CN111378015A

CN111378015A - Synthetic peptide for detecting S.suis2 infection and application thereof

Info

Publication number: CN111378015A
Application number: CN201911370901.9A
Authority: CN
Inventors: 王晶; 潘秀珍; 高基民; 张会芳; 邹萍; 李娜
Original assignee: Wuxi Maternal and Child Health Hospital
Current assignee: Wuxi Maternal and Child Health Hospital
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2020-07-07
Anticipated expiration: 2039-12-27
Also published as: CN111378015B; CN112521458A; CN112521458B

Abstract

The invention discloses a synthetic peptide for detecting S.suis2 infection and application thereof. A synthetic peptide for detecting S.suis2 infection has an amino acid sequence shown in SEQ ID NO. 1. The synthetic peptide is used as a coating antigen and applied to preparation of a S.suis2 infection rapid auxiliary diagnosis kit. Experiments prove that the synthetic peptide can capture specific antibodies in human peripheral blood after S.suis2 infection, and can be used as a coating antigen to be applied to a rapid auxiliary diagnosis kit for S.suis2 infection. The invention provides a new idea for rapid auxiliary diagnosis of S.suis2, can reduce death caused by untimely diagnosis of S.suis2 infection, and has potential good clinical application value.

Description

Synthetic peptide for detecting S.suis2 infection and application thereof

Technical Field

The invention belongs to the field of medical detection, and relates to synthetic peptide for detecting S.suis2 infection and application thereof.

Background

Streptococcus suis type 2 (S.suis 2) belongs to the family of coccaceae, Streptococcus (Streptococcus), gram-positive facultative anaerobes, and is an important pathogenic bacterium of zoonotic infectious diseases. Suis2 can not only infect pigs to cause acute septicemia, meningitis, endocarditis and acute death, but also can cause infectious morbidity and death of people through transmission routes such as respiratory tract and wound. The disease is distributed globally, poses serious threat to the health of relevant practitioners and is determined to be an important new infectious disease pathogen. Suis2 infection epidemic is outbreak in large scale in the Jiangsu province and the Sichuan province of China in 1998 and 2005, respectively, and a high proportion of Streptococcal Toxic Shock Syndrome (STSS) which is rare at home and abroad appears in patients. The patients have extremely violent disease course, can have the manifestations of damaged heart and liver function, damaged blood cells, hematopoietic system inhibition, meningitis, damaged auditory nerve and other multiple organ functions, and die within 1 to 3 days of disease^[1-2]. The high pathogenicity and high mortality characteristics exhibited by the S.suis2 epidemic strain, a new zoonotic infectious disease pathogen, have become the focus of public health of worldwide concern^[2-4]And the corresponding anti-infection treatment can be carried out as early as possible, so that the death rate of the patient can be greatly reduced. So far, cerebrospinal fluid and peripheral blood culture are still gold standards for judging infection of S.suis2 of people, but blood culture is easily influenced by multiple factors such as anticoagulant, antibacterial drugs, specimen collection time and culture methods, and the positive rate is often low, so that establishment of a reliable detection method is particularly important for symptomatic treatment of S.suis2 infection. Therefore, the protein structure of S.suis2 is researched, the specific peptide fragment is screened, and a method for quickly diagnosing S.suis2 infection is established, so that the method has important clinical significance for emergency treatment of early infection.

Sao protein (Surface antigen one), a protein discovered by Li and the like in the large-scale research process of searching for functional proteins related to S.suis2 strong pathogenicity^[5]. It is anchored to the cell wall surface by the C-terminal LPVTG motif and is highly conserved^[5]. Immunity electron microscopeExperiments prove that Sao is a protein widely distributed on the surface of thalli, and a Sao protein specific antibody can perform specific reaction with various isolates of S.suis2^[5]. The Sao protein was shown to be a potent antigen expressed during s.suis2 infection. It can be seen that the Sao protein has a great potential to become a screening molecule for s.suis2 infection. Early work in a laboratory shows that the purification difficulty of the recombinant Sao protein is high, and the Sao protein is unstable with a coefficient of instability of 42.24 which is higher than a threshold value of 40 through the primary structure analysis of the Sao protein. Similar degradation problems were encountered during the experiment: protein bands still appear during the elution of high-concentration imidazole in the protein purification process, and are caused by the degradation of recombinant Sao protein (figure 1). Therefore, 4 protease inhibitors PMSF, Pepsatin, Leupepptin and Aprotinin are required to be added when the recombinant Sao protein is stored, and the recombinant Sao protein can be stabilized at 4 ℃ for only one week and can be stabilized at-20 ℃ for only 6 months. These factors have hampered the further development of recombinant Sao proteins as detection markers.

Less immunological information analysis about the Sao protein is reported at present, and no detection marker research based on the immunodominant epitope of the Sao protein is reported. If dominant epitopes of S.suis2 infection specific expression can be screened and corresponding auxiliary diagnosis kits are developed, rapid auxiliary diagnosis of S.suis2 infection can be realized, and death caused by untimely diagnosis of S.suis2 infection can be greatly reduced.

Disclosure of Invention

The invention aims at solving the technical problems and provides a detection marker related to rapid auxiliary diagnosis of S.suis2 infection and based on the immunodominant epitope of the Sao protein.

The second purpose of the invention is to provide the application of the immune dominant epitope of the Sao protein in the preparation of a rapid auxiliary diagnosis kit for S.suis2 infection.

A third object of the present invention is to provide a rapid auxiliary diagnostic kit for s.suis2 infection.

The purpose of the invention is realized by the following technical scheme:

suis2 infection and Sao protein are combined to be wide on the surface of thalli by utilizing the existing network resources and bioinformatics toolsThe pan-distribution characteristics, especially the specific antibody of the Sao protein, can react with various isolates of S.suis2 specifically^[5]According to the important theory, 10 peptide fragments are preliminarily designed and synthesized. Respectively taking 10 synthetic peptides as coating antigens and Sao polyclonal antiserum (Anti-Sao) as a primary antibody, and screening the synthetic peptides with immunodominance by an indirect ELISA method. We found that 1 of these synthetic peptides Sao_355～384Can react with Anti-Sao strongly, which indicates that Sao_355～384An immunodominant antibody response was induced in anti-s.suis 2 infection. There is no literature report on this epitope. Subject group further includes Sao_355～384For detecting antigen, different source sera are taken as primary antibodies, and are respectively taken as an experimental group by S.suis2 infected human sera, a control group by other bacteria (Klebsiella pneumoniae, Escherichia coli, staphylococcus epidermidis and the like) infected human sera and a negative control group by normal human negative sera, so as to complete indirect ELISA detection. Data show that the synthetic peptide Sao_355～384Only reacts strongly with serum of human after S.suis2 infection, but does not react with serum of other bacteria after infection and normal human serum. The results confirm that Sao_355～384The specific antibody can be captured in human peripheral blood after S.suis2 infection, and can be used as a detection marker of S.suis2 infection.

In a whole antigen, an epitope is the smallest unit that exerts an immunological effect. To obtain Sao_355～384The subject synthesizes Sao, a peptide_355～384Coupled with carrier protein to obtain corresponding antiserum Anti-Sao_355～384. Further, the antiserum was used to cover Sao_355～384The binding force of the full-length truncated peptide was examined to determine Sao_355～384The core sequence of (1). We have found that the epitope Sao_355～372And Anti-Sao_355～384The binding capacity of (c) is strongest. The core sequence Sao at present_355～372There is no relevant literature report. Also, we use Sao_355～372For antigen detection, indirect ELISA was performed using sera from different sources as an antibody (sera from the same sources as above). Data show that the synthetic peptide Sao_355～372Only strongly reacts with human serum after s.suis2 infection,but does not react with the serum after other bacteria infection and the serum of normal people. Show Sao_355～372Is indeed Sao_355～384Core epitope of (1), and Sao_355～384The antibody has binding capacity with similar strength, can capture specific antibodies in human peripheral blood after S.suis2 infection, and can become a more ideal detection marker.

Therefore, the present subject has not only found a novel epitope of Sao protein, Sao_355～384And the core epitope Sao thereof is revealed_355～372And further evaluated the ability of both as markers for detection of s.suis2 infection.

Synthetic peptide Sao related to S.suis2 infection_355～384The amino acid sequence of the synthetic peptide is as follows:

SEKQMPSVVNENAVTPEKQMTNKENDNIET(SEQ ID NO.1)。

the synthetic peptide is a peptide segment containing 30 amino acids and can strongly react with human serum infected by Anti-Sao and S.suis 2.

Synthetic peptide Sao related to S.suis2 infection_355～372. The amino acid sequence of the synthetic peptide is as follows:

SEKQMPSVVNENAVTPEK(SEQ ID NO.2)。

the synthetic peptide is a peptide segment containing 18 amino acids and can strongly react with human serum after Anti-Sao and S.suis2 infection.

Synthetic peptide Sao_355～384Core sequence Sao_355～372The antigen is used as a coating antigen in the preparation of a S.suis2 infection rapid auxiliary diagnosis kit.

A rapid auxiliary diagnosis kit for S.suis2 infection is used for detecting specific antibodies in serum of a human after S.suis2 infection. The rapid auxiliary diagnostic kit contains a detection marker Sao_355～384。

A rapid auxiliary diagnosis kit for S.suis2 infection is used for detecting specific antibodies in serum of a human after S.suis2 infection. The rapid auxiliary diagnostic kit contains a detection marker Sao_355～372。

The rapid auxiliary diagnostic kit also comprises a reagent commonly used for ELISA detection. Such as coating solution, bovine serum albumin V, PBS buffer solution, HRP-goat anti-mouse polyclonal serum, stop solution, TMB color development solution, etc., and may also contain negative and positive control substances.

Has the advantages that:

the invention provides a self-designed synthetic peptide, and the purity of two synthetic peptides can be respectively 94.92% and 92.27% by high performance liquid chromatography (figure 2). The synthetic peptide is white powdery freeze-dried powder, and has stable property and can be stored for years at the temperature of-20 ℃. Experiments prove that the synthetic peptide can capture specific antibodies in human peripheral blood after S.suis2 infection, and can be used as a coating antigen to be applied to a rapid auxiliary diagnosis kit for S.suis2 infection. The invention provides a new idea for rapid auxiliary diagnosis of S.suis2, can reduce death caused by untimely diagnosis of S.suis2 infection, and has potential good clinical application value.

Drawings

FIG. 1Sao protein Ni-IDA affinity chromatography purification detection

1: induced supernatant; 2: discharging liquid; 3: 30mM imidazole rinse; 4: 60mM imidazole rinse; 5:90mM imidazole rinse; 6-9: 250mM imidazole eluent; arrow head: the recombinant Sao protein degrades to cause the hybrid protein band.

FIG. 2 Indirect ELISA method for screening immunodominant B-cell epitope peptide of Sao

FIG. 3Sao_355～384Binding to human serum from different sources

1-23 are negative serum of normal people; 24 is human serum after staphylococcus epidermidis infection; 25 is human serum after enterococcus faecium infection; 26 is human serum after Klebsiella pneumoniae infection; 27 is human serum after escherichia coli infection; 28-30 are sera of different people after streptococcus suis infection.

FIG. 4Anti-Sao_355～384Serum titer

FIG. 5 Indirect ELISA screening of Sao_355～384Core epitope of (2)

FIG. 6Sao_355～372Binding to human serum from different sources

Detailed Description

Example 1: 05ZYH 33-derived Sao sequence information and Linear B cell epitope prediction

1.1 clear Sao protein sequence: the total length of the Sao protein is 580 amino acids, wherein, the amino acids at 1-29 are signal peptides, and the specific sequence is shown in SEQ ID NO. 3.

1.2Sao protein immune informatics parameter Prediction, namely predicting Hydrophilicity, flexibility, Surface Accessibility and β folding of Sao protein by using a Parker hydrophicality Prediction tool, a Karplus & Schulz Flexibityprediction tool and a Chou & Fasman Beta-Turnprediction tool under the Antibody epitope Prediction in an IEDB website, setting a threshold value, and summarizing and analyzing 4 immune informatics parameter Prediction results.

1.3Sao protein B cell epitope prediction: predicting by using three linear B cell epitope prediction tools (Bepipred, COBrepro and ABCPred), summarizing and comparing the B cell epitopes predicted by the three methods, taking the overlapped B cell epitopes as candidate B cell epitopes, and screening the Sao protein B cell epitope peptide by combining the prediction result of the immune informatics parameters.

1.4 results of the experiment

The prediction results of the epitope prediction tools are summarized and compared, 10B cell epitope peptides are finally screened by combining the prediction results of the immune informatics parameters, and are synthesized by assistance of Gill Biochemical (Shanghai) Co. The basic sequence is shown in Table 1.

Table 1: sao protein 10 candidate B cell epitope peptide amino acid sequence information

Example 2: method for screening Sao protein immunodominance linear B cell epitope peptide by indirect ELISA method

2.1 preparation of Anti-Sao

Taking SPF grade 6-8 week female BALB/c mice. First immunization: fully emulsifying the purified rSao protein (the preparation method is shown in Wangjing, Limin, Liuwenjing, et al. Sao protein polyclonal antibody preparation identification and whole blood sterilization promotion [ J ]. Chinese public health, 2014,30(3):364 and 367) with Freund complete adjuvant, and performing subcutaneous multi-point injection on the abdomen, wherein the immunization dose is 100 mu g/mouse; 2 nd immunization: after 2 weeks of first immunization, rSao protein and Freund incomplete adjuvant are completely emulsified and injected into multiple points under the skin, and the immunization dose is 100 mu g/mouse; the 3 rd immunization was performed 2 weeks after the 2 nd immunization, and the dose and method were the same as those of the 2 nd immunization; and (3) boosting immunity: 2 weeks after the 3 rd immunization, the unemulsified rSao protein was injected intraperitoneally at a dose of 100. mu.g/mouse. Blood is taken from the retroorbital venous plexus of the mouse after 7 days of boosting immunization, the separated serum is Anti-Sao, and the titer of the Anti-Sao is detected by indirect ELISA.

2.2 determining the B cell linear epitope peptide with dominant response according to the response level of different B cell epitope peptides and Anti-Sao. The indirect ELISA procedure was as follows:

2.2.1 antigen coating: in order to determine the B cell linear epitope peptide of the Sao dominant response, 10 candidate B cell linear epitope peptides, negative control protein BSA and positive control rSao protein are respectively coated in an ELISA plate, and then Anti-Sao is used for detection. Antigen coating concentrations were adjusted with coating solution (50mM sodium carbonate/sodium bicarbonate, pH 9.6) to make 2 replicates per antigen. Adjusting the concentrations of the purified rSao protein and B cell epitope peptide to 1 mu g/ml, and coating the ELISA plate at 100 mu l/hole overnight at 4 ℃;

2.2.2 blocking: washing the plate with Phosphate buffer solution (Phosphate Buffered Saline Tween-20, PBST) containing Tween-20 for 3 times, spin-drying, adding 200 μ l of blocking solution (3% BSA solution) into each well, and blocking at 37 deg.C for 2 h;

2.2.3 addition of Primary antibody: PBST plate washing 3 times, spin-drying, Anti-Sao according to 1: diluting with 5000, adding 100 μ l/well of enzyme label plate, and incubating at 37 deg.C for 1 h;

2.2.4 addition of secondary antibody: PBST plates were washed 3 times, spun dry, HRP labeled goat anti-mouse IgG was run according to 1: diluting with 4000, adding an enzyme label plate into 100 mu l/hole, and incubating for 1h at 37 ℃;

2.2.5 color development: washing the PBST for 3 times, spin-drying, adding 100 μ l/hole of TMB color development solution into the ELISA plate, and developing in dark for 10 min;

2.2.6 termination reaction: adding 100 mul/hole of stop solution into the enzyme label plate, and stopping reaction;

2.2.7 detection: and detecting the absorbance (A) value at 450nm by using an enzyme-labeling instrument, wherein the sample to be detected/negative control (P/N) is more than or equal to 2.1 and is positive.

2.3 results of the experiment

At OD_450nmEpitope peptide Sao_355～384The absorbance value of the reagent is obviously higher than that of negative control protein BSA (P)<0.0001), the absorbance value of which is significantly different from that of other epitope peptides (P)<0.0001), Sao can be seen_355～384Is an immunodominant epitope peptide of Sao. The results are shown in FIG. 2.

Example 3: sao_355～384Detection of s.suis2 infection

3.1 with Sao_355～384For detecting antigen, different source sera are taken as primary antibodies, and are respectively taken as an experimental group by S.suis2 infected human sera, a control group by other bacteria (Klebsiella pneumoniae, Escherichia coli, staphylococcus epidermidis and the like) infected human sera and a negative control group by normal human negative sera, so as to complete indirect ELISA detection. The method comprises the following specific steps:

3.1.1 antigen coating: encapsulation of synthetic peptide Sao in ELISA plates_355～384. Antigen coating concentrations were adjusted with coating solution (50mM sodium carbonate/sodium bicarbonate, pH 9.6) to make 2 replicates per antigen. The coating concentration and conditions are the same as 2.2.1;

3.1.2 blocking: the sealing time of the sealing liquid is the same as that of the sealing liquid for 2.2.2;

3.1.3 addition of Primary antibody: primary antibodies are divided into three groups according to their sources. The first group was experimental, 3 total sera from s.suis2 infected humans; the second group is other bacteria control group, which is respectively 4 parts of human serum infected by Klebsiella pneumoniae, Escherichia coli, Staphylococcus epidermidis and enterococcus faecium; the third group is a negative control group, which is 23 parts of normal human serum, PBST washes the plate for 3 times, and then spin-dries, and the first antiserum is mixed according to the ratio of 1: diluting at 200, adding an enzyme label plate at 100 mu l/hole, and incubating for 1h at 37 ℃;

3.1.4 addition of secondary antibody: PBST wash plate 3 times, spin dry, HRP labeled goat anti-human IgG according to 1: diluting with 4000, adding an enzyme label plate into 100 mu l/hole, and incubating for 1h at 37 ℃;

3.1.5 the color development and the termination reaction are the same as 2.2.5 and 2.2.6;

3.1.6 detection: and detecting the absorbance (A) value at 450nm by using an enzyme-labeling instrument, wherein the sample to be detected/negative control (P/N) is more than or equal to 2.1 and is positive.

3.2 results of the experiment

Synthetic peptide Sao_355～384Only with s.suis2 infected human serum, but not with other bacteria infected serum, normal human serum, the results are shown in fig. 3.

Example 4: immunodominant B cell epitope peptide Sao_355～384Animal immunization and antiserum collection thereof

4.1 synthetic peptide to be identified Sao_355～384Coupled to KLH protein, female BALB/c mice, 6 weeks old, were further immunized with the aid of Freund's adjuvant. Handing over was done by gill biochemical (shanghai) ltd. The immunization procedure was as follows.

4.1.1 Primary immunization (day 0): sao_355～384-emulsification of KLH conjugate with equal volume of freund's complete adjuvant, 100 μ g/dose, 200 μ l/dose, abdominal subcutaneous multiple injection (3-5 spots, about 50 μ l/spot);

4.1.2 second immunization (day 14): sao_355～384-the KLH conjugate was emulsified with an equal volume of incomplete freund's adjuvant at the same dose as the route of injection shown in 2.1;

4.1.3 third immunization (day 28): sao_355～384-emulsification of KLH conjugate with an equal volume of incomplete freund's adjuvant, 50 μ g/dose, 200 μ l/dose, abdominal subcutaneous multiple injection;

4.1.4 Collection of Anti-Sao_355～384Serum (day 35): performing euthanasia operation on BALB/c mice by adopting a cervical dislocation method, taking blood by adopting a heart blood collection method, centrifuging and packaging.

4.2 results of the experiment are shown in FIG. 4.

Example 5: sao_355～384Screening for core epitopes

5.1 is Sao definition_355～384AgainstThe amino acid sequence design covers Sao_355～384Full length corresponding truncated peptide. The synthesis of the truncated peptide was performed by gill biochemical (shanghai) ltd.

5.2 Indirect ELISA screening of Sao_355～384The core epitope comprises the following specific steps:

5.2.1 antigen coating: the ELISA plate is coated with 5 kinds of truncated peptides, negative control protein BSA and positive control Sao_355～384. Antigen coating concentrations were adjusted with coating solution (50mM sodium carbonate/sodium bicarbonate, pH 9.6) to make 2 replicates per antigen. The coating concentration and conditions are the same as 2.2.1;

5.2.2 blocking: the sealing time of the sealing liquid is the same as that of the sealing liquid for 2.2.2;

5.2.3 adding primary antibody: PBST plate washing 3 times, spin-drying, Anti-Sao_355～384Serum was measured according to 1: diluting with 4000, adding an enzyme label plate into 100 mu l/hole, and incubating for 1h at 37 ℃;

5.2.4 addition of secondary antibody: PBST plates were washed 3 times, spun dry, HRP labeled goat anti-mouse IgG was run according to 1: diluting with 4000, adding an enzyme label plate into 100 mu l/hole, and incubating for 1h at 37 ℃;

5.2.5 the color development and the termination reaction are the same as 2.2.5 and 2.2.6;

5.2.6 detection: and detecting the absorbance (A) value at 450nm by using an enzyme-labeling instrument, wherein the sample to be detected/negative control (P/N) is more than or equal to 2.1 and is positive.

5.2 results of the experiment

5 truncated peptides were analyzed and screened, and the numbers and amino acid sequences are shown in Table 2. Each truncated peptide was conjugated to Anti-Sao_355～384The reaction conditions of (2) are shown in FIG. 5.

Table 2: sao_355～384Corresponding truncated peptide amino acid sequence information

Example 6: sao_355～372Detection of s.suis2 infection

6.1 with Sao_355～372For detecting antigen, different source sera are used as primary antibody, and S.suis2 infected human sera are used as experimental group, other bacteria (Klebsiella pneumoniae, Escherichia coli, Staphylococcus epidermidis, etc.)And (4) taking the infected serum as a control group and taking the negative serum of a normal person as a negative control group to finish indirect ELISA detection. The specific procedure was as described in example 3.

6.2 results of the experiment

Synthetic peptide Sao_355～372Only reacts strongly with serum of human after S.suis2 infection, but does not react with serum of other bacteria after infection and normal human serum. The results are shown in FIG. 6.

While the preferred embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that the invention is not limited thereto, and that various changes and modifications may be made without departing from the spirit of the invention, and the scope of the appended claims is to be accorded the full range of equivalents.

Sequence listing

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<120> synthetic peptide for detecting S.suis2 infection and use thereof

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Lys Asn Thr Ile Ile Ser Ala Lys Gln Pro Asp Gly Gly Gln Ala Thr

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Ser Lys Ala Val Asn Val Lys Ile Pro Ala Val Val Arg Leu Phe Gly

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Arg Glu Leu Leu Glu Asn Glu Phe Lys Phe Glu Leu Arg Glu Ala Asn

65 70 75 80

Gly Glu Glu Leu Pro Val Leu Asp Thr Ala Gln Asn Thr Lys Glu Gly

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Gln Val Arg Phe Lys Asn Leu Ser Phe Asp Lys Pro Gly Lys Tyr Trp

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Tyr Thr Ile Ser Glu Val Lys Asp Glu Leu Gly Gly Ile Glu Tyr Asp

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Leu Gln Ala Met Ile Glu Phe Ile Asp Asn Asp Asn Val Phe Asn Asn

145 150 155 160

Phe Tyr Thr Pro Ala Pro Ala Ala Ala Ser Leu Ser Ile Lys Lys Val

165 170 175

Leu Glu Gly Arg Thr Leu Asn Thr Gly Glu Phe Glu Phe Val Leu Lys

180 185 190

Asn Glu Lys Gly Asp Glu Ile Glu Lys Val Ser Asn Gln Ala Asp Gly

195 200 205

Ser Val Asn Phe Ser Ala Leu Thr Phe Thr Lys Glu Gly Thr Tyr Thr

210 215 220

Tyr Thr Val Ser Glu Val Asp Gly Gly Leu Gly Asp Ile Ile Tyr Asp

225 230 235 240

Lys Ser Asp Ile Lys Ala Thr Val Thr Val Lys Asp Asn Asn His Gly

245 250 255

Gln Leu Val Ser Thr Val Thr Tyr Glu Asn Ser Asp Gln Ile Phe Glu

260 265 270

Asn Ile Leu Asn Pro Gly Lys Leu Ile Ala Pro Thr Thr Asp Ser Val

275 280 285

Ile Thr Asp Asn Glu Val Ser Lys Glu Ala Met Thr Gly Lys Glu Lys

290 295 300

Gly Asn Ile Glu Pro Leu Lys Glu Gln Ile Ala Asn Glu Glu Lys Asp

305 310 315 320

Asn Ile Glu Ala Ser Glu Lys Gln Met Pro Ser Ile Val Asn Asp Met

325 330 335

Val Val Thr Pro Glu Lys Gln Met Thr Asn Lys Glu Asn Asp Lys Val

340 345 350

Val Ile Ser Glu Lys Gln Met Pro Ser Val Val Asn Glu Asn Ala Val

355 360 365

Thr Pro Glu Lys Gln Met Thr Asn Lys Glu Asn Asp Asn Ile Glu Thr

370 375 380

Ser Glu Lys Gln Met Pro Ser Val Val Asn Glu Asn Ala Val Thr Pro

385 390 395 400

Glu Lys Gln Met Thr Asn Lys Glu Lys Asp Asn Ile Glu Thr Ser Glu

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Lys Gln Met Pro Ser Ile Val Asn Asp Met Val Val Thr Pro Gln Glu

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Gln Met Ala Asn Lys Glu Asn Asp Lys Val Val Ile Ser Glu Lys Gln

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Ala Asn Lys Glu Asn Asp Lys Val Glu Thr Ser Glu Lys Gln Met Pro

465 470 475 480

Val Asn Glu Lys Asp Asn Ala Val Thr Pro Glu Lys Gln Met Ala Asn

485 490 495

Lys Glu Lys Glu Asn Ile Glu Thr Ser Lys Lys Gln Ile Pro Val Asn

500 505 510

Glu Asn Asn Gln Asn Gly Thr Val Glu Glu Asn Ser Asn Thr Lys Pro

515 520 525

Thr Thr Glu Lys Thr Asp Lys Gln Glu Thr Ser Thr Phe Lys Thr Glu

530 535 540

Thr Ala Lys Gln Ile Leu Pro Val Thr Gly Glu Lys Gly Ser Leu Trp

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Leu Leu Thr Ser Gly Ile Ile Gly Leu Ala Ile Ala Leu Phe Thr Arg

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Lys Arg Lys Leu

580

Claims

1. Synthetic peptide Sao for detecting S.suis2 infection_355～384The peptide is characterized in that the amino acid sequence of the synthetic peptide is shown as SEQ ID NO. 1.

2. The synthetic peptide of claim 1, Sao_355～384The kit is applied to preparation of a rapid auxiliary diagnosis kit for S.suis2 infection.

3. Synthetic peptide Sao for detecting S.suis2 infection_355～372The peptide is characterized in that the amino acid sequence of the synthetic peptide is shown as SEQ ID NO. 2.

4. The synthetic peptide of claim 3, Sao_355～384The kit is applied to preparation of a rapid auxiliary diagnosis kit for S.suis2 infection.

5. A kit for rapid auxiliary diagnosis of S.suis2 infection, characterized in that it comprises the synthetic peptide Sao of claim 1_355～384。

6. Suis2 infection rapid auxiliary diagnostic kit, characterized in that the kit contains the synthetic peptide Sao of claim 3_355～372。

7. The kit for rapid auxiliary diagnosis of S.suis2 infection according to claim 5 or 6, wherein the kit further comprises reagents commonly used in ELISA detection: coating solution, bovine serum albumin V, PBS buffer solution, HRP-goat anti-mouse polyclonal serum, stop solution and TMB color development solution.

8. The s.suis2 infection rapid-aided diagnosis kit according to claim 5 or 6, characterized in that the rapid-aided diagnosis kit further comprises negative and positive controls.