Disclosure of Invention
The invention aims to prepare tuberculosis vaccines.
The invention firstly protects the application of Rv1485 protein in preparing tuberculosis detection reagent, tuberculosis vaccine or antitubercular drug.
The Rv1485 protein may be a 1) or a 2) or a 3):
a1 Protein composed of amino acid sequences shown in sequence 2 in a sequence table;
a2 A fusion protein obtained by connecting a label with the N end or/and the C end of the protein shown in the sequence 2 in the sequence table;
a3 A protein which is obtained by substituting and/or deleting and/or adding one or more amino acid residues for the amino acid sequence shown in the sequence 2 in the sequence table and has the same function as the protein in the a 1).
Wherein, the sequence 2 in the sequence table consists of 344 amino acid residues.
In order to facilitate purification of the protein of a 1), a tag as shown in Table 11 may be attached to the amino-terminal or carboxyl-terminal of the protein shown in sequence 2 in the sequence listing.
TABLE 11 sequence of tags
Label (Label)
|
Residues
|
Sequence(s)
|
Poly-Arg
|
5-6 (usually 5)
|
RRRRR
|
FLAG
|
8
|
DYKDDDDK
|
Strep-tag II
|
8
|
WSHPQFEK
|
c-myc
|
10
|
EQKLISEEDL |
The protein of the above a 3), wherein the substitution and/or deletion and/or addition of one or more amino acid residues is a substitution and/or deletion and/or addition of not more than 10 amino acid residues.
The protein in the a 3) can be synthesized artificially or can be obtained by synthesizing the coding gene and then biologically expressing.
The gene encoding the protein in the above a 3) can be obtained by deleting one or several amino acid residues from the gene encoding the protein, and/or performing one or several base pair missense mutation, and/or ligating the coding sequence of the tag shown in Table 11 at the 5 'end and/or 3' end thereof.
The invention also protects a tuberculosis detection reagent, which can comprise at least one of b 1) to b 3):
b1 The Rv1485 protein;
b2 A nucleic acid molecule encoding said Rv1485 protein;
b3 A recombinant protein expressed by a recombinant bacterium comprising a nucleic acid molecule encoding said Rv1485 protein.
In the tuberculosis detection reagent, b 1) or b 2) or b 3) may be an active ingredient.
The invention also protects a T-SPOT.TB kit or an X.DOT-TB kit containing the tuberculosis detection reagent.
The kit may also contain a capture antibody and/or a detection antibody. The capture antibody may be a mouse monoclonal antibody against human or animal IFN-gamma. The detection antibody may be another mouse monoclonal antibody against a different epitope of human or animal IFN-gamma. The animal can be mouse, rat, rabbit, sheep, horse.
Any of the above kits may further comprise a positive standard and/or a negative standard. The positive standard may be a tuberculosis non-specific stimulating antigen. The negative standard may be an antigen-free cell culture broth. The tuberculosis non-specific stimulatory antigen may be phytohemagglutinin, PHA.
Any of the above kits may further comprise a readable carrier described as follows: when the number of SFCs detected by ESAT6/CFP10 exceeds a certain standard (not less than 6 for the T-SPOT. TB kit and not less than 11 for the X.DOT-TB kit), the test reading is considered positive for MTB infection; otherwise the test reading is considered negative for MTB infection.
The invention also protects a tuberculosis vaccine, which can comprise at least one of b 1) to b 3):
b1 The Rv1485 protein;
b2 A nucleic acid molecule encoding said Rv1485 protein;
b3 A recombinant protein expressed by a recombinant bacterium comprising a nucleic acid molecule encoding said Rv1485 protein.
In the tuberculosis vaccine, b 1) or b 2) or b 3) may be an active ingredient.
The invention also protects a tuberculosis vaccine which can be obtained by modifying recombinant BCG containing the Rv1485 protein.
The invention also provides antitubercular medicaments, which may include antibodies that bind to the Rv1485 protein.
In the above antitubercular drug, the antibody may be an antibody prepared using the Rv1485 protein as an immunogen.
In the above antitubercular drug, the antibody may be A1) or A2).
A1 Polyclonal antibodies prepared by immunizing animals (such as mice, rats, rabbits, sheep, and humans) with the Rv1485 protein as an immunogen.
A2 The Rv1485 protein is used as an immunogen to immunize animals (such as mice, rats, rabbits, sheep and humans) and the hybridoma technology or the DNA recombination technology is adopted to prepare the monoclonal antibody. The monoclonal antibody may be a humanized monoclonal antibody.
In the antitubercular drug, the antibody may be an active ingredient.
The antitubercular drug may specifically consist of any of the antibodies described above.
Experiments prove that the Rv1485 protein induces effective Th1 type humoral and cellular immune response, is beneficial to the control of tuberculosis, and can protect hosts from being affected by mycobacterium tuberculosis. The invention has important application value.
Detailed Description
The following examples facilitate a better understanding of the present invention, but are not intended to limit the same.
The experimental methods in the following examples are conventional methods unless otherwise specified.
The test materials used in the examples described below, unless otherwise specified, were purchased from conventional biochemical reagent stores.
The quantitative tests in the following examples were all set up in triplicate and the results averaged.
The Mycobacterium bovis BCG strain is a product of ATCC company, catalog number 35734. The Mycobacterium bovis BCG strain is hereinafter referred to as BCG.
Mycobacterium tuberculosis H37Rv strain is provided by Beijing thoracic hospital affiliated to university of capital medical science. Mycobacterium tuberculosis H37Rv strain hereinafter referred to as Mycobacterium tuberculosis.
Coli Rosetta (DE 3) is a product of Beijing full gold biotechnology Co. LB liquid medium is a product of the company oxoid, UK. The X.DOT-TB kit is a product of Guangdong body Bikang Biotechnology Co.
The T-SPOT.TB kit is a product of Oxford Immunotec, inc. of England. Both the IFN-gamma monoclonal capture antibody and the IFN-gamma detection antibody are components of the T-SPOT.TB kit.
Mycobacterium tuberculosis medium: an aqueous solution containing 0.5% (v/v) glycerol, 0.05% (v/v) Tween-80 and 10% (v/v) liquid Middlebrook7H 9 medium. Liquid Middlebrook7H 9 medium is a product of BD company.
MedieBurk7H10 medium: middlebrook7H10 medium containing 10% (v/v) OADC. Middlebrook7H10 medium is a product of BD company.
In the examples below, statistical analysis was performed using a graphic pad prism (version 6) and Excel. Data are expressed as ± SEM. Determining the statistical significance of the comparison data between groups using one-way analysis of variance (ANOVA), P <0.05; * P <0.01; * P <0.001. The significance of the inter-sample differences was analyzed using paired t-test, with statistical treatment at P <0.05.
IFN-y release assays in the examples below were performed using either the X.DOT-TB kit or the T-SPOT.TB kit.
The procedure for detection using the T-SPOT. TB kit was as follows:
(1) Blood samples were taken and PBMC were collected using Ficoll-Paque density gradient centrifugation.
(2) A96-well plate was used, 100. Mu.L of IFN-. Gamma.monoclonal capture antibody was added to each well, and coated overnight at 4 ℃.
(3) After the completion of step (2), the 96-well plate was taken, the liquid phase was discarded, washed twice (1 min each time) with PBS buffer at pH7.4 and 0.01M, and then the plate was dried.
(4) After completion of step (3), 200. Mu.L of PBS buffer, pH7.4, containing 2% (v/v) BSA, 0.01M was added to each well of the 96-well plate, and incubated at 37℃for 1 hour.
(5) After the step (4) is completed, taking the 96-well plate, discarding the liquid phase, adding RPMI1640 culture solution, and washing once.
(6) Taking the 96-well plate finished in the step (5), and adding 50 mu L of an aqueous solution of the mycobacterium tuberculosis protein (the concentration is 200 pmol) into each detection well; 50. Mu.L of an aqueous solution (200 pmol) of the fusion protein CFP10-ESAT6 was added to each control well; add 50. Mu.L of serum-free medium to each negative control well; mu.L of phytohemagglutinin solution (phytohemagglutinin dissolved in AIM V) was added to each positive control well TM Medium serum-free Medium was obtained at a concentration of 200 pmol).
(7) After completion of step (6), 100. Mu.L of PBMC (about 2.5X10) collected in step (1) was added to each well 6 Individual lymphocytes).
(8) After step (7) is completed, the 96-well plate is placed in an incubator at 37 ℃ with 5% CO 2 Culturing for 18-20h.
(9) After the step (8) is completed, taking the 96-well plate, discarding the supernatant, adding 200 mu L of precooled ice water, firstly placing at-20 ℃ for 5min (aiming at cell lysis), and then placing at 4 ℃ for 5min (aiming at cell lysis).
(10) After completion of step (9), the 96-well plate was taken, the supernatant was discarded, washed 7 times with washing solution (200. Mu.L of washing solution each time, 1min each time), and patted dry.
(11) After completion of step (10), 100. Mu.L of IFN-gamma detection antibody dilution (made up of 999 parts by volume of pH7.4, 0.01M PBS buffer and 1 part by volume of IFN-gamma detection antibody) was added to each well of the 96-well plate, and incubated at 37℃for 1 hour.
(12) After the completion of step (11), the 96-well plate was taken, the supernatant was discarded, washed 5 times with washing solution (200. Mu.L of washing solution was added each time, and washing was performed for 1min each time), and the plate was dried.
(13) After completion of step (12), 100. Mu.L of a dilution of the alkaline phosphatase-labeled streptavidin (prepared by mixing 999 parts by volume of pH7.4, 0.01M PBS buffer and 1 part by volume of alkaline phosphatase-labeled streptavidin) was added to each well, and incubated at 37℃for 30min.
(13) After completion of step (12), the 96-well plate was taken, the supernatant was discarded, washed 5 times with washing solution (200. Mu.L of washing solution was added each time, and washing was performed for 1min each time), and the plate was dried.
(14) After the step (13) is completed, 100 mu L of BCIP/NBT substrate solution is added into each well of the 96-well plate, and the light is turned off and color development is carried out for 7-15min at room temperature.
(15) After completion of step (14), the 96-well plate was taken, washed 3 times with distilled water (for the purpose of stopping the reaction), and then the 96-well plate was put in an oven at 37 ℃ for drying.
(16) After step (15) is completed, the 96-well plates are counted using an immunoblotter S6 spot reader (CTL, cleveland, ohio); the results were analyzed using prism graphics software.
The amino acid sequence of the Rv1705c protein is shown as a sequence 1 in a sequence table.
The amino acid sequence of the Rv1485 protein is shown as a sequence 2 in a sequence table.
Example 1 high throughput purification of Mycobacterium tuberculosis 1781 protein and detection of its antigenicity
The inventors of the present invention used a high throughput method system to identify MTB protein antigens based on the ability of MTB protein antigens to induce IFN-gamma release from Peripheral Blood Mononuclear Cells (PBMC) isolated from patients with active tuberculosis, and then evaluated the protective effect of MTB protein antigens in BALB/c mice in a model of infection with tuberculosis. The experimental strategy for identifying MTB antigen protein and verifying the protective effect of MTB antigen protein in a model of BALB/c mice infected by tubercle bacillus is shown in FIG. 1.
1. High throughput purification of mycobacterium tuberculosis 1781 protein
1. Construction of recombinant plasmids
Mycobacterium tuberculosis clone library (described in Deng J, bi L, zhou L, guo SJ, fleming J, et al (2014) Mycobacterium tuberculosis proteome microarray for848global studies of protein function and immunogeneticity. Cell Rep 9:2317-2329; the library contains 3404H 37Rv and 437 CDC1551 sequencing ORF clones), each clone and vector pDEST17 were subjected to LR recombination reaction by LR clonase mixture to obtain the corresponding recombinant plasmid.
The vector pDEST17 and LR clonase mixture are both products of Invitrogen.
2. Expression of Mycobacterium tuberculosis proteins
(1) And (3) respectively introducing the recombinant plasmids constructed in the step (1) into escherichia coli Rosetta (DE 3) to obtain corresponding recombinant escherichia coli.
(2) After the step (1) is completed, the recombinant escherichia coli is respectively inoculated to 1mL of LB liquid medium containing 34 mug/mL of chloramphenicol and 100 mug/mL of ampicillin, and the corresponding culture broth 1 is obtained after shaking culture for 4 hours at 37 ℃ and 200 rpm.
(3) After the step (2) is completed, IPTG is respectively added into the culture bacteria liquid 1, so that the concentration of the IPTG in the system is 0.4mM, and then the culture bacteria liquid 2 is obtained after shaking culture for 6 hours at 37 ℃ and 200 rpm.
(4) After the step (3) is completed, the culture bacterial liquid 2 is respectively taken and centrifuged at 6000rpm for 15min, the supernatant is discarded, and the corresponding bacterial bodies are collected.
(5) After the completion of the step (4), the cells were resuspended in EDTA buffer having pH8.0 and 0.05M containing 50mM Tris-HCl, respectively, and then sonicated (sonication parameters: 12000rpm, total 10 min) to obtain a cell disruption solution. The cell disruption solution was centrifuged at 12000rpm for 10min to obtain a cell disruption supernatant and a cell disruption precipitate.
And (3) performing SDS-PAGE on the bacterial cell disruption supernatant and the bacterial cell disruption precipitate obtained in the step (5) respectively.
The experimental results show that each mycobacterium tuberculosis protein exists in inclusion bodies.
3. Purification of Mycobacterium tuberculosis proteins
The experiments were all performed at 4 ℃.
(1) The cells obtained in step 2 (5) were crushed and precipitated, and washed successively with 50mM Tris-HCl buffer, 2% (v/v) DOC-containing EDTA buffer of pH8.0, 0.05M and 1M urea aqueous solution.
(2) After completion of step (1), the suspension was resuspended in 50mM Tris-HCl buffer to give the corresponding resuspension.
(3) After completion of step (2), the sample was washed with EDTA buffer at pH8.0, 1 mM.
(4) After completion of step (3), the resulting solution was dissolved in EDTA buffer of pH8.0 containing 15mM DTT and 8M urea at a concentration of 1mM to obtain a corresponding solution.
(5) After completion of step (4), the solution was dialyzed (water was added very slowly to solution 1 using a pump until solution 1 was diluted 10 times) against solution 1 (pH 10, 200mM Tris-HCl buffer containing 8M urea and 20mM L-Argine) to obtain the corresponding dialysate 1.
(6) After completion of step (5), dialysate 1 was dialyzed against solution 2 (pH 8.0 containing 20mM NaCl, 20mM Tris-HCl buffer) to give the corresponding dialysate 2.
The dialysate 2 was subjected to SDS-PAGE, respectively. Detection kit using GC endotoxin (Xiamen Limulus reagent Biotech Co., ltd.) the product of (2) to detect the purity of the corresponding Mycobacterium tuberculosis protein in each dialysate 2.
The results show that the purity of the corresponding mycobacterium tuberculosis proteins in the dialysate 2 is higher.
4. Renaturation
After step 3, dialysate 2 was taken separately and purified using standard protein denaturation and renaturation techniques to yield 1781 Mycobacterium tuberculosis proteins (including 1728H 37Rv and 53 CDC1551 proteins).
To demonstrate that the Mycobacterium tuberculosis protein purified using this strategy is equivalent to the protein purified after soluble expression, the inventors of the present invention evaluated the properties of Mycobacterium tuberculosis protein obtained in step 4 and commercial CFP10 purified recombinant CFP10 (Rv 3874) using IFN-gamma release assay. The results are shown in FIG. 2 (top panel is T-SPOT. TB kit, bottom panel is X.DOT-TB kit). The results showed that the results of the Mycobacterium tuberculosis protein obtained in step 4 and the recombinant CFP10 (Rv 3874) purified by commercial CFP10 were substantially identical, and this result suggests that the denatured/renatured protein can be used for antigen screening.
The above results indicate that the inventors of the present invention were able to purify 1781 proteins (1728H 37Rv and 53 CDC1551 proteins) to the appropriate standard for further analysis (> 80% purity and concentration of not less than 0.5 mg/mL). The molecular weight and purity of the proteins were assessed by SDS-PAGE (see Table 1 for partial proteins). Comparison of the functional class analysis of 1728 proteins (using the tuberculosis list) with the distribution of the entire proteome among the functional classes revealed that the 1781 proteins evaluated here were essentially randomly selected, and this subset was considered to be a good representation of the entire proteome. Over-expression of proteins and under-expression of cell wall and cellular process proteins in the intermediary metabolic and respiratory protein classes may reflect differences between proteins in terms of ease of purification.
TABLE 1
Rv No.
|
Gene name
|
Predicted molecular weight (kDa)
|
Actual molecular weight (kDa)
|
Rv1705c
|
PPE22
|
38.444
|
41
|
Rv1485
|
hemZ
|
37.144
|
45 |
2. Antigenic detection of mycobacterium tuberculosis 1781 protein
1. Collection of clinical samples
Blood samples 2803 of patients with tuberculosis (determined specifically based on clinical symptoms, chest X-ray film, sputum smear microscope, bacteria culture results, IFN-. Gamma.ELISPOT test results and contact history) and 167 of healthy donors "clinically free from significant active tuberculosis symptoms and confirmed as tuberculosis negative by PPD test and IFN-. Gamma.ELISPOT test" were collected, respectively.
2. IFN-gamma ELISPOT detection
During Mycobacterium tuberculosis infection, T cells react to Mycobacterium tuberculosis antigens and play an important role in host-pathogen interactions. T cells are sensitized by mycobacterium tuberculosis antigens, and activated T cells, including cd4+ and cd8+ T cells, release IFN- γ when stimulated in vitro by different mycobacterium tuberculosis specific antigens, the levels of which reflect the intensity of the immune response induced by a given antigen. IFN-gamma release assays (ELISPOT or ELISA methods) are used in the clinical detection of latent Mycobacterium tuberculosis infection and as an aid in the diagnosis of active tuberculosis. Here, the 1781 Mycobacterium tuberculosis proteins obtained above were screened using the commercial IFN-. Gamma.ELISPOT method to assess the ability of each protein to stimulate IFN-. Gamma.release from PBMC derived from suspected tuberculosis patients.
The commercial IFN-. Gamma.ELISPOT assay involves antibody-based detection of IFN-. Gamma.release in response to the nuclear specific antigens ESAT6 and CF10, the results being reported as the number of spot forming cells, i.e., the number of IFN-. Gamma.producing lymphocytes detected. When the number of SFCs detected by ESAT6/CFP10 exceeded a certain standard (. Gtoreq.6 for the T-SPOT.TB kit and (. Gtoreq.11 for the X.DOT-TB kit), the test reading was considered positive for MTB infection. The test results may be compared to the final clinical diagnosis (or microbial culture results, known as the "gold standard" for tuberculosis diagnosis) to determine the sensitivity and specificity of the analysis.
The inventors of the present invention first conducted a rough primary screening in which PBMC samples from 8 suspected tuberculosis patients (including those who were ultimately diagnosed with active tuberculosis and those who were ultimately diagnosed with nontuberculous tuberculosis) were stimulated with ESAT6/CFP10 (control) and purified mycobacterium tuberculosis, respectively. Mycobacterium tuberculosis proteins were tested for IFN-gamma release levels using a commercial ELISPOT assay (T.SPOT-TB kit or X-DOT.TB kit, with separate clinical evaluations showing that these two commercial kits are essentially identical and are used interchangeably; see Table 3 and FIG. 3). While most of the MTB proteins tested did not induce detectable IFN- γ release levels, 369 MTB proteins stimulated detectable IFN- γ release levels in at least one of the 8 PBMC samples (see table 4 and fig. 4 a). The results were then compared to the final diagnosis obtained for each patient from whom PBMCs were obtained, and further analysis of 97 proteins that only caused IFN-gamma release from non-tubercular patients (see table 4) was excluded. To increase the likelihood of selecting the most promising antigen candidates for further evaluation, 188 MTB proteins (see table 4) that caused IFN- γ release in at least two active tuberculosis patients were selected for further analysis against another 20 PBMC samples from suspected patients. 49 of the 188 candidate antigens from screen 1 with tuberculosis showed strong antigen activity in screen 2 (IFN-. Gamma.release was stimulated in. Gtoreq.40% of the PBMC samples) and were continued for further analysis (see Table 5 and FIG. 4B). 49 antigen candidates caused more than 40% (i.e. more than 8) of IFN-gamma release from the PBMC sample.
The statistical information provided by the blood samples is shown in table 2.
TABLE 2
TABLE 3 Table 3
TABLE 4 Table 4
TABLE 5
The final round of IFN-gamma release screening was performed on the 49 candidate MTB antigens from screen 2, on 20 PBMC samples from active tuberculosis patients and 20 PBMC samples from healthy donors to select for sustained challenge of active tuberculosis (40%) and limited IFN-gamma immune response (30%) in healthy donors. 20 candidate antigens (see Table 6) were evaluated in a mouse challenge model, including 6 PPE protein family members (PPE 22, PPE23, PPE26, PPE28, PPE30, PPE 32), 5 intermediate metabolism and respiratory protein family members (HemZ, rv0082, adhA, nadA, rv 0187), 4 conserved hypothetical proteins (Rv 1352, rv1341, rv1482 and Rv 1147), regulatory protein class (Rv 3095, rv1151 c) 2, lipodystrophin class (Rv 1867, fadD 11.1) 2 and 1 member of the toxic, detoxification and adaptation protein class (Rv 2303 c).
TABLE 6
3. Mycobacterium tuberculosis antigen immunization
BALB/c female mice of 6-8 weeks old purchased from Beijing Vitolihua Biotechnology Co., ltd, were not available at the Beijing thoracic Hospital animal center affiliated to the university of capital medical scienceAnd (3) feeding under special pathogen conditions. In total, 20 MTB antigens were evaluated in 3 experiments, 6 proteins in the first experiment, and 7 proteins in the two subsequent experiments, each including positive and negative controls. After one week of adaptation, mice were randomly divided into experimental and control groups (4 each), immunized 3 times subcutaneously (2 weeks apart), and immunized with 30 μg of Mycobacterium tuberculosis protein in 200 μl of incomplete Freund's adjuvant. Negative control mice were subcutaneously injected with saline and adjuvant 3 times (2 weeks apart), and BCG positive control mice were subcutaneously injected with single dose of BCG 1×10 5 CFU. Mice were monitored daily by the animal care provider until the experiment was terminated.
4. Mycobacterium tuberculosis H37Rv infection
After 6 weeks from the last immunization in step 3, a bacterial suspension of Mycobacterium tuberculosis H37Rv (concentration 5X 10 6 CFU/mL) was injected into the external vein of the tail of the mice (100. Mu.L of each mouse was inoculated at a dose of 5X 10 per mouse 5 CFU), the immunized mice were subjected to mycobacterium tuberculosis H37Rv vein infection. Mice were sacrificed after 6 weeks with cervical dislocation and lungs harvested. The lung organs were transferred to plastic Tekmar bags with 10mL of PBS buffer containing 0.1% (v/v) Tween-80. In FASTPRE-24 (MP biomedical), one leaf of each lung was homogenized in sterile 0.05% pbs-tween 80. Homogenized lung suspensions were plated in 10-fold serial dilutions on MedieBurk7H10 medium. Culturing at 37 deg.C for 3-4 weeks, humidifying air and 5% CO 2 After that, colony Forming Units (CFU) scores. The other lung lobes were fixed in formaldehyde solution (4%) prior to hematoxylin-eosin (HE) and acid fast staining (AF) staining. Pathologists of histology slide exams and blindness scores are not associated with the study.
The inventors of the present invention evaluated the protective efficacy of the 20 candidate MTB antigens selected above in a BALB/c mouse challenge model. 7-9 week old BALB/c mice (three injections at 2 week intervals) were immunized with 30 μg of candidate antigen (in Freund's incomplete adjuvant) via lateral tail vein. After 6 weeks, mycobacterium tuberculosis H37Rv (5X 10 per mouse) 5 CFU) the mice were challenged intravenously and euthanized after six additional weeks. Will be used for waitingComparison of the bacterial load in the lungs of mice vaccinated with selected T cell antigens with those of control mice injected with saline or BCG (see fig. 5a and table 7) shows that the three protein antigens have significant protective efficacy; the pulmonary bacterial load of mice vaccinated with Rv1485 (4.86.+ -. 0.06log10 CFU) was significantly lower than that of the normal saline injected negative control mice (5.33.+ -. 0.04log10CFU, p<0.01, t-test) and can provide a slightly stronger protection than BCG control (5.00±0.04log10 cfu). Similarly, the lung bacterial load of Rv1705c and Rv1802 vaccinated mice was significantly lower than that of the negative control mice (Rv 1705c, 4.72.+ -. 0.07log10CFU versus saline, 5.33.+ -. 0.11log10CFU; rv1802, 4.90.+ -. 0.05log10CFU versus saline, 5.30.+ -. 0.07log10 CFUs). Rv1705c and Rv1485 provide substantially similar protection as BCG (see a and table 7 in fig. 5). Less tissue damage was observed during the lung microscopy of mice immunized with Rv1705c or Rv1485 relative to saline controls, and the lungs of mice immunized with these antigens were similar in appearance to those of mice immunized with BCG (see B in fig. 5). Consistent with this change in bacterial load, a significant difference in Hematoxylin and Eosin (HE) staining of the tissue was observed; similar to BCG controls, mice of Rv1705c or Rv1485 showed more severe interstitial pneumonia and inflammation throughout the lung than in saline controls. Infiltration of inflammatory cells into the alveolar wall was less pronounced and alveolar air gaps were not eliminated to the same extent as saline control (see C in fig. 5). The results of the acid quick staining showed that BCG, rv1705c and Rv1485 inoculated mice had no apparent mycobacterium tuberculosis bacterial cells in lung tissue compared to saline control.
By further assessing 20 of the 49 proteins that induced a strong specific cellular antigen response in the BALB/c mouse challenge model, it was shown that the Rv1705c protein and Rv1485 protein had approximately equivalent protective effects to bcg and significantly reduced bacterial burden in the lungs of infected mice.
TABLE 7
5. Mouse spleen cell culture and cytokine detection
(1) Spleen cells were isolated from mice 3 weeks after the last immunization of step 3. The spleen from harvest was homogenized and filtered through a nylon cell filter (BD Pharmingen company product, pore size 100 μm). The obtained spleen cells were washed twice with RPMI1640 medium (Invitrogen corporation product), centrifuged at 1000rpm for 5min, and the cell pellet was resuspended in the medium (RPMI 1640 medium containing 10% (v/v) FBS) and then inoculated into 96-well plates (about 2.5X10) 5 Cells/wells).
(2) To the 96-well plate, an aqueous solution of Mycobacterium tuberculosis protein (concentration: 10. Mu.g/mL), serum-free medium or PPD (concentration: 10. Mu.g/mL) was added, mixed, and then incubated at 37℃for 24 hours (for detecting IL-2) or 72 hours (for detecting IFN-. Alpha., TNF-. Alpha.IL-4, IL-6 or IL-10).
(3) After completion of step (2), the supernatant was collected by centrifugation at 1000rpm for 5min, and the IFN-. Alpha.s, TNFα, IL-2, IL-4, IL-6 and IL-10 concentrations were detected using ELISA kit (bioleged, san Diego).
6. Antigen-specific antibody titre
After 1 week after the last immunization of step 3, specific serum IgG2a and IgG1 isotype antibody responses were detected by ELISA. The method comprises the following specific steps:
(1) A96-well plate was prepared, and 100. Mu.L of a buffer solution containing Mycobacterium tuberculosis protein at a concentration of 1. Mu.g/mL and having a pH of 9.6 and 0.05M was added to each well, and the mixture was coated overnight at 4 ℃.
(2) After completion of step (1), the 96-well plate was first buffered with PBS-T buffer (containing 137mM NaCl, 2.7mM KCl, 10mM Na 2 HPO 4 、2mM KH 2 PO 4 And 0.05% (v/v) Tween-20) for 3 times; then placing in a blocking buffer (PBS-T buffer containing 3% (v/v) BSA) and standing at 37 ℃ for 2h; finally, the mixture is washed 3 times by PBS-T buffer solution, and then the diluted solution of mouse serum is added for standing reaction for 1h at 37 ℃.
Mouse serum dilution: the mouse serum was diluted to 1000-fold with incubation buffer (PBS-T buffer containing 1% (v/v) BSA).
(3) After the step (2) is completed, the 96-well plate is taken and washed with PBS-T buffer solution for 3 times; horseradish peroxide is then added to each wellEnzyme (HRP) -conjugated goat anti-mouse IgG1 and IgG2a antibodies (Bethyl Laboratories, montary, texas) (working concentration: 10000-fold diluted with incubation buffer), standing for 1h at 37 ℃; then washing 3 times with PBS-T buffer, adding TMB (3, 3', 5' -tetramethylbenzidine) aqueous solution, and incubating the 96-well plate at room temperature for 15min; finally add 2N H 2 SO 4 The reaction was terminated, the light emission at 450nm was read using a microplate reader (Tecan, switzerland) and IgG2a was calculated: igG1 endpoint cost performance.
Potential subunit vaccine candidates must be able to induce humoral responses to provide protection against tuberculosis. To assess the humoral response elicited by Rv1705c and Rv1485, BALB/c mice were immunized (three injections at 2 week intervals) with Rv1705c or Rv1485 (in incomplete freund's adjuvant) via lateral tail veins. Titers of Rv1705c or Rv1485 specific IgG, igG1 and IgG2a were measured in serum obtained three weeks after the last immunization with ELISA. High titers of specific IgG, igG1 and IgG2a for Rv1705c or Rv1485 were observed, and no IgG/IgG1/IgG2a was detected in the vaginal control group (see fig. 6 a and table 8). Th1 immune responses have been reported to have an important protective effect on Mycobacterium tuberculosis infection (Refs), while Th2 immune responses are thought to impair host protective immunity. The ratio of IgG2a/IgG1 (IgG 2a is a Th 1-type antibody and IgG1 is a Th 2-type antibody) was plotted to indicate whether Th1 or Th2 profile was induced by Rv1705c or Rv1485. The IgG2a/IgG1 ratio in Rv1705c group was 3.33 and BCG was 1.33, indicating that a moderate Th1 type immune response was induced in response to Rv1705c antigen. The IgG2a/IgG1 ratio in the Rv1485 group was 1.67 and BCG was 1.33, indicating that a moderate Th1 type immune response was induced in response to the Rv1485 antigen.
TABLE 8
Since mycobacterium tuberculosis is an intracellular pathogen, the importance of the cellular response is at least as important as the humoral response. To evaluate cellular responses, secretion of typical Th1 cytokines IL-2, IL-6, TNF- α and IFN- α were measured, which not only activate macrophages, but also promote polarization of effector Th1 cells and Th2 cytokines, IL-4 and IL-10, which are responsible for inhibiting macrophage function and promoting antibody responses. Mice immunized with Rv1705c or Rv1485 (3 times, 2 weeks apart) were euthanized 4 weeks after the third round of immunization, and spleen cells were harvested. Cytokine expression levels in culture supernatants of isolated spleen cells stimulated with antigen and PPD (purified protein derivative), respectively, were measured by ELISA. The results showed that Th1 cytokines IL-2, IL-6, TNF-. Alpha.and IFN-. Gamma.were all present at high concentrations after stimulation with either Rv1705c or Rv1485, whereas Th2 cytokines IL-4 and IL-10 were not detected (see FIG. 6, B and Table 9). The levels of cytokine detected were significantly higher for Rv1705c or Rv1485 immunized mice than for BCG immunized mice, probably because these mice received only one BCG immunization rather than three immunizations of Rv1705 or Rv1485 immunized mice. In addition, the time between BCG immunization and euthanasia was 8 weeks for BCG immunized mice and 4 weeks for mice immunized with Rv1705c or Rv1485, and no spleen cells harvested were stimulated with any immunogen prior to measuring cytokine release. Th1 cytokines such as IL-2, TNF- α and the well known anti-tuberculosis cytokine IFN- γ promote Th1 immune responses, play an important role in combating pathogens, controlling tuberculosis and effectively protecting the host. The results indicate that Rv1705c or Rv1485 elicit potent Th 1-type humoral and cellular immune responses, favoring tuberculosis control, possibly explaining why Rv1705c protein or Rv1485 protein may protect the host from mycobacterium tuberculosis.
TABLE 9
<110> biological physical institute of sciences of China academy of sciences of biological sciences of Guangdong Libikang
<120> application of mycobacterium tuberculosis antigen protein Rv1485 in preparation of tuberculosis vaccine
<160> 2
<170> PatentIn version 3.5
<210> 1
<211> 385
<212> PRT
<213> Artificial sequence
<400> 1
Met Asp Phe Gly Ala Leu Pro Pro Glu Val Asn Ser Gly Arg Met Tyr
1 5 10 15
Cys Gly Pro Gly Ser Ala Pro Met Val Ala Ala Ala Ser Ala Trp Asn
20 25 30
Gly Leu Ala Ala Glu Leu Ser Val Ala Ala Val Gly Tyr Glu Arg Val
35 40 45
Ile Thr Thr Leu Gln Thr Glu Glu Trp Leu Gly Pro Ala Ser Thr Leu
50 55 60
Met Val Glu Ala Val Ala Pro Tyr Val Ala Trp Met Arg Ala Thr Ala
65 70 75 80
Ile Gln Ala Glu Gln Ala Ala Ser Gln Ala Arg Ala Ala Ala Ala Ala
85 90 95
Tyr Glu Thr Ala Phe Ala Ala Ile Val Pro Pro Pro Leu Ile Ala Ala
100 105 110
Asn Arg Ala Arg Leu Thr Ser Leu Val Thr His Asn Val Phe Gly Gln
115 120 125
Asn Thr Ala Ser Ile Ala Ala Thr Glu Ala Gln Tyr Ala Glu Met Trp
130 135 140
Ala Gln Asp Ala Met Ala Met Tyr Gly Tyr Ala Gly Ser Ser Ala Thr
145 150 155 160
Ala Thr Lys Val Thr Pro Phe Ala Pro Pro Pro Asn Thr Thr Ser Pro
165 170 175
Ser Ala Ala Ala Thr Gln Leu Ser Ala Val Ala Lys Ala Ala Gly Thr
180 185 190
Ser Ala Gly Ala Ala Gln Ser Ala Ile Ala Glu Leu Ile Ala His Leu
195 200 205
Pro Asn Thr Leu Leu Gly Leu Thr Ser Pro Leu Ser Ser Ala Leu Thr
210 215 220
Ala Ala Ala Thr Pro Gly Trp Leu Glu Trp Phe Ile Asn Trp Tyr Leu
225 230 235 240
Pro Ile Ser Gln Leu Phe Tyr Asn Thr Val Gly Leu Pro Tyr Phe Ala
245 250 255
Ile Gly Ile Gly Asn Ser Leu Ile Thr Ser Trp Arg Ala Leu Gly Trp
260 265 270
Ile Gly Pro Glu Ala Ala Glu Ala Ala Ala Ala Ala Pro Ala Ala Val
275 280 285
Gly Ala Ala Val Gly Gly Thr Gly Pro Val Ser Ala Gly Leu Gly Asn
290 295 300
Ala Ala Thr Ile Gly Lys Leu Ser Leu Pro Pro Asn Trp Ala Gly Ala
305 310 315 320
Ser Pro Ser Leu Ala Pro Thr Val Gly Ser Ala Ser Ala Pro Leu Val
325 330 335
Ser Asp Ile Val Glu Gln Pro Glu Ala Gly Ala Ala Gly Asn Leu Leu
340 345 350
Gly Gly Met Pro Leu Ala Gly Ser Gly Thr Gly Thr Gly Gly Ala Gly
355 360 365
Pro Arg Tyr Gly Phe Arg Val Thr Val Met Ser Arg Pro Pro Phe Ala
370 375 380
Gly
385
<210> 2
<211> 344
<212> PRT
<213> Artificial sequence
<400> 2
Met Gln Phe Asp Ala Val Leu Leu Leu Ser Phe Gly Gly Pro Glu Gly
1 5 10 15
Pro Glu Gln Val Arg Pro Phe Leu Glu Asn Val Thr Arg Gly Arg Gly
20 25 30
Val Pro Ala Glu Arg Leu Asp Ala Val Ala Glu His Tyr Leu His Phe
35 40 45
Gly Gly Val Ser Pro Ile Asn Gly Ile Asn Arg Thr Leu Ile Ala Glu
50 55 60
Leu Glu Ala Gln Gln Glu Leu Pro Val Tyr Phe Gly Asn Arg Asn Trp
65 70 75 80
Glu Pro Tyr Val Glu Asp Ala Val Thr Ala Met Arg Asp Asn Gly Val
85 90 95
Arg Arg Ala Ala Val Phe Ala Thr Ser Ala Trp Ser Gly Tyr Ser Ser
100 105 110
Cys Thr Gln Tyr Val Glu Asp Ile Ala Arg Ala Arg Arg Ala Ala Gly
115 120 125
Arg Asp Ala Pro Glu Leu Val Lys Leu Arg Pro Tyr Phe Asp His Pro
130 135 140
Leu Phe Val Glu Met Phe Ala Asp Ala Ile Thr Ala Ala Ala Ala Thr
145 150 155 160
Val Arg Gly Asp Ala Arg Leu Val Phe Thr Ala His Ser Ile Pro Thr
165 170 175
Ala Ala Asp Arg Arg Cys Gly Pro Asn Leu Tyr Ser Arg Gln Val Ala
180 185 190
Tyr Ala Thr Arg Leu Val Ala Ala Ala Ala Gly Tyr Cys Asp Phe Asp
195 200 205
Leu Ala Trp Gln Ser Arg Ser Gly Pro Pro Gln Val Pro Trp Leu Glu
210 215 220
Pro Asp Val Thr Asp Gln Leu Thr Gly Leu Ala Gly Ala Gly Ile Asn
225 230 235 240
Ala Val Ile Val Cys Pro Ile Gly Phe Val Ala Asp His Ile Glu Val
245 250 255
Val Trp Asp Leu Asp His Glu Leu Arg Leu Gln Ala Glu Ala Ala Gly
260 265 270
Ile Ala Tyr Ala Arg Ala Ser Thr Pro Asn Ala Asp Pro Arg Phe Ala
275 280 285
Arg Leu Ala Arg Gly Leu Ile Asp Glu Leu Arg Tyr Gly Arg Ile Pro
290 295 300
Ala Arg Val Ser Gly Pro Asp Pro Val Pro Gly Cys Leu Ser Ser Ile
305 310 315 320
Asn Gly Gln Pro Cys Arg Pro Pro His Cys Val Ala Ser Val Ser Pro
325 330 335
Ala Arg Pro Ser Ala Gly Ser Pro
340