Antigen-nonspecific IgA secretion enhancer, and composition for enhancing antigen-nonspecific IgA secretion

Abstract

To provide an antigen-non-specific IgA secretion enhancer, and an antigen-non-specific IgA secretion enhancing composition that includes the antigen-non-specific IgA secretion enhancer.SOLUTION: An antigen-non-specific IgA secretion enhancer includes polyglutamic acid or a salt thereof as an active ingredient. There is also provided an antigen-non-specific IgA secretion enhancing composition that includes the antigen-non-specific IgA secretion enhancer, or a composition for inhibiting a decline in immune function associated with aging.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an antigen-nonspecific IgA secretion enhancer and a composition for enhancing antigen-nonspecific IgA secretion.

Background Art

[0002] It is known that the immune function is impaired by aging and stress. Currently, plasma lactic acid bacteria are known as food materials with functional indications related to the immune function. The sales of beverages, confectioneries, etc. added with plasma lactic acid bacteria are expanding, and the need for functional foods appealing to the immune function is high.

[0003] Immunoglobulin A (IgA) constantly secreted on the mucosal surface functions as a barrier on the mucosal surface, prevents the invasion of foreign substances such as bacteria and viruses, and is important for infection prevention. Secretory IgA is roughly classified into antigen-specific secretory IgA produced by the T cell-dependent pathway (T cell-dependent secretory IgA: TD-SIgA) and antigen-specific secretory IgA produced by the T cell-independent pathway (T cell-independent secretory IgA: TI-SIgA). TD-SIgA is controlled by acquired immunity and produced in response to an antigen. On the other hand, TI-SIgA is controlled by innate immunity and constantly produced regardless of the presence or absence of an antigen. TI-SIgA is considered to contribute to the initial immunity and the constancy of the intestinal flora. Patent Document 1 shows that the amount of TI-SIgA in the intestinal tract decreases with aging, and a method for evaluating the amount of TI-SIgA associated with aging has been proposed.

[0004] On the other hand, Patent Document 2 proposes a composition for enhancing cellular immunity related to acquired immunity that contains γ-polyglutamic acid (γ-PGA). Patent Document 2 shows that γ-PGA has an effect of enhancing Th1 cell-mediated immunity via the TLR4 receptor, and that γ-PGA has an effect of increasing antigen presentation activity. However, Patent Document 2 does not mention that γ-PGA affects humoral immunity. Patent Document 3 shows that natto extract increases IgA production. However, there is no description of the mechanism of action, and the results are from in vitro tests using Peyer's patch cells, so it is unclear whether similar effects can be obtained in vivo. In addition, the IgA produced by Peyer's patch cells is TD-SIgA. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-001827 [Patent Document 2] Special Publication No. 2011-500554 [Patent Document 3] Japanese Patent Publication No. 2003-327540 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] TI-SIgA is thought to contribute to maintaining homeostasis of the gut microbiota and to be involved in maintaining intestinal immunity. Furthermore, while it is known that immune function declines with age, the inventors have revealed that TI-SIgA secretion also decreases with age. In other words, suppressing the decline in TI-SIgA secretion with age leads to suppressing the decline in immune function with age.

[0007] Therefore, the present invention aims to provide an antigen-nonspecific IgA secretion enhancer and a composition for enhancing antigen-nonspecific IgA secretion containing the antigen-nonspecific IgA secretion enhancer. [Means for solving the problem]

[0008] This disclosure includes the following aspects: [1] An antigen-nonspecific IgA secretion enhancer containing γ-polyglutamic acid or a salt thereof as an active ingredient. A composition for enhancing antigen-nonspecific IgA secretion, comprising the antigen-nonspecific IgA secretion enhancer described in [2][1] and a pharmaceutically acceptable carrier. [3] The antigen-nonspecific IgA secretion enhancing composition described in [2], used to suppress the decline in immune function associated with aging. [4] A composition for enhancing antigen-nonspecific IgA secretion according to [2] or [3], which is a pharmaceutical composition, food, feed or pet food. [Effects of the Invention]

[0009] According to the present invention, an antigen-nonspecific IgA secretion enhancer and an antigen-nonspecific IgA secretion enhancer composition containing the antigen-nonspecific IgA secretion enhancer are provided. [Brief explanation of the drawing]

[0010] [Figure 1] The results of a γ-PGA administration study using female DO11.10 mice are shown. The vertical axis represents the amount of secretory IgA (SIgA) in 100 mg of feces, with the value at the start of administration (16 weeks of age) set as 100%. The horizontal axis represents the time elapsed since the start of administration (16 weeks of age). [Figure 2] Figure 1 shows the amount of SIgA in 100 mg of feces before and after the γ-PGA administration test. [Modes for carrying out the invention]

[0011] <Antigen-Nonspecific IgA Secretion Enhancer> In one embodiment, the present invention provides an antigen-nonspecific IgA secretion enhancer comprising γ-polyglutamic acid or a salt thereof as an active ingredient.

[0012] "Antigen-nonspecific IgA" means IgA secreted regardless of the presence or absence of an antigen. Antigen-nonspecific IgA is produced via a T cell-independent pathway, has low antigen specificity, and is produced constantly. In this specification, antigen-nonspecific IgA is also denoted as "T cell-independent secretory IgA" or "TI-SIgA".

[0013] "Agent for enhancing the secretion of antigen-nonspecific IgA" (hereinafter also referred to as "TI-SIgA secretion enhancer") means a drug having the effect of enhancing the secretion amount of TI-SIgA. A TI-SIgA secretion enhancer particularly enhances the secretion of TI-SIgA in the intestinal mucosa. A TI-SIgA secretion enhancer has the effect of suppressing the decrease in the secretion amount of TI-SIgA associated with aging and maintaining the secretion amount of TI-SIgA. A TI-SIgA secretion enhancer may be an inhibitor of the decrease in the secretion amount of TI-SIgA associated with aging.

[0014] The TI-SIgA secretion enhancer of this embodiment contains γ-polyglutamic acid as an active ingredient. γ-Polyglutamic acid is a polypeptide having glutamic acid as a polymerization unit, and the carboxy group at the γ-position and the amino group at the α-position form a peptide bond. The structure of γ-polyglutamic acid is shown below (n is the number of repetitions). In this specification, γ-polyglutamic acid is also denoted as "γ-PGA".

[0015]

Chemical formula

[0016] The molecular weight of γ-PGA is not particularly limited. The molecular weight of γ-PGA used in the examples described later is 1000 kDa, but for example, it may be 50 kDa to 20,000 kDa, or 100 kDa to 15,000 kDa, or 1,000 kDa to 15,000 kDa.

[0017] γ-PGA may be composed only of L-form glutamic acid, may be composed only of D-form glutamic acid, or may be composed of L-form and D-form glutamic acid.

[0018] γ-PGA may be in the form of a salt. Examples of salts of γ-PGA include pharmaceutically acceptable salts of γ-PGA. The term "pharmaceutically acceptable salt" means a salt having a pharmacological action equivalent to that of γ-PGA. Examples of salts of γ-PGA include those in which some or all of the carboxy groups contained in γ-PGA are in the form of a salt. Examples of salts of γ-PGA include salts with alkali metals (e.g., sodium, potassium, etc.), salts with alkaline earth metals (e.g., magnesium, calcium, etc.), and the like.

[0019] The TI-SIgA secretion enhancer of the present embodiment can be administered to a subject in order to enhance the secretion amount of TI-SIgA. The administration target of the TI-SIgA secretion enhancer is not particularly limited. Examples of the administration target of the TI-SIgA secretion enhancer include mammals, such as humans, non-human primates (e.g., monkeys, chimpanzees, gorillas, marmosets, etc.), domestic animals (e.g., cows, pigs, goats, sheep, horses, etc.), pets (e.g., cats, dogs, rabbits, etc.), and rodents (e.g., mice, guinea pigs, rats, etc.), but are not limited thereto.

[0020] The TI-SIgA secretion enhancer of the present embodiment can be administered to a subject in the same manner as the TI-SIgA secretion enhancing composition described below. The administration route may be oral administration or parenteral administration. Parenteral administration is not particularly limited, and examples thereof include transdermal administration, rectal administration, arterial administration, intravenous administration, intradermal administration, subcutaneous administration, and the like.

[0021] The TI-SIgA secretion enhancer of the present embodiment may be formulated into pharmaceuticals, foods, and the like, and used to impart a TI-SIgA secretion enhancing function to those products. Products added with the TI-SIgA secretion enhancer of the present embodiment can be used as the antigen-nonspecific IgA secretion enhancing composition described below.

[0022] The TI-SIgA secretion enhancer of this embodiment can enhance the amount of TI-SIgA secreted, thereby suppressing the decline in TI-SIgA secretion due to aging. Therefore, it can suppress the decline in immune function due to aging. Furthermore, γ-PGA is an ingredient found in foods such as natto, and is highly safe with a low risk of side effects. Therefore, it is thought that administering it preventively from before old age can suppress the decline in TI-SIgA secretion in old age.

[0023] <Composition for enhancing antigen-nonspecific IgA secretion> In one embodiment, the present invention provides an antigen-nonspecific IgA secretion enhancing composition (hereinafter also referred to as "TI-SIgA secretion enhancing composition") containing the above-mentioned antigen-nonspecific IgA secretion enhancing agent and a pharmaceutically acceptable carrier.

[0024] A "pharmaceutically acceptable carrier" means a carrier that does not inhibit the physiological activity of the active ingredient and does not exhibit substantial toxicity to the target recipient. "Substantial toxicity" means that the ingredient does not exhibit toxicity to the target recipient at the doses normally used. Examples of pharmaceutically acceptable carriers are not limited to excipients, but include excipients, binders, disintegrants, lubricants, emulsifiers, stabilizers, diluents, oily bases, thickeners, antioxidants, reducing agents, oxidizing agents, chelating agents, solvents, etc. A pharmaceutically acceptable carrier may be used alone or in combination of two or more types.

[0025] The TI-SIgA secretion-enhancing composition may contain other components in addition to the above components. The other components are not particularly limited and can be appropriately selected depending on the intended use of the composition. Examples of other components include, but are not limited to, preservatives (e.g., antioxidants), chelating agents, flavoring and odor-masking agents, sweeteners, thickeners, buffering agents, and coloring agents.

[0026] The TI-SIgA secretion-enhancing composition may be a pharmaceutical composition, quasi-drug, food, functional food, or animal feed. The TI-SIgA secretion-enhancing composition can be administered to a subject to enhance the secretion of TI-SIgA. The amount of TI-SIgA secretion tends to decrease with age after 16 weeks of age, and is thought to constitute part of the decline in immune function associated with aging. Therefore, the TI-SIgA secretion-enhancing composition may be used to suppress the decline in immune function associated with aging.

[0027] (Pharmaceutical composition) The TI-SIgA secretion-enhancing composition may also be a pharmaceutical composition. If it is a pharmaceutical composition, any pharmaceutically acceptable carrier commonly used in the pharmaceutical field may be used without particular limitation. Examples of pharmaceutical excipients include, but are not limited to, preservatives (e.g., antioxidants), chelating agents, flavoring and odor-masking agents, sweeteners, thickeners, buffering agents, and coloring agents.

[0028] The dosage form of the pharmaceutical composition is not particularly limited and can be any dosage form commonly used for pharmaceutical preparations. The pharmaceutical composition of this embodiment may be an oral preparation or a parenteral preparation, but an oral preparation is preferred. Examples of oral preparations include tablets, coated tablets, pills, powders, granules, capsules, syrups, fine granules, liquids, drops, emulsions, etc. Examples of parenteral preparations include injections, suppositories, nasal sprays, enteral preparations, inhalants, etc. Pharmaceutical compositions of these dosage forms can be formulated according to standard methods (for example, methods described in the Japanese Pharmacopoeia).

[0029] The administration route of the pharmaceutical composition of this embodiment is not particularly limited and can be administered orally or parenterally, but oral administration is preferred. Parenteral administration routes include transdermal administration, intravenous administration, intranasal administration, subcutaneous administration, intradermal administration, intramuscular administration, intraperitoneal administration, and enteral administration.

[0030] The pharmaceutical composition can administer a therapeutically effective dose of the TI-SIgA secretion enhancer described above. "Therapeutically effective dose" means the amount of drug effective for treating or preventing the target disease. For example, the therapeutically effective dose of the TI-SIgA secretion enhancer may be an amount effective for enhancing TI-SIgA secretion. The therapeutically effective dose can be appropriately determined based on the symptoms, weight, age, and sex of the recipient, as well as the dosage form and method of administration of the pharmaceutical composition. For example, the single dose of γ-PGA in the pharmaceutical composition can be 0.001 to 1000 mg per kg of the recipient's body weight. The dose may also be 0.005 to 500 mg / kg, 0.01 to 300 mg / kg, 0.02 to 200 mg / kg, or 0.03 to 100 mg / kg.

[0031] The pharmaceutical composition may be administered as a single dose or as a repeated dose. In the case of repeated administration, the administration interval should be appropriately determined based on the patient's symptoms, weight, age, and sex, as well as the dosage form and method of administration of the pharmaceutical composition. For example, the administration interval may be every few hours, two to three times a day, once a day, once every two to three days, once a week, once a month, once every few months, etc.

[0032] The target recipients of the pharmaceutical composition are not particularly limited. Examples of target recipients of the pharmaceutical composition are the same as those for the TI-SIgA secretion enhancers described above.

[0033] (food) The TI-SIgA secretion-enhancing composition of this embodiment may be a food product. When the TI-SIgA secretion-enhancing composition is a food product, the above-mentioned TI-SIgA secretion-enhancing agent may be added to the food as a food additive. By adding the TI-SIgA secretion-enhancing agent to food, food products with TI-SIgA secretion-enhancing function (hereinafter also referred to as "TI-SIgA secretion-enhancing agent-contained food products") can be prepared. TI-SIgA secretion-enhancing agent-contained food products can be manufactured by adding the above-mentioned TI-SIgA secretion-enhancing agent to food ingredients and adding other food additives as appropriate, according to known methods corresponding to the type of food product.

[0034] In foods containing TI-SIgA secretion-enhancing properties, the type of food is not particularly limited. Examples of foods include: various types of noodles such as soba, udon, vermicelli, Chinese noodles, instant noodles, and cup noodles; carbohydrates such as bread, wheat flour, rice flour, pancakes, and mashed potatoes; beverages such as green juice, soft drinks, carbonated drinks, nutritional drinks, fruit drinks, vegetable drinks, lactic acid drinks, milk drinks, sports drinks, tea, and coffee; soy products such as tofu, okara, and natto; various types of soups such as curry roux, stew roux, and instant soup; frozen desserts such as ice cream, ice sherbet, and shaved ice; candy, cookies, gum, chocolate, and tablets. This includes, but is not limited to, snacks such as snack foods, biscuits, jellies, jams, creams, and other baked goods; processed seafood and livestock products such as kamaboko, hanpen, ham, and sausages; dairy products such as processed milk, fermented milk, butter, cheese, and yogurt; oils and processed oils such as salad oil, tempura oil, margarine, mayonnaise, shortening, whipped cream, and dressings; seasonings such as sauces, dressings, miso, soy sauce, and dips; and other processed foods such as various retort foods, furikake, and pickles.

[0035] In foods containing TI-SIgA secretion enhancers, the amount of TI-SIgA secretion enhancer is not particularly limited and can be set appropriately depending on the type of food. For example, considering the flavor of the food, the amount of TI-SIgA secretion enhancer in the food can be 0.001 to 30% by mass as γ-PGA. The amount of γ-PGA in the food may be 0.005 to 20% by mass, 0.01 to 15% by mass, 0.1 to 10% by mass, or 0.1 to 5% by mass, for example, from the viewpoint of the flavor of the food.

[0036] Foods containing TI-SIgA secretion enhancers may be functional foods or nutritional supplements. Functional foods or nutritional supplements may be in the form of general foods as described above, or in the form of dried powder, granules, tablets, jellies, drinks, etc. In this case, the TI-SIgA secretion enhancer may be mixed with other ingredients as appropriate and formed into dried powder, granules, tablets, jellies, drinks, etc., according to standard methods. Other ingredients are not particularly limited, and examples include pharmaceutically acceptable carriers. Examples of pharmaceutically acceptable carriers are the same as those listed above. In addition, sweeteners, flavoring agents, various seasonings, fragrances, oils and fats, and other food additives may be used as other ingredients to improve flavor, etc. Other ingredients may be used individually or in combination of two or more.

[0037] In functional foods or nutritional supplements, the content of TI-SIgA secretion enhancers is not particularly limited, and the content may be set appropriately depending on the type of functional food or nutritional supplement. For example, when a functional food or nutritional supplement is in the form of a dried powder, granules, tablets, etc., the γ-PGA content in the functional food or nutritional supplement may range from 0.01 to 99% by mass. The γ-PGA content in a functional food or nutritional supplement may be 0.1 to 90% by mass, 0.5 to 85% by mass, 1 to 85% by mass, or 1 to 85% by mass. When a functional food or nutritional supplement is in the form of a jelly, drink, etc., the TI-SIgA secretion enhancer content in the functional food or nutritional supplement may range from 0.05 to 80% by mass. The content of the TI-SIgA secretion enhancer in the functional food or nutritional supplement may be 0.1 to 75% by mass, 0.5 to 70% by mass, 1 to 60% by mass, or 1 to 50% by mass.

[0038] (Feed, pet food) The TI-SIgA secretion-enhancing composition of this embodiment may be animal feed or pet food. When the TI-SIgA secretion-enhancing composition of this embodiment is animal feed or pet food, the TI-SIgA secretion-enhancing agent may be added to the animal feed or pet food as a feed additive or pet food additive. By adding the TI-SIgA secretion-enhancing agent to animal feed or pet food, animal feed or pet food with TI-SIgA secretion-enhancing function (hereinafter also referred to as "TI-SIgA secretion-enhancing feed, etc.") can be prepared.

[0039] Feeds and other products that enhance TI-SIgA secretion can be manufactured by adding a TI-SIgA secretion enhancer to feed ingredients or pet food ingredients, and adding other feed additives or pet food additives as appropriate, according to known methods appropriate to the type of feed ingredients or pet food.

[0040] The types of animals that can be given TI-SIgA secretion-enhancing feed are not particularly limited. For example, mammals other than humans can be included. Specific examples include, but are not limited to, non-human primates (monkeys, chimpanzees, gorillas, marmosets, etc.), livestock (cattle, pigs, goats, sheep, horses, etc.), pets (cats, dogs, rabbits, etc.), and rodents (mice, guinea pigs, rats, etc.).

[0041] In feeds and the like that which are formulated to enhance TI-SIgA secretion, the content of the TI-SIgA secretion enhancer is not particularly limited, and the content can be set appropriately depending on the type of feed or pet food. For example, the content of the TI-SIgA secretion enhancer in feeds and the like that which are formulated to enhance TI-SIgA secretion is 0.001 to 90% by mass as the γ-PGA content. The content of the TI-SIgA secretion enhancer in feeds and the like that which are formulated to enhance TI-SIgA secretion is 0.005 to 20% by mass, 0.01 to 15% by mass, 0.1 to 10% by mass, or 0.1 to 5% by mass as the γ-PGA content. [Examples]

[0042] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0043] <Testing Method> The experiment was conducted based on the method described in Japanese Patent Publication No. 2021-001827. Specifically, female TCR transgenic mice with a fecal IgA level of 78 μg / 100 mg or higher at 16 weeks of age were selected, and the test substance administration test was performed between 16 and 28 weeks of age. Female mice with high fecal IgA levels at 16 weeks of age showed a high probability of a decrease in fecal IgA levels between 16 and 28 weeks of age. Therefore, it is considered that the ability of the test substance to enhance IgA secretion can be evaluated accurately with a smaller number of individuals.

[0044] (Test animals) As test animals, we used female DO11.10 mice (Jackson Laboratories), a breed in which most T cells express a TCR that responds to ovalbumin (OVA). The DO11.10 mice were housed in a standard SPF environment with 3-4 mice per cage. They were fed a commercially available standard diet (NMF; Oriental Yeast Co., Ltd.) and given free access to it. Water was also provided free access to it.

[0045] Fecal samples were collected from 16-week-old mice, and the amount of IgA in the feces was measured by ELISA. To prepare the ELISA sample, 1 mg of collected fecal was suspended in 10 μL of extraction buffer (ELISA Diluent (Thermo Fisher Scientific) with cOmplete®, EDTA-free (Roche Diagnostics) added) and centrifuged at 15000 g for 10 minutes at 4°C. After centrifugation, the supernatant was collected and used as the ELISA sample. ELISA was performed using the Mouse IgA ELISA Constructed Kit (Bethyl Laboratories, Inc).

[0046] Based on the results of the above measurements, mice with a fecal IgA level of 78 μg / 100 mg or higher were selected and used as test animals for the following administration tests.

[0047] (Administration study) γ-PGA (molecular weight approximately 1 million Da, Meiji Food Materia Co., Ltd.) was used as the test substance. In the γ-PGA administration group (13 animals), water containing 1% by mass of γ-PGA was freely available from 16 to 28 weeks of age. In the water administration group (12 animals), water was freely available from 16 to 28 weeks of age. Other rearing conditions were the same as described above. Between 16 and 28 weeks of age, fecal samples were collected from the test animals every two weeks, frozen and stored at -30°C until IgA extraction, and the amount of IgA in the feces was measured by ELISA.

[0048] <Result> The results are shown in Figures 1 and 2. Figure 1 shows the changes in fecal IgA levels (SIgA levels) after the start of the administration study. At weeks 2, 4, and 10, fecal IgA levels in the γ-PGA administration group were significantly higher than in the water administration group. Figure 2 compares the amount of IgA in feces (SIgA) before and after the start of the administration study. "Before" shows the amount before the start of the administration study (at 16 weeks of age), and "After" shows the amount after the start of the administration study (at 28 weeks of age). "Overall" shows the entire study population, including both the γ-PGA administration group and the water administration group. In the water administration group, a significant decrease in the amount of IgA in feces was observed after the start of the administration study compared to before the start of the study. This was thought to be due to a decrease in antigen-nonspecific IgA secretion with age. On the other hand, in the γ-PGA administration group, no significant decrease in the amount of IgA in feces was observed after the start of the administration study compared to before the start of the study. Therefore, it was suggested that the administration of γ-PGA suppressed the decrease in antigen-nonspecific IgA secretion with age. [Industrial applicability]

[0049] According to the present invention, an antigen-nonspecific IgA secretion enhancer and an antigen-nonspecific IgA secretion enhancer composition containing the antigen-nonspecific IgA secretion enhancer are provided.

Claims

1. An antigen-nonspecific IgA secretion enhancer containing γ-polyglutamic acid or a salt thereof as an active ingredient.

2. A composition for enhancing antigen-nonspecific IgA secretion, comprising the antigen-nonspecific IgA secretion enhancer described in claim 1 and a pharmaceutically acceptable carrier.

3. A composition for enhancing antigen-nonspecific IgA secretion according to claim 2, used to suppress the decline in immune function associated with aging.

4. A composition for enhancing antigen-nonspecific IgA secretion according to claim 2 or 3, which is a pharmaceutical composition, food, feed, or pet food.

Images