JPH07327686A - Variant type prex gene oligonucleotide of hepatitis b virus, polypeptide and method for detecting the same - Google Patents

Abstract

PURPOSE:To obtain the subject new oligonucleotide, having a specific base sequence, being a part of preX gene being a variant of hepatitis B virus and useful for examination, etc., for catching and estimating the change of morbid state of liver diseases due to hepatitis B virus. CONSTITUTION:This new HBV variant type preX gene oligonucleotide has a base sequence expressed by formula I to formula VI and is a part of preX gene which is a variant of hepatitis B virus and used for examination, etc., for catching and estimating the change of morbid state of liver diseases due to HBV as a primer for amplifying preX gene. The oligonucleotide can be obtained by a chemical synthesis according to the conventional method. The HBV variant type preX gene is detected by carrying out the first stage amplification using the oligonucleotide of formula I or II and/or the oligonucleotide of formula V or VI as a primer pair and then carrying out the second stage amplification using the oligonucleotide of formula III or IV.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the invention of preX gene and preX gene product which are mutants of hepatitis B virus, invention of a method for detecting anti-preX gene product antibody, and use for detection thereof. The present invention relates to an oligonucleotide, an antigenic polypeptide and an anti-preX gene product antibody.

[0002]

2. Description of the Related Art Hepatitis B virus (HBV) not only causes acute hepatitis due to transient infection but sometimes causes death as fulminant hepatitis, and persistent infection causes chronic hepatitis, cirrhosis, and liver cancer. It is known to be a virus that causes various pathological conditions such as. It is said that there are 200 million people in the world who are infected with HBV.
The social damage is enormous.

In order to eradicate HBV infection, HBV
Administration of vaccination using the coat protein of the above, or HBs antigen test of donated blood for the purpose of preventing transfusion of contaminated blood,
The anti-HBs antibody test and also the anti-HBc antibody test are effective. In Japan, the blood donation test system was introduced and developed by the Japanese Red Cross Society, and the results were remarkable.

[0004] On the other hand, on the other hand, although various studies have been conducted on treatment methods for HBV-infected persons, the cause and the treatment method at each stage, especially regarding the seriousness of the pathological condition from chronic hepatitis to cirrhosis to liver cancer. Has not yet been established, and the development of a test method that appropriately grasps and predicts the mutation of the pathological condition has been awaited.

The HBV gene was cloned in 1979 and the entire nucleotide sequence has been determined. According to this, a circular incomplete double-stranded DNA of about 3200 bases
It has been reported that there is an open reading frame that defines the type of protein. Of these, the X gene is known to activate the transcriptional activity of viral genes, and also to activate the cancer-related genes possessed by host cells in trans. Therefore, the relationship with pathological conditions including carcinogenesis has been particularly noted. There is.

[0006] Furthermore, recently, the X gene upstream 16
HB with a new read start codon at 8 bases
It was reported that the V strain existed, and the gene started to read from this start codon was named preX gene. However, it was unclear whether the preX gene actually functions.

[0007] As a result of engaging in research on the X gene product in the serum of HBV-infected patients, the present inventor has found that the X gene product, which is molecularly larger than the X gene product estimated from the conventionally known length of the X gene. It was found that the preX gene was actually expressed, and that the actual state of the expression was different from that previously estimated.

That is, some HBVs have a mutant preX gene, and in this mutant strain, preX
It was found that the stop codon at the 43rd position from the gene start codon was mutated and changed to another sense codon, resulting in the formation of a continuous long open reading frame. It was confirmed that this mutant preX gene produces the large gene product described above.

The present inventors have studied HBV-asymptomatic carriers and HBV-DNA isolated from patients with chronic liver disease, respectively, and as a result, the positive strain level of the mutant strain was higher than that of asymptomatic carriers. It was confirmed to be significantly higher in patients with liver disease.

Further, as a result of the research conducted by the present inventors,
A mutant strain of the preX gene (hereinafter referred to as "mutant preX gene strain", and this type-specific preX gene is referred to as "mutant pX gene strain".
It was also confirmed that the degree of detection of "reX gene") increases in response to the seriousness of the disease state from chronic hepatitis to cirrhosis and liver cancer.

From the above facts, the present inventor has found that the mutant pr
It was confirmed that examining the presence of the eX gene and the presence or absence of the expression product thereof can make a great contribution to grasping the pathological condition of a disease caused by HBV and predicting its transition, and the present invention Was completed.

[0012]

As mentioned above, the HB
Regarding the prevention of V infection, although a test system has been established, the establishment of a method for confirming the pathological condition caused by HBV infection and predicting its transition has been awaited. The present invention identifies a mutant preX gene and its gene product at the molecular level, and uses these to identify mutant HBV
The purpose of the present invention is to detect the presence or absence of the preX gene and its gene product, and thereby solve the above problems.

[0013]

The present inventors have isolated HBV-DNA from the sera of asymptomatic HBV carriers, patients with chronic hepatitis, patients with cirrhosis, and patients with liver cancer, and have isolated the bases of the viral gene region including the preX region. The sequence was determined. As a result, the present inventors confirmed that, on the one hand, there is a highly conserved preX gene sequence common to each virus strain, and on the other hand, there is a mutant strain in which the degree of detection increases with the transition of pathological conditions. The present invention has been completed by elucidating and identifying the gene sequence.

The gist of the present invention is as follows. That is, the present invention is the invention of the oligonucleotides shown in SEQ ID NOS: 1 to 6 or the polypeptide shown in SEQ ID NOS: 7 or 8, and an anti-preX antibody that binds to the antigenic peptide shown in SEQ ID NOS: 7 or A method for detecting a hepatitis B mutant preX gene, which comprises gene amplification using an oligonucleotide having the nucleotide sequence of SEQ ID NO: 3 or SEQ ID NO: 4 as a primer pair, an oligonucleotide of SEQ ID NO: 1 or SEQ ID NO: 2, and / or Alternatively, the oligonucleotides of SEQ ID NO: 5 and SEQ ID NO: 6 are used as a primer pair to perform the first-stage preX gene amplification, and then the oligonucleotides of SEQ ID NO: 3 and SEQ ID NO: 4 are used to perform the second-stage gene amplification. Method for detecting hepatitis B mutant preX gene to be carried out, oligonue according to SEQ ID NO: 1 or SEQ ID NO: 2 Reochido, and / or SEQ ID NO: 5,
A method for detecting a hepatitis B mutant preX gene, which is treated with a restriction enzyme BalI or Sau3AI after gene amplification using the oligonucleotide of SEQ ID NO: 6 as a primer pair, SEQ ID NO: 3 and / or SEQ ID NO: 4
Method for detecting hepatitis B mutant preX gene using the described oligonucleotide as a labeling probe, and B capturing a mutant preX gene using any of the oligonucleotides of SEQ ID NOs: 1 to 6 as a capture probe A method for detecting hepatitis B mutant preX gene,
A method for detecting a hepatitis B mutant preX gene, which comprises capturing an anti-preX antibody using the polypeptide of SEQ ID NO: 7 as an antigen and binding the labeled anti-human immunoglobulin antibody to the polypeptide of SEQ ID NO: 7 or 8. Method for detecting anti-preX antibody used as antigen, method for detecting hepatitis B mutant preX gene for capturing preX gene product using anti-preX antibody, and binding capture product with labeled anti-preX gene product antibody, sequence A hepatitis B virus preX gene product polyclonal antibody or monoclonal antibody obtained by immunizing an animal with the polypeptide of No. 7 or 8, and the detection of hepatitis B preX gene product using the polyclonal antibody or monoclonal antibody of claim 20. The invention of the method.

The oligonucleotides shown in SEQ ID NOS: 1 to 6 can be obtained by chemical synthesis according to a conventional method,
Polymerase chain reaction method (hereinafter referred to as "PCR
Method)), etc., or as a probe for capture. Further, it can be used as a labeled probe after being labeled with an enzyme or a radioisotope. Oligonucleotide # HX-1 described in SEQ ID NO: 1, SEQ ID NO: 2
The described oligonucleotide # HX-2 can be used for both wild type and mutant type. In particular, in the gene amplification method, the former can be used as a sense primer and the latter can be used as an antisense primer.

Oligonucleotide #H shown in SEQ ID NO: 3
X-4, oligonucleotide # HX- described in SEQ ID NO: 4
5 can be used specifically for the mutant type, and particularly in the gene amplification method, the former can be used as a sense primer and the latter as an antisense primer. # HX-1 / # HX-2 when using the PCR method
It is effective to use the amplification product obtained by using the primer pair of 2) as the primer pair of the second step PCR. The amplification product obtained by the primer pair has a length of 120 bp.

Oligonucleotide $ 0 described in SEQ ID NO: 5
44, the oligonucleotide $ 045 described in SEQ ID NO: 6 can be used commonly for wild type and mutant type, and particularly in the gene amplification method, the former can be used as a sense primer and the latter as an antisense primer. # HX-1 / # HX-2 when using the PCR method
It is effective to use the amplification product obtained by using the primer pair of 2) as the primer pair of the second step PCR. The amplification product obtained by the primer pair has a length of 233 bp.

The present inventors obtained serum from blood donors and patients with chronic liver disease (chronic hepatitis, liver cirrhosis, hepatocellular carcinoma disease patients), extracted DNA according to a conventional method, and, as shown in Examples, preX gene. The base sequence containing the region was determined. By comparing the nucleotide sequences of these HBV-DNAs, oligonucleotides conserved in all types of preX genes and having properties suitable for gene detection methods involving gene amplification were identified, and SEQ ID NOS: 1, 2 and 5 were identified. , 6 were obtained. Furthermore, by comparing the HBV-DNA nucleotide sequences for each disease state of liver disease with each other,
The nucleotide sequence of the preX gene of the mutant strain was identified. Oligonucleotides unique to the mutants, SEQ ID NOS: 3 and 4
Was identified, and it was possible to obtain it. As a result, the present invention can provide oligonucleotides 3 and 4 that can be suitably used for detecting mutant strains.

Therefore, if the oligonucleotides of SEQ ID NOs: 3 and 4 are used as a primer pair and the polymerase chain reaction is carried out, the target gene can be detected by amplifying the gene. Furthermore, the target gene can also be detected by utilizing the high specificity of the above-mentioned oligonucleotide for the target gene and using the oligonucleotide as a capture probe and / or a labeled probe.

When the amount of HBV-DNA is small, pr
It is preferable to search a wide range of gene sequences, including the eX region. From this, the present inventors have found that the oligonucleotides of SEQ ID NOs: 5 and 6 having high conservation in the region flanking the preX region are used as primers, and by combining with the gene amplification method described above, D
The inventors have invented a method capable of detecting the preX gene with high sensitivity even when the NA amount is low. We have
A two-step gene amplification method was invented, in which the oligonucleotides of SEQ ID NOs: 5 and 6 were used as a primer pair to perform the first-step amplification, and then the above-described preX gene-specific amplification was performed.

As a method for detecting a gene, there is a method in which the amplified gene is electrophoresed after gene amplification and DNA is confirmed as a band. In addition to this, specific oligonucleotide 3
Or using any of 4 as a capture probe and an oligonucleotide having complementarity to the other specific oligonucleotide as a labeled probe,
A method for detecting the preX gene by capturing the preX gene in the sample and then binding it to a labeled probe, or physically or chemically binding the amplified gene to an appropriate membrane and then reacting and binding with the labeled probe There are detection methods and the like.

Further, the present inventors have invented a detection method using a restriction enzyme. That is, in the preX gene amplified using the oligonucleotides of SEQ ID NOs: 1 and 2 and / or SEQ ID NOs: 5 and 6 as primers, the wild type has a cleavage site for the restriction enzyme BalI, but the mutant p
The cleavage site does not exist in the reX gene. As a result, the mutant preX gene can be detected, and the ratio of both types of virus can be detected in the mixed infection (FIG. 3).

Similarly, since it has a restriction enzyme Sau3AI recognition site, it is possible to detect mutant genes by Sau3AI treatment and to detect the ratio of both types of viruses in mixed infection (FIG. 3).

Furthermore, the inventors obtained the antigenic peptides of SEQ ID NOS: 7 and 8 based on the gene sequences of the mutant strain and the wild strain. The polypeptide can be obtained by chemical synthesis by a conventional method, or can be obtained by incorporating it into Escherichia coli, yeast or the like using a suitable vector and expressing it.

The polypeptide shown in SEQ ID NO: 7 is a mutant p
It has an amino acid sequence translated from the reX gene and can be used for diagnosing liver disease by measuring a specific antibody in a sample by an immunological assay using this as an antigen. The polypeptide of SEQ ID NO: 8 has an amino acid sequence that is translated when the stop codon at the 43rd position from the start codon in the wild-type preX gene is mutated and the reading is continuously performed. The specific antibody in a sample can be measured by an immunoassay using this as an antigen and used for diagnosis of liver disease. It is also useful to compare the reactivity of specific antibodies that react with the above two peptides.

Further, animals are immunized with the polypeptide shown in SEQ ID NO: 7 and the polypeptide shown in SEQ ID NO: 8, respectively,
A polyclonal antibody or a monoclonal antibody can be obtained according to a conventional method. The obtained anti-mutant preX-specific antibody or anti-wild-type preX-specific antibody is subjected to immunoassay such as sandwich EIA method or Western blotting method by combination of specific antibodies or combination with anti-human immunoglobulin antibody. It can be used to measure the antigen in a sample.

[0027]

According to the method of the present invention, the mutant preX gene can be specifically detected, and the pathological change of liver disease due to HBV can be appropriately grasped. The oligonucleotide or polypeptide of the present invention can be used in the above detection method.

[0028]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0029]

Example 1 The nucleotide sequence and amino acid sequence of HBVpreX gene in HBV asymptomatic carriers and various cases of type B liver disease were determined as follows. (1) DNA extraction From the serum of asymptomatic carriers of HBV, patients with chronic hepatitis, patients with liver cirrhosis, and patients with hepatocellular carcinoma, the method previously published by the present inventors (Okamoto et al., J. Virol. 1).
DNA was extracted according to (990: 64: 1298-1303). (2) Determination of nucleotide sequence DNA was extracted from 50 μl of serum according to the method of (1) and then dissolved in 50 μl of distilled water. This DN
45 nl of 400 nM of the oligonucleotides shown in Sequence Listing 1 and 2 for 5 μl of solution A is contained as a primer pair 45
μl Polymerase chain reaction solution (D
NA amplification reagent
Kit: Perkin-Elmer Cetus) DN
A thermal cycler (Perkin-E
gene amplification was carried out according to the usual method using Lmer Cetus (Saiki et al., Sci).
ence 239: 487-491, 1988). The reaction cycle consisted of denaturation (94 ° C., 1 minute), primer annealing (55 ° C., 1 minute 30 seconds), extension (72 ° C., 2 minutes), and this cycle was repeated 35 times for amplification. The amplified gene is Microcon 100 (Amic
on. Inc.), and a commercially available kit (PRI
SM Ready Reaction Dye Ter
minator Cycle sequencing
Kit: Applied Biosystems, In
c) and react with 373 DNA Sequence.
cer (Applied Biosystems, In
Sequenced using c). Furthermore, when a sample obtained from an HBe antibody-positive person who is expected to have a low viral load is used, the oligonucleotide of SEQ ID NO: 5 or 6 is used as a primer, and the above method is followed by a primer annealing step. ℃ 1 minute, extension step 72 ℃
The gene amplification work carried out after changing to 1 minute and 30 seconds was carried out subsequently. In this case, upon sequencing, the oligonucleotides shown in Sequence Listing 5 were used as primers instead of the oligonucleotides shown in Sequence Listing 1 to determine the sequence. Thereby, the nucleotide sequence containing the preX-X region was determined. (3) Determination of preX gene and mutant preX gene-specific sequence The sequence of the preX-X gene region of 57 clones was determined by the above work, and the obtained sequences were compared to determine pr
A sequence specific to the mutant preX gene sequence, which is conserved in eX and specific to fools, was searched. As a result, pre
As the X gene conservative oligonucleotide, the oligonucleotides having the sequences of SEQ ID NOs: 1 and 2 were used as mutant p
SEQ ID NO: 3 as an oligonucleotide specific to reX
And the oligonucleotides described in 4 were found.

[0030]

Example 2 (1) Establishment of Mutant preX Gene Sequence Detection System Using the mutant preX gene-specific oligonucleotide determined as described above as a primer pair, a mutant preX gene detection method by gene amplification method was established. .

(1) DNA extraction DNA was performed according to the method described above. (2) Gene amplification For gene amplification, the oligonucleotides shown in SEQ ID NOS: 1 and 2 are used as a primer set, or the oligonucleotides shown in 3 and 4 are used as a primer set, and the reaction conditions, equipment, and reagents described above are used. Amplified. (3) Sequencing of amplified gene The amplified gene was purified by the method described above, and the sequence was determined according to the method described previously. As a result, SEQ ID NO: 3,
It was found that by using the oligonucleotide of 4 as a primer pair, only the sequence specific to the mutant preX gene was amplified. Therefore, the above-mentioned oligonucleotide is useful for detecting a mutant preX gene,
It was confirmed that it could be specifically detected by the method described.

[0032]

Example 3 Detection of preX Gene and Mutant preX Gene Using Selected Oligonucleotides as Primers 143 HBsAg Positives (44 Donors, 54 Patients with Chronic Hepatitis, 24 Patients with Cirrhosis, Hepatocellular Carcinoma) 21 patients)
The DNA was extracted, and the preX gene (233 bp) was detected using SEQ ID NOs: 1 and 2 as a primer pair, and the mutant preX gene (120 bp) was detected using the oligonucleotides of SEQ ID NOs: 3 and 4 as a primer pair. The amount of sample used, the reaction conditions, and the reagents and equipment used are as described above. The results are shown in Table 1.

[0033]

[Table 1]

Mutant pre in HBs antigen-positive individuals
It was found that X gene positive persons were extremely low in asymptomatic HBV carriers (2.3%), but significantly higher in type B chronic liver disease patients (57.4-81%). In the group of chronic liver diseases, the positive rate was shown to increase with progression from chronic hepatitis to cirrhosis and liver cancer (57.4%,
75%, 81%), it was shown that this detection method is useful for distinguishing HBV asymptomatic HBV carriers from liver disease cases and predicting the pathological transition of type B chronic liver disease.

[0035]

Example 4 Detection of mutant preX gene in HBe anti-positive HBV disease patients and HBe antibody-positive HBV disease patients. About HBe antigen positive or HBe antibody positive asymptomatic carriers and liver disease patients Total HBV DNA
Among them, the mutant preX gene was examined.

DNA is extracted from the above HBV-DNA positive individuals according to the above-mentioned method, and this is diluted 10-fold with an appropriate diluent to prepare a diluted DNA series, which can be amplified and detected. The titer of the sample before dilution was calculated from the lowest concentration. Specifically, in 1 μl of the sample DNA solution,
The above-mentioned polymerase chain reaction reaction solution containing 40 nM of the oligonucleotides of SEQ ID NOs: 1 and 2 as a primer (DNA amplification
n reagent kit: Perkin-Elme
r Cetus) and denatured (9
A reaction cycle consisting of 4 ° C., 1 minute), primer annealing (60 ° C., 1 minute 30 seconds), and extension (72 ° C., 2 minutes) was repeated 30 times to perform the first stage amplification. A polymerase chain containing 400 nM of the oligonucleotides of SEQ ID NOS: 5 and 6 as a primer in the case of detecting the amplified product Total HBV DNA, and the oligonucleotides of SEQ ID NOS: 3 and 4 as a primer in the case of detecting the mutant preX gene. Reaction reaction solution (DNA amplification
eagent kit Perkin-Elmer Ce
tus) and denaturing (94 ° C, 1
Min), primer annealing (60 ° C, 1 min 30 min)
Second) and extension (72 ° C., 2 minutes), the reaction cycle was repeated 30 times to perform the second stage amplification. After amplification, electrophoresis was performed according to the method described above. The non-mutated preX gene was confirmed as a 233 bp (base length) band, and the mutant preX gene was confirmed as a 120 bp band.

As a result of the above work, in the case of liver disease, mutant p
It was found that the reX gene was detected in parallel with the total HBV DNA regardless of whether the HBe antigen was positive or the antibody was positive. It was shown that the presence or absence of the mutant preX gene is significantly related to the onset of pathological conditions.
It was confirmed that the eX gene is useful as a marker for pathological conditions. (Fig. 2)

[0038]

INDUSTRIAL APPLICABILITY The present invention can provide a method for detecting a mutant preX gene in the HBV gene and its gene product and anti-gene product antibody with high sensitivity, and an oligonucleotide, an antigenic peptide and an antibody which can be used for the method. Therefore, it is possible to accurately diagnose a hepatitis B patient, especially to grasp the pathological condition, and to provide useful information for treatment of viral hepatitis.

[0039]

[Sequence list]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[Brief description of drawings]

FIG. 1 shows the nucleotide sequences of the preX region of HBV-DNA obtained from asymptomatic carriers and patients with various liver diseases. In the numbers shown on the left side of the figure, (01) to (24) show asymptomatic carriers, and (25) to (57) show clones obtained from sera of patients with chronic liver disease, patients with liver cirrhosis, and patients with hepatocellular carcinoma.

[FIG. 2] Mutant preX gene titers (vertical axis) and to of asymptomatic carriers (○) and patients with various diseases (●) in the HBe antigen-positive group and the anti-HBe antibody-positive group.
Tal HBV DNA titer (horizontal axis) is shown.

FIG. 3 Restriction enzymes BalI and S in the regions corresponding to primers # HX-4 (SEQ ID NO: 1) and # HX-5 (SEQ ID NO: 2) in the wild-type and mutant-type DNA sequences, respectively.
The sequence part recognized by au3AI is shown. Bal
I acts only in the wild type and Sau3AI only in the mutant form.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G01N 33/566 33/576 B 33/577 B // A61K 39/395 S

Claims (20)

[Claims] 1. An oligonucleotide having the nucleotide sequence of SEQ ID NO: 1. 2. An oligonucleotide having the nucleotide sequence of SEQ ID NO: 2. 3. An oligonucleotide having the nucleotide sequence of SEQ ID NO: 3. 4. An oligonucleotide having the nucleotide sequence of SEQ ID NO: 4. 5. An oligonucleotide having the base sequence of SEQ ID NO: 5. 6. An oligonucleotide having the base sequence of SEQ ID NO: 6. 7. A polypeptide having the amino acid sequence of SEQ ID NO: 7. 8. A polypeptide having the amino acid sequence of SEQ ID NO: 8. 9. An anti-preX antibody which binds to the antigenic peptide of SEQ ID NO: 7. 10. A method for detecting a hepatitis B mutant preX gene, which comprises gene amplification using an oligonucleotide having the nucleotide sequence of SEQ ID NO: 3 or SEQ ID NO: 4 as a primer pair. 11. A first-step preX gene amplification using the oligonucleotides of SEQ ID NO: 1 and SEQ ID NO: 2 and / or the oligonucleotides of SEQ ID NO: 5 and SEQ ID NO: 6 as a primer pair, and then SEQ ID NO: 3 A method for detecting a hepatitis B mutant preX gene, which comprises performing a second-stage gene amplification using the oligonucleotide of SEQ ID NO: 4. (12) A gene which is amplified with the oligonucleotides of SEQ ID NO: 1 and SEQ ID NO: 2 and / or the oligonucleotides of SEQ ID NO: 5 and SEQ ID NO: 6 as a primer pair and then treated with a restriction enzyme BalI. A method for detecting a hepatitis B mutant preX gene. 13. A gene amplification using the oligonucleotides of SEQ ID NO: 1 and SEQ ID NO: 2 and / or the oligonucleotides of SEQ ID NO: 5 and SEQ ID NO: 6 as a primer pair, followed by treatment with a restriction enzyme Sau3AI B A method for detecting a hepatitis B mutant preX gene. 14. A method for detecting a hepatitis B mutant preX gene, which comprises using the oligonucleotide of SEQ ID NO: 3 and / or SEQ ID NO: 4 as a labeled probe. 15. A hepatitis B mutant pr which captures a mutant preX gene by using any of the oligonucleotides of SEQ ID NOs: 1 to 6 as a capture probe.
How to detect eX message. 16. A method for detecting an anti-preX antibody, which comprises using the polypeptide of SEQ ID NO: 7 or 8 as an antigen. 17. A method for detecting a hepatitis B mutant preX gene, which comprises capturing an anti-preX antibody using the polypeptide of SEQ ID NO: 7 as an antigen and binding it with a labeled anti-human immunoglobulin antibody. 18. A method for detecting a hepatitis B mutant preX gene, which comprises capturing a preX gene product using an anti-preX antibody and binding the captured product to a labeled anti-preX gene product antibody. 19. A hepatitis B virus preX gene product polyclonal antibody or monoclonal antibody obtained by immunizing an animal with the polypeptide of SEQ ID NO: 7 or 8. 20. A method for detecting a hepatitis B preX gene product, which uses the polyclonal antibody or the monoclonal antibody according to claim 19.