. 6 (Table 2). That is, 69.4 U / ml GPC3 protein could be detected by Western blotting, but 1.73 U / ml GPC3 could not be detected.
  As is apparent from the results in Table 2, two of the 10 GPC3-positive patients (patients 6 and 25) were negative for both AFP and PIVKA-II, while one patient (patient 6) was compared. As early UICC stage II. That is, since GPC3 may be positive in a patient who is negative for both AFP and PIVKA-II, it was revealed that GPC3 is useful as a novel tumor marker for HCC.

Reference Example 1 Synthesis of Ser-Phe-Phe-Gln-Arg-Leu-Gln-Pro-Gly-Leu (SEQ ID NO: 5)
  Synthesis was started according to Schedule A below using Fmoc-Leu-Wang resin (100-200 mesh) as the starting resin, proceeded to step 5 and then returned to step 2 to deprotect, wash and couple the α-amino group , Repeated washing, Fmoc-Gly-OH, Fmoc-Pro-OH, Fmoc-Gln (Trt) -OH, Fmoc-Leu-OH, Fmoc-Arg (Pbf) -OH, Fmoc-Gln (Trt) -OH, As a result of sequentially coupling Fmoc-Phe-OH, Fmoc-Phe-OH, and Fmoc-Ser (tBu) -OH, a peptide-bonded resin was obtained. The peptide was cleaved from the resin by reaction with the reagents shown in Step 6, filtered and precipitated into cold methyl tertbutyl ether (MTBE). The precipitated peptide was washed twice with cold MTBE and lyophilized under nitrogen.

  The resulting crude peptide was purified by the reverse phase HPLC method with a BioCad 60 (Perkin-Elmer, Foster City CA) using a C18 column (Phenomenex, Torrance, CA) with a particle size of 10 microns. 10% B to 80% B in 45 minutes at a flow rate of 20 ml / min (solvent A: 0.05% TFA / H₂O, solvent B: 0.05% TFA / acetonitrile), and the eluate was monitored at A220 nm. Mass analysis of the main peak occupying 90% or more by area ratio was performed by LaserMat 2000 (Finigan Mat, San Jose, Calif.) Using the MALDI-TOF method. As a result, the measured value was an actual value [MH +] 1109.3. 1109.9 was obtained.
Reference Example 2 Synthesis of Phe-Phe-Gln-Arg-Leu-Gln-Pro-Gly-Leu (SEQ ID NO: 6)
  Similarly to [Reference Example 1], Fmoc-Leu-Wang resin was used as a starting resin, and Fmoc-Gly-OH, Fmoc-Pro-OH, Fmoc-Gln (Trt) -OH, Fmoc-Leu-OH, Fmoc-Arg (Pbf) -OH, Fmoc-Gln (Trt) -OH, Fmoc-Phe-OH, and Fmoc-Phe-OH were sequentially combined.
  As a result of mass spectrometry, an actual measurement value 1130.4 was obtained with respect to the theoretical value [MH +] 1131.3.
Reference Example 3 Synthesis of Met-Phe-Lys-Asn-Asn-Tyr-Pro-Ser-Leu (SEQ ID NO: 7)
  As in [Reference Example 1], using Fmoc-Leu-Wang resin as a starting resin, Fmoc-Ser (tBu) -OH, Fmoc-Pro-OH, Fmoc-Tyr (tBu) -OH, Fmoc-Asn (Trt) -OH, Fmoc-Asn (Trt) -OH, Fmoc-Lys (Boc) -OH, Fmoc-Phe-OH, and Fmoc-Met-OH were sequentially combined.
  As a result of mass spectrometry, an actual measurement value 1032.3 was obtained with respect to the theoretical value [MH +] 1031.2.
Reference Example 4 Synthesis of Phe-Thr-Asp-Val-Ser-Leu-Tyr-Ile-Leu (SEQ ID NO: 8)
  As in [Reference Example 1], using Fmoc-Leu-Wang resin as a starting resin, Fmoc-Ile-OH, Fmoc-Tyr (tBu) -OH, Fmoc-Leu-OH, Fmoc-Ser (tBu) -OH, Fmoc-Val-OH, Fmoc-Asp (Otbu) -OH, Fmoc-Thr (tBu) -OH, and Fmoc-Phe-OH were sequentially combined.
  As a result of mass spectrometry, an actually measured value 1122.1 was obtained with respect to the theoretical value [MH−] 1121.3.
Reference Example 5 Synthesis of Lys-Phe-Ser-Lys-Asp-Cys-Gly-Arg-Met-Leu (SEQ ID NO: 9)
  Similarly to [Reference Example 1], using Fmoc-Leu-Wang resin as a starting resin, Fmoc-Met-OH, Fmoc-Arg (Pbf) -OH, Fmoc-Gly-OH, Fmoc-Cys (Trt) -OH, Fmoc-Asp (Otbu) -OH, Fmoc-Lys (Boc) -OH, Fmoc-Ser (tBu) -OH, Fmoc-Phe-OH, and Fmoc-Lys (Boc) -OH were sequentially combined.
  As a result of mass spectrometry, a measured value 1111.4 was obtained with respect to the theoretical value [MH−] 1108.3.
Reference Example 6 Synthesis of Trp-Tyr-Cys-Ser-Tyr-Cys-Gln-Gly-Leu (SEQ ID NO: 10)
  As in [Reference Example 1], using Fmoc-Leu-Wang resin as a starting resin, Fmoc-Gly-OH, Fmoc-Gln (Trt) -OH, Fmoc-Cys (Trt) -OH, Fmoc-Tyr (tBu) -OH, Fmoc-Ser (tBu) -OH, Fmoc-Cys (Trt) -OH, Fmoc-Tyr (tBu) -OH, and Fmoc-Trp (Boc) -OH were sequentially combined.
  As a result of mass spectrometry, an actually measured value 1115.7 was obtained with respect to the theoretical value [MH +] 1114.3.
Reference Example 7 Synthesis of Lys-Tyr-Trp-Arg-Glu-Tyr-Ile-Leu-Ser-Leu (SEQ ID NO: 11)
  As in [Reference Example 1], using Fmoc-Leu-Wang resin as a starting resin, Fmoc-Ser (tBu) -OH, Fmoc-Leu-OH, Fmoc-Ile-OH, Fmoc-Tyr (tBu) -OH, Fmoc-Glu (Otbu) -OH, Fmoc-Arg (Pbf) -OH, Fmoc-Trp (Boc) -OH, Fmoc-Tyr (tBu) -OH, and Fmoc-Lys (Boc) -OH were sequentially combined.
  As a result of mass spectrometry, an actual measurement value 1105.3 was obtained with respect to the theoretical value [MH−] 1104.3.
Reference Example 8 Synthesis of Glu-Tyr-Ile-Leu-Ser-Leu-Glu-Glu-Leu (SEQ ID NO: 12)
  As in [Reference Example 1], using Fmoc-Leu-Wang resin as a starting resin, Fmoc-Glu (Otbu) -OH, Fmoc-Glu (Otbu) -OH, Fmoc-Leu-OH, Fmoc-Ser (tBu) -OH, Fmoc-Leu-OH, Fmoc-Ile-OH, Fmoc-Tyr (tBu) -OH, and Fmoc-Glu (Otbu) -OH were sequentially combined.
  As a result of mass spectrometry, an actual measurement value 1370.7 was obtained with respect to the theoretical value [MH +] 1371.6.
Reference Example 9 Synthesis of Ile-Tyr-Asp-Met-Glu-Asn-Val-Leu-Leu (SEQ ID NO: 13)
  Similarly to [Reference Example 1], using Fmoc-Leu-Wang resin as a starting resin, Fmoc-Leu-OH, Fmoc-Val-OH, Fmoc-Asn (Trt) -OH, Fmoc-Glu (Otbu) -OH, Fmoc-Met-OH, Fmoc-Asp (Otbu) -OH, Fmoc-Tyr (tBu) -OH, and Fmoc-Ile-OH were sequentially combined.
  As a result of mass spectrometry, an actually measured value 1213.4 was obtained with respect to the theoretical value [MH +] 1211.4.
[Reference Example 10] Synthesis of Ala-Tyr-Tyr-Pro-Glu-Asp-Leu-Phe-Ile (SEQ ID NO: 14)
  Using Fmoc-Ile-Wang resin as a starting resin, Fmoc-Phe-OH, Fmoc-Leu-OH, Fmoc-Asp (Otbu) -OH, Fmoc-Glu (Otbu) -OH, Fmoc-Pro-OH, Fmoc- Tyr (tBu) -OH, Fmoc-Tyr (tBu) -OH, and Fmoc-Ala-OH were sequentially combined.
  As a result of mass spectrometry, an actual measurement value 1217.4 was obtained with respect to the theoretical value [MH−] 1216.4.
Reference Example 11 Synthesis of Phe-Tyr-Ser-Ala-Leu-Pro-Gly-Tyr-Ile (SEQ ID NO: 15)
  As in [Reference Example 10], Fmoc-Ile-Wang resin (100-200 mesh) was used as the starting resin, and Fmoc-Tyr (tBu) -OH, Fmoc-Gly-OH, Fmoc-Pro-OH, Fmoc-Leu- OH, Fmoc-Ala-OH, Fmoc-Ser (tBu) -OH, Fmoc-Tyr (tBu) -OH, and Fmoc-Phe-OH were sequentially bonded.
  As a result of mass spectrometry, an actual measurement value 1196.8 was obtained with respect to the theoretical value [MH +] 1193.4.
Reference Example 12 Synthesis of Arg-Phe-Leu-Ala-Glu-Leu-Ala-Tyr-Asp-Leu (SEQ ID NO: 16)
  Fmoc-Leu Wang resin was used in the same manner as in [Reference Example 1], and Fmoc-Asp (Otbu) -OH, Fmoc-Tyr (tBu) -OH, Fmoc-Ala-OH, Fmoc-Leu-OH, Fmoc-Glu ( Otbu) -OH, Fmoc-Ala-OH, Fmoc-Leu-OH, Fmoc-Phe-OH, and Fmoc-Arg (Pbf) -OH were sequentially combined.
  As a result of mass spectrometry, an actual measurement value of 1186.7 was obtained with respect to the theoretical value of [MH−] 1183.5.

Industrial applicability

The present inventors have identified 12 peptides derived from GPC3, an oncofetal protein, as target immunotherapy targets for HLA-A24 ⁺ HCC patients. Regardless of overexpression of GPC3 in HCC patients, except for placenta, the expression of GPC3 is significantly lower in normal adult organs, indicating that GPC3 may be an ideal target for immunotherapy of HCC. Moreover, it was shown that the method of this invention is a very useful method for diagnosing whether it suffers from HCC. The inventors further identified a GPC3-derived peptide that is HLA-A24-restricted and capable of preparing HCC-reactive CTLs. The HLA-A24 allele is possessed by 60% of all Japanese people, and 95% of the genotype is A ^* 2402. 20% for Caucasians and 12% for Africans (Tokunaga, K. et al., Immunogenetics 46, 199-205 (1997); Imanishi, I. et al., Proceedings of the 11th International Histocompatibility. Et al.) 1065-1220 (Oxford University Press, Oxford, 1992)). These results revealed that GPC3 is very useful for specific immunotherapy or cancer diagnosis and prevention for many HCC patients worldwide.
All publications, patents and patent applications cited herein are incorporated herein by reference in their entirety.

Claims (12)

  A peptide comprising the amino acid sequence shown in any one of SEQ ID NOs: 5 to 16. SEQ ID NO: and one amino acid is substituted or added in the amino acid sequence shown in any of 5 to 16, and, a peptide having ability to induce cytotoxic T cells, the substitution wherein, the amino acid The peptide, wherein the second amino acid from the N-terminus of the sequence is substituted with phenylalanine, tyrosine, methionine or tryptophan, or the C-terminal amino acid of the amino acid sequence is substituted with phenylalanine, leucine, isoleucine, tryptophan or methionine . A medicament for treating and / or preventing a tumor, comprising one or more peptides according to claim 1 or 2 . An exosome presenting on its surface a complex comprising the peptide of claim 1 or 2 and an HLA molecule. The exosome according to claim 4 , wherein the HLA molecule is HLA-A24. The exosome of claim 5 , wherein the HLA molecule is HLA-A ^* 2402. A method for inducing antigen-presenting cells having high cytotoxic T cell-inducing ability in vitro using the peptide according to claim 1 or 2 . An antigen having a high cytotoxic T cell-inducing ability, which comprises introducing a gene encoding a glypican-3 (GPC3) protein or a partial peptide thereof including the peptide according to claim 1 or 2 into an antigen-presenting cell. A method of inducing presentation cells in vitro . A method for inducing cytotoxic T cells in vitro using the peptide according to claim 1 or 2 . An isolated cytotoxic T cell induced using the peptide according to claim 1 or 2 . An antigen-presenting cell presenting a complex of an HLA molecule and the peptide according to claim 1 or 2 . The antigen-presenting cell according to claim 11 , which is induced by the method according to claim 7 or 8 .

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