Application of bifidobacterium longum subsp. Infantis in prevention and / or treatment of allergic rhinitis

Abstract

The invention relates to the technical field of biological medicines, in particular to application of bifidobacterium longum subsp. Infantis in prevention and / or treatment of allergic rhinitis. Researches find that the Bifidobacterium longum subsp.infantis can improve inflammatory response, relieve symptoms of allergic rhinitis of mice, inhibit immune response caused by the allergic rhinitis, inhibit the inflammatory response caused by the allergic rhinitis and / or repair nasal mucosa injury caused by the allergic rhinitis, and the Bifidobacterium longum subsp.infantis can be used for treating the allergic rhinitis. The compound has a huge application prospect in preparation of products for preventing and / or treating allergic rhinitis.

Description

Technical Field

[0001] The present invention relates to the field of biomedicine technology, and in particular to application of Bifidobacterium longum subspecies infantis in preventing and / or treating allergic rhinitis. Background Art

[0002] Hypersensitive rhinitis is a non-infectious inflammatory disease of the nasal mucosa, a type of allergy. Its symptoms are similar to those of a cold. The primary symptom is sneezing, followed by itchy eyes, itchy nose, nasal congestion, runny nose, and clear, white discharge (a runny nose). These symptoms recur intermittently. During an attack, the nasal mucosa becomes pale and swollen, and those with allergies may experience hives. Severe cases may also develop into sinusitis, asthma, or ear infections.

[0003] There's no complete cure for allergic rhinitis, but symptoms are generally alleviated through medication or other methods. For example, antihistamines such as cetirizine hydrochloride and loratadine are often prescribed when the condition strikes. Corticosteroids and other steroids can also reduce the frequency of allergic rhinitis attacks or alleviate the allergic reaction. Decongestants can reduce congestion and edema in the nasal mucosa, improving the nasal congestion symptoms of allergic rhinitis. However, traditional antihistamines can cause side effects such as drowsiness, fatigue, headaches, and constipation. Corticosteroids can also cause endocrine disorders, decreased immunity, and osteoporosis. Decongestants can also lead to elevated blood pressure, angina attacks, arrhythmias, migraines, and ischemic strokes. Therefore, the search for allergic rhinitis treatments with fewer side effects, greater effectiveness, and less risk of developing immune tolerance is urgent. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies of the prior art and provide a use of Bifidobacterium longum subsp. infantis in the preparation of a product for preventing and / or treating allergic rhinitis.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides a use of Bifidobacterium longum subsp. infantis in the preparation of a product for preventing and / or treating allergic rhinitis, wherein the Bifidobacterium longum subsp. infantis is strain XA-9111, with a deposit number of CGMCC No. 26615.

[0007] The present invention has found through research that Bifidobacterium longum subsp. infantis can alleviate the symptoms of allergic rhinitis in mice, reduce the IgE content in the serum of mice with allergic rhinitis, reduce the histamine content in the serum of mice with allergic rhinitis, reduce the content of pro-allergenic cytokines in the serum of mice with allergic rhinitis, improve the Th1 type immune response activity in mice with allergic rhinitis, reduce the level of pro-inflammatory cytokines in the serum of mice with allergic rhinitis, and repair damaged nasal mucosa in mice with allergic rhinitis. Therefore, the present invention has great application prospects in the preparation of products for preventing and / or treating allergic rhinitis.

[0008] Preferably, the prevention and / or treatment of allergic rhinitis includes alleviating the symptoms of allergic rhinitis, inhibiting the immune response caused by allergic rhinitis, inhibiting the inflammatory response caused by allergic rhinitis and / or repairing nasal mucosal damage caused by allergic rhinitis.

[0009] Preferably, the allergic rhinitis symptom relief comprises reducing the frequency of allergic reactions in patients with allergic rhinitis.

[0010] Preferably, the allergic rhinitis causes elevated levels of IgE and cytokines in serum.

[0011] Preferably, the cytokines include IL-4, IL-5, IL-13, IL-6, and IFN-γ.

[0012] Preferably, the products include food, health products, and medicines.

[0013] Preferably, the number of viable bacteria of Bifidobacterium longum subsp. infantis in the product is not less than 1×10 6 CFU / mL or 1×10 6 CFU / g.

[0014] Preferably, the dosage form of the product includes liquid and solid; when the dosage form of the product is liquid, the number of viable bacteria in the product is not less than 1×10 6 CFU / mL; when the dosage form of the product is solid, the number of viable bacteria in the product is not less than 1×10 6 CFU / g.

[0015] In a second aspect, the present invention provides a use of Bifidobacterium longum subsp. infantis in the preparation of a product for improving inflammatory response, wherein the Bifidobacterium longum subsp. infantis is strain XA-9111, with a deposit number of CGMCC No. 26615.

[0016] The present invention also found that Bifidobacterium longum subsp. infantis can reduce histamine release induced by anti-DNP-IgE, reduce the degree of RBL-2H3 cell degranulation induced by anti-DNP-IgE, and inhibit the release of inflammatory cytokines induced by LPS, thereby being used to improve inflammatory responses.

[0017] Preferably, the inflammatory response is caused by histamine.

[0018] Preferably, the Bifidobacterium longum subsp. infantis improves inflammatory response by reducing histamine levels.

[0019] Preferably, the inflammatory response comprises pruritus.

[0020] Preferably, the products include food, health products, and medicines.

[0021] Preferably, the number of viable bacteria of Bifidobacterium longum subsp. infantis in the product is not less than 1×10 6 CFU / mL or 1×10 6 CFU / g.

[0022] Preferably, the dosage form of the product includes liquid and solid; when the dosage form of the product is liquid, the number of viable bacteria in the product is not less than 1×10 6 CFU / mL; when the dosage form of the product is solid, the number of viable bacteria in the product is not less than 1×10 6 CFU / g.

[0023] Preferably, when the product is a drug, it also contains a drug carrier and / or a pharmaceutical excipient.

[0024] Preferably, the drug carrier comprises at least one of microcapsules, microspheres, nanoparticles, and liposomes.

[0025] Preferably, the pharmaceutical excipients include excipients and / or additives.

[0026] Preferably, the excipient comprises at least one of a solvent, a propellant, a solubilizer, a cosolvent, an emulsifier, a colorant, an absorbent, a diluent, a flocculant, a deflocculant, a filter aid, and a release retardant.

[0027] Preferably, the additive includes at least one of microcrystalline cellulose, hydroxypropyl methylcellulose, and refined lecithin.

[0028] Preferably, the dosage form of the drug is powder, granule, capsule, tablet, pill or oral solution.

[0029] Preferably, when the product is a medicine, it also contains food additives.

[0030] Preferably, the food additives include at least one of antioxidants, bleaching agents, colorants, color preservatives, enzyme preparations, flavor enhancers, preservatives, and sweeteners.

[0031] The beneficial effects of the present invention are:

[0032] Bifidobacterium longum subsp. infantis is a probiotic currently included in the national list of edible probiotics. Bifidobacterium longum subsp. infantis XA-9111, and products containing this strain as an active ingredient, offer advantages such as minimal side effects, a low barrier to entry for patients, a low likelihood of developing immune tolerance, and low manufacturing costs. These advantages suggest significant development potential and promising market prospects.

[0033] The present invention provides the use of Bifidobacterium longum subsp. infantis in preventing or treating allergic rhinitis. The present invention finds that Bifidobacterium longum subsp. infantis has the following effects:

[0034] (1) It can significantly alleviate the symptoms of allergic rhinitis in mice (i.e., reduce the number of times mice with allergic rhinitis scratch their noses, sneeze, and have runny noses), and can significantly repair the damaged nasal mucosa of mice with allergic rhinitis.

[0035] (2) It can significantly reduce the levels of IgE, histamine, and pro-inflammatory cytokines (IL-4, IL-5, and IL-13) in the serum of mice with allergic rhinitis; it can significantly increase the Th1 immune response activity in the body of mice with allergic rhinitis (i.e., increase the ratio of IFN-γ / IL-4 in the serum of mice with allergic rhinitis); it can significantly reduce the levels of pro-inflammatory cytokines (IL-6 and THF-α) in the serum of mice with allergic rhinitis;

[0036] (3) It can significantly reduce the histamine concentration and cell degranulation degree of RBL-2H3 cells induced by anti-DNP-IgE; it can also significantly inhibit the release of inflammatory cytokines (IFN-γ, IL-10, IL-4, IL-6 and THF-α) induced by LPS.

[0037] Therefore, the strain has great application prospects in the preparation of products (such as food, health products or medicines, etc.) for preventing and / or treating allergic rhinitis. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on the DAI score of mice with OVA-induced allergic rhinitis.

[0039] Figure 2 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on serum IgE levels in mice with OVA-induced allergic rhinitis.

[0040] Figure 3 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on the serum IL-4 concentration in mice with OVA-induced allergic rhinitis.

[0041] Figure 4 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on the serum IL-5 concentration in mice with OVA-induced allergic rhinitis.

[0042] Figure 5 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on the serum IL-13 concentration in mice with OVA-induced allergic rhinitis.

[0043] Figure 6 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on the serum IFN-γ / IL-4 ratio in mice with OVA-induced allergic rhinitis.

[0044] Figure 7 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on the serum IL-6 concentration in mice with OVA-induced allergic rhinitis.

[0045] Figure 8 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on nasal mucosal pathology in mice with OVA-induced allergic rhinitis.

[0046] Figure 9 This figure shows the effect of Bifidobacterium longum subsp. infantis XA-9111 on histamine production in RBL-2H3 cells induced by anti-DNP-IgE.

[0047] Figure 1-9 In the table, * represents p < 0.05, ** represents p < 0.01, *** represents p < 0.001, and **** represents p < 0.0001. DETAILED DESCRIPTION

[0048] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0049] Unless otherwise specified, the reagents and materials used in the present invention are conventional commercially available products.

[0050] The culture medium formula used in the present invention is as follows:

[0051] MRS solid medium: peptone 10 g / L, beef extract powder 5 g / L, yeast extract powder 4 g / L, glucose 20 g / L, sodium acetate 5 g / L, dipotassium hydrogen phosphate 2 g / L, ammonium citrate 2 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.05 g / L, Tween 80 1 g / L, agar 15 g / L, cysteine salt 0.5 g / L, pH 6.8.

[0052] MRS liquid medium: peptone 10 g / L, beef extract powder 5 g / L, yeast extract powder 4 g / L, glucose 20 g / L, sodium acetate 5 g / L, dipotassium hydrogen phosphate 2 g / L, ammonium citrate 2 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.05 g / L, Tween 80 1 g / L, cysteine salt 0.5 g / L, pH 6.8.

[0053] The Bifidobacterium longum subsp. infantis strain used in the present invention is strain XA-9111, which is deposited in the General Microbiology Center of the China Culture Collection Administration of Microorganisms with a deposit number of CGMCC No. 26615 and a deposit address of No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing (this strain has been disclosed in Patent No. CN117887613 A).

[0054] Preparation of XA-9111 bacterial suspension:

[0055] The method comprises the following steps: streak Bifidobacterium longum subsp. infantis XA-9111 on MRS solid medium and cultured at 37°C for 48 hours to obtain a single colony; picking a single colony and inoculating it into MRS liquid medium and incubating it at 37°C for 18 hours for activation to obtain an activation solution; inoculating the activation solution into MRS liquid medium at an inoculum volume of 4% (v / v), and incubating it at 37°C for 18 hours to obtain a bacterial solution; centrifuging the bacterial solution at 3000 g for 10 minutes to obtain Bifidobacterium longum subsp. infantis cells; washing the Bifidobacterium longum subsp. infantis cells with 0.9% (m / v, g / 100 mL) physiological saline and resuspending them in 0.9% (m / v, g / 100 mL) physiological saline to a bacterial concentration of 1×10 10 CFU / mL, and obtain XA-9111 bacterial suspension.

[0056] Experimental Example 1: Strain Isolation and Identification

[0057] 1. Isolation and screening of strains

[0058] Fresh feces from healthy people in Shenzhen were used as samples. 0.5 g of fresh feces sample was added to 5 mL of MRS liquid medium and cultured at 37 °C for 24 h to obtain the enriched sample. 0.5 mL of the enriched sample was added to 4.5 mL of sterile saline to obtain 10 -1 diluent, then draw 0.5mL 10 -1 Dilute in 4.5 mL of saline to obtain 10 -2 Dilution, operate in sequence, get 10 -3 , 10 -4 , 10 -5 , 10 -6 Dilution: 100 μL gradient dilution was applied to MRS solid medium, 10 -4 , 10 -5 , 10 -6 One plate was used for each gradient and cultured at 37°C for 48 hours to obtain colonies; colonies with typical characteristics of Bifidobacterium longum on MRS solid culture medium were selected according to the shape, size, edge, transparency, etc. of the colonies, and the colonies were picked with an inoculation loop and streaked on the MRS solid culture medium, and cultured at 37°C for 48 hours to obtain purified single colonies; the purified single colonies were picked and inoculated into 5 mL of MRS liquid culture medium respectively, and cultured at 37°C for 24 hours to obtain bacterial liquid; after numbering each strain corresponding to each bacterial liquid, Gram staining, strain identification, physiological and biochemical experiments and genomic identification analysis were performed according to the steps recorded in the textbook "Microbiology" (edited by Shen Ping and Chen Xiangdong), and hemolytic activity test was performed according to the steps recorded in 3.7 of the "Technical Guidelines for Safety Inspection and Evaluation of Bacteria for Health Food Raw Materials" (2020 edition), and a strain with typical characteristics of Bifidobacterium longum infantis subspecies was selected and named strain XA-9111.

[0059] 2. Gram staining identification of strains

[0060] The Gram staining process is as follows:

[0061] Single colonies of strain XA-9111 were selected for bacterial smears, dried, and then heat-fixed; crystal violet was added for staining for 10 seconds, washed with water, and then dried; iodine solution was added for staining for 10 seconds, washed with water, and then dried; decolorization was added for 10 seconds, washed with water, and then dried; safranin solution was added for counterstaining for 10 seconds, and washed with water; after the specimen slides were naturally dried, 1 drop of cedar oil was added to the smeared area for observation under an oil microscope.

[0062] The results showed that the strain was purple in color after Gram staining and was a rod-shaped Gram-positive bacterium.

[0063] 3. Strain identification

[0064] The process is as follows:

[0065] The bacterial cells screened in step (1) were used to extract the genome of XA-9111 using a bacterial genome extraction kit. The primer pair used was 27F / 1492R, and its sequence is shown below (in 27F and 1492R, M and Y are degenerate bases, M = A or C, Y = Cor T):

[0066] 27F:AGAGTTTGATCMTGGCTCA;

[0067] 1492R:TGTACGGYTACCTTGTTACGACTT.

[0068] The extracted genome of XA-9111 was used as a template for amplification to obtain the 16S rRNA of XA-9111; the 16S rDNA of XA-9111 was aligned with the nucleic acid sequence using the Blastn program of NCBI.

[0069] After identification, the strain was found to be Bifidobacterium longum subsp. infantis, named XA-9111. The strain was deposited in the General Microbiology Center of the China Culture Collection Administration, with the deposit number CGMCC No. 26615, and the deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0070] 4. Physiological and biochemical experiments

[0071] A single colony of XA-9111 was picked up with a sterile cotton swab and inoculated into sterile saline. A homogenous bacterial suspension was prepared using DensiCHEK™ Plus at a McFarland turbidity of 3.0. Within 30 minutes of preparation, the suspension was loaded onto an API20A instrument for physiological and biochemical analysis. The results showed that XA-9111 could utilize D-glucose, D-sucrose, D-mannose, D-trehalose, D-maltose, and D-arabinose as carbon sources.

[0072] 5. Genome identification and analysis

[0073] Take XA-9111 bacteria, extract DNA from bacteria by SDS method, and detect the quality of extracted DNA by agarose electrophoresis. DNA quantification was performed using PCR-based sequencing technology (PCR) 2.0. The genome was sequenced using the Nanopore PromethION platform and the Illumina NovaSeq platform, using a 10 kb library and a sequencing depth of ≥100×. Sequencing results showed that strain XA-9111 contained a circular genome of 2.97 Mbp and three circular plasmids of 12.88 kbp, 49.33 kbp, and 78.09 kbp, respectively. Comparison of the amino acid sequence encoded by the genome of strain XA-9111 with the VFDB database revealed that the sequences of potential virulence factors all showed less than 80% identity, and most had no clear function. Comparison of the amino acid sequence encoded by the genome of strain XA-9111 with the ARDB database for analysis of potential drug resistance genes revealed that the sequences of these genes all showed less than 55% identity. These results indicate that strain XA-9111 has a high safety profile.

[0074] Experimental Example 2: Effects of Bifidobacterium longum subsp. infantis XA-9111 on a mouse model of allergic rhinitis

[0075] Experimental process:

[0076] 1. Construction of mouse model

[0077] Twenty-seven SPF-grade BABL / C female mice aged 6 to 8 weeks (purchased from Beijing Weitonglihua Biotechnology Co., Ltd., weighing 18±2g) were randomly divided into three groups, with 9 mice in each group. The three groups were: control group (CON), model control group (AR), and probiotic intervention group (XA-9111) that was gavaged with XA-9111 bacterial suspension.

[0078] Mice in the model group and probiotic intervention group were sensitized by intraperitoneal injection of 200 μL OVA suspension (OVA concentration of 1 mg / mL, solvent: normal saline) on days 0, 7, and 14 of the experiment. Mice in the probiotic intervention group were gavaged daily with 200 μL of bacteria (1×10 10 The control group and the model control group were gavaged with an equal amount of 0.9% saline solution.

[0079] Starting from the 21st day of the experiment, the model group and the probiotic intervention group were given 500 μg of OVA in the nose every day to create an allergic rhinitis mouse model. Starting from the 28th day of the experiment, the symptoms of allergic rhinitis (number of nose scratching, number of sneezing, number of runny nose) of all groups of mice within ten minutes after the nose drops were recorded. The 29th day was the end point of the experiment. After euthanasia, all mice were evaluated for inflammation according to the evaluation criteria. Among them, the main indicators for evaluating allergic rhinitis were DAI score, IgE content in mouse serum, cytokine content in mouse serum, and histopathological section evaluation.

[0080] 2. Inflammation evaluation

[0081] (1) DAI score

[0082] The DAI score includes the number of nose scratching, sneezing, and runny nose. For details, see "Zhu Y, Yu J, et al. Experimental observation of the effect of immunotherapy on CD4+ T cells and Th1 / Th2 cytokines in mice with allergic rhinitis, Scientific Reports, 2023, 13:5273." The DAI score is an important indicator for evaluating rhinitis symptoms in mice. This score is composed of the number of nose scratching, sneezing, and runny nose. A higher score indicates more severe allergic rhinitis symptoms in mice.

[0083] At the end of the experiment, the DAI scores of mice in all groups were as follows: Figure 1 As shown. Compared with the control group (approximately 0.2 points), the DAI scores of mice in the model group were significantly increased (increased to approximately 2 points). However, after the mice were treated with strain XA-9111, their DAI scores were significantly decreased compared with the model group (decreased to approximately 1 point). These results indicate that XA-9111 can alleviate the increase in DAI scores caused by OVA and significantly reduce OVA-induced behaviors in mice, such as itching, scratching, sneezing, and runny nose.

[0084] (2) After euthanasia at the end of the experiment, the blood of mice in all groups was collected and the serum was separated. The mouse immunoglobulin E (IgE) ELISA kit (catalog number ml037602, purchased from Shanghai ELISA), histamine ELISA kit (catalog number ZK-15029, purchased from Shanghai Zhenke Biotechnology), and LEGENDplex MU Th1 / Th2 panel (8-plex) cytokine detection kit (catalog number 741053, purchased from Shenzhen Dakowei) were used to detect the levels of IgE, histamine and cytokines in the serum.

[0085] The immune system overreacts to allergens by producing immunoglobulin E (IgE). Most patients with allergic rhinitis show elevated IgE levels in their blood. Studies have shown that OVA-induced allergic rhinitis can cause elevated IgE levels in mouse serum. In this experiment, the IgE level test results were as follows: Figure 2As shown, compared with the control group, the IgE content in the serum of the model group mice increased significantly after OVA sensitization (increased by about 33 times), and the IgE content in the serum of the mice treated with XA-9111 showed a downward trend (decreased by about 90%), demonstrating the potential of XA-9111 in treating allergic rhinitis.

[0086] IL-4, IL-5, and IL-13 in the interleukin (IL) family have been shown to be positively correlated with the severity of allergic rhinitis as sensitizing factors. Figure 4-5 As shown, after OVA stimulation, the levels of IL-4, IL-5, and IL-13 in the serum of mice all showed an upward trend (increases of approximately 200%, 100%, and 220%, respectively). After XA-9111 treatment, cytokine levels approached those of the control group and decreased compared to the model group (decreases of approximately 50%, 37%, and 89%, respectively). This demonstrates that XA-9111 can alleviate the symptoms of allergic rhinitis by regulating serum cytokine levels.

[0087] IFN-γ is an important cytokine for Th1 cells and has an antagonistic effect on IL-4. Therefore, the activity status of Th1 cells and Th2 cells can be reflected by evaluating the concentration ratio of IFN-γ to IL-4. Figure 6 As shown in the data, compared with the control group, the ratio of IFN-γ / IL-4 in the serum of mice in the model group showed a downward trend (decreased by about 33%), while after treatment with XA-9111, the ratio rebounded (increased by about 48%). The above results indicate that after treatment with Bifidobacterium longum subsp. infantis XA-9111, the Th1 immune response activity of mice was enhanced, which inhibited the Th2 immune response that mediates allergic reactions to a certain extent and alleviated allergic symptoms.

[0088] IL-6, as a pro-inflammatory factor, has been shown to be positively correlated with inflammation in vivo. Figure 7 As shown, IL-6 levels in mouse serum increased significantly after OVA stimulation (by approximately 170%). After treatment with strain XA-9111, IL-6 levels decreased (by approximately 48%), indicating that XA-9111 can inhibit inflammation in mice and has a positive effect on the treatment of allergic rhinitis.

[0089] (3) At the end of the experiment, the mice were euthanized and the nasal mucosa was removed and fixed with 4% (m / v, g / 100 mL) paraformaldehyde. After fixation, paraffin sections were prepared and H&E and PAS staining experiments were performed to evaluate the pathological results of the nasal mucosa.

[0090] Pathological sections of the nasal mucosa of mice with allergic rhinitis showed ciliary loss, vascular congestion, vascular proliferation, thickening of the nasal mucosa, and infiltration of inflammatory cells compared to normal mice. Figure 8As shown, the control group mice showed normal nasal mucosal surfaces, with intact and neat structures and no mucosal swelling. However, the model group had significantly thickened mucosal layers and irregularly arranged mucosal surfaces. Mice treated with strain XA-9111 showed significant recovery, with intact and neatly arranged epithelial structures and mucosal thickness restored to levels similar to those of the control group.

[0091] Experimental Example 3: Effect of Bifidobacterium longum subsp. infantis XA-9111 on histamine secretion in RBL-2H3 cells induced by anti-DNP-IgE

[0092] Experimental process:

[0093] RBL-2H3 cells (purchased from the Cell Resource Center of the Institute of Basic Medicine, Chinese Academy of Medical Sciences) were taken out of the liquid nitrogen tank and thawed in a 37°C water bath with shaking for 3 minutes to obtain thawed RBL-2H3 cells. The RBL-2H3 cells were first washed with PBS buffer preheated at 37°C, and then 8 mL of cell culture medium (MEM medium containing 10% fetal bovine serum, % refers to volume ratio, MEM medium purchased from Gibco, and fetal bovine serum purchased from Solebol) was added and cultured at 5% (v / v) CO2 and 37°C for 48 hours until the logarithmic growth phase. The density of the RBL-2H3 cells in the logarithmic growth phase was adjusted to 5×10 5 After inoculation into 24-well plates, 400 μL per well, i.e. 2×10 5 Pieces / hole.

[0094] Control wells (CON) were set up without any stimulant, and 0.2 μg / mL anti-DNP-IgE (purchased from Sigma) was added to other wells and stimulated at 5% (v / v) CO2 and 37°C for 16 hours. After the stimulation, the cells were washed three times with PBS buffer and replaced with new MEM medium (purchased from Gibco). Treatment wells (IgE) without strain interaction and treatment wells with strain XA-9111 interaction were set up. After the strain was added, the cells were interacted at 5% (v / v) CO2 and 37°C for 3 hours. After the interaction, 1 μg / mL DNP-HAS (purchased from 4ADI) was added to each well and stimulated at 5% (v / v) CO2 and 37°C for 15 minutes. After the stimulation, 100 μL of cell culture supernatant was aspirated, and 20 μL of 1 M NaOH solution and 25 μL of reaction solution were added. The reaction solution was methanol (purchased from Sangon Biotech (Shanghai) Co., Ltd.) containing 1% (w / v, g / 100 mL) o-phthalaldehyde (purchased from Sigma). The cells were incubated at room temperature (25°C) in the dark for 4 min. After the incubation, 10 μL of 3 M HCl solution was added to terminate the reaction. After termination of the reaction, the fluorescence intensity was detected using a multifunctional microplate reader (excitation wavelength: 355 nm, emission wavelength: 460 nm), and the histamine level in each well was calculated using formula (1).

[0095] Histamine level = OD460 x / OD460 CON，avrg—— Formula (1)

[0096] In the above formula, OD460 x OD460 is the fluorescence intensity of the sample at 460 nm. CON，avrg is the average fluorescence intensity of the CON group at 460 nm.

[0097] Experimental results:

[0098] As the center of itch mediator, histamine content is proportional to the severity of allergic symptoms. Figure 9 As shown, the level of histamine secreted by RBL-2H3 cells in the treatment group was higher than that in the control group (increased by about 63%), while after treatment with Bifidobacterium longum subsp. infantis XA-9111, a decrease in histamine was observed (about 60%). This shows that Bifidobacterium longum subsp. infantis XA-9111 can reduce the concentration of histamine released by RBL-2H3 cells induced by anti-DNP-IgE.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. Use of Bifidobacterium longum subsp. infantis in the preparation of a product for preventing and / or treating allergic rhinitis, characterized in that: The Bifidobacterium longum subspecies infantis is strain XA-9111, and its preservation number is CGMCC No.26615.

2. The use according to claim 1, characterized in that The prevention and / or treatment of allergic rhinitis includes relieving the symptoms of allergic rhinitis, inhibiting the immune response caused by allergic rhinitis, inhibiting the inflammatory response caused by allergic rhinitis and / or repairing the nasal mucosal damage caused by allergic rhinitis.

3. The use according to claim 2, characterized in that The relief of the symptoms of allergic rhinitis includes reducing the frequency of allergic reactions in patients with allergic rhinitis.

4. The use according to claim 1, wherein Allergic rhinitis can cause elevated levels of IgE and cytokines in serum.

5. The use according to claim 4, characterized in that The cytokines include IL-4, IL-5, IL-13, IL-6, and IFN-γ.

6. Use of Bifidobacterium longum subsp. infantis in the preparation of a product for improving inflammatory response, characterized in that: The Bifidobacterium longum subspecies infantis is strain XA-9111, and its preservation number is CGMCC No.26615.

7. The use according to claim 6, characterized in that The inflammatory response is caused by histamine.

8. The use according to claim 6, characterized in that The Bifidobacterium longum subsp. infantis improves inflammatory response by reducing histamine levels.

9. The use according to claim 6, characterized in that The inflammatory response includes itching.

10. The use according to claim 1 or 6, characterized in that The products include food, health products, and medicines.

11. The use according to claim 1 or 6, characterized in that The number of viable bacteria of Bifidobacterium longum subsp. infantis in the product is not less than 1×10 6 CFU / mL or 1×10 6 CFU / g.

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