Agents for preventing infectious diseases and health food containing the same

Abstract

To provide a substance for inducing a specific substance (group) in the body for the activation of an innate immune mechanism, and to provide a new therapeutic agent for infectious diseases and a new health food.SOLUTION: Provided are: an infectious disease-preventing agent which is a substance that, when administered into the body, induces production of an antimicrobial peptide in the body to prevent an infectious disease, the substance being an oligosaccharide composed mainly of mannose and having 2 or more and 10 or less molecules of monosaccharides bonded to each other; a health food or innate immunity activator containing the infectious disease-preventing agent; and an infectious disease-preventing agent which is obtained by administering a specific oligosaccharide to the body, the infectious disease-preventing agent preventing infectious disease caused by a pathogen by activating an innate immune function in the body and inducing an antimicrobial peptide.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an infectious disease preventive agent, and more specifically, to an infectious disease preventive agent that prevents infectious diseases caused by pathogens by a newly discovered specific mechanism, and a health food containing the same. [Background technology]

[0002] Antimicrobial peptides were first discovered in insects as peptides with antimicrobial activity in vitro, and have since been shown to exist in mammals, including humans.

[0003] There are two types of immunity: adaptive immunity and innate immunity. Adaptive immunity is a defense mechanism mediated by antibodies, which does not exist in invertebrates. Invertebrates defend themselves against infections solely through innate immunity. For example, insects, which are invertebrates, are known to have resistance to infection without developing antibodies, and this resistance may be mediated by enhanced humoral immunity or activation of cellular immunity.

[0004] The above mechanism is thought to exist in mammals, including humans, but its actual state and molecular mechanism remain unclear. Research into the molecular mechanism of immune priming has progressed in the insects Drosophila melanogaster and silkworm. In Drosophila melanogaster, the involvement of the Toll pathway has been suggested, and in silkworms, activation of the Imd pathway and production of antimicrobial peptides have been shown, but the detailed molecular mechanism and application of its effects as an agent are unknown.

[0005] On the other hand, mannooligosaccharides are known to have several effects on humans. Patent Document 1 describes that mannooligosaccharides act on macrophages to produce cytokines and chemokines, in particular by increasing the amount of interleukin 12 produced, thereby increasing immune activity. However, Patent Document 1 does not contain any description of so-called "antimicrobial peptides," and only describes a conventional immunostimulant that utilizes the mechanism of natural immunity.

[0006] Patent Document 2 describes a method for producing a mannooligosaccharide-containing substance, and states that the substance has an immunostimulatory effect. However, the "immunostimulatory effect" mentioned here is just one of many listed effects, there are no examples of the immunostimulatory effect, and the effect remains merely a wishful thinking.

[0007] Patent Document 3 describes a skin quality improving agent containing, as an active ingredient, an oligosaccharide in which 1 to 10 molecules of mannose-based monosaccharide are bonded together. However, Patent Document 3 contains no description about so-called "antimicrobial peptides" or about immune activity.

[0008] Patent Document 4 describes a diacylglycerol acyltransferase inhibitor containing, as an active ingredient, an oligosaccharide in which 1 to 10 molecules of mannose-based monosaccharide are linked together. However, Patent Document 4 contains no description about so-called "antimicrobial peptides" or about immune activity.

[0009] Antibacterial agents and antibiotics are the mainstream countermeasures against infectious diseases. Although there are hopes for other countermeasures, they are still insufficient. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2005-035896 A [Patent Document 2] JP 2011-132187 A [Patent Document 3] JP 2015-189738 A [Patent Document 4] JP 2015-189747 A Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above-mentioned background art, and an object of the present invention is to find a new mechanism for activating the innate immune mechanism and to provide an agent that induces the mechanism in the body. Another object of the present invention is to provide a health food containing said agent. [Means for solving the problem]

[0012] As a result of extensive research aimed at solving the above problems, the present inventors discovered that specific oligosaccharides effectively induce and produce "antimicrobial peptides" related to the above-mentioned new mechanism in the body, thereby preventing infectious diseases, and thus completed the present invention.

[0013] In other words, the present invention provides an infectious disease preventive agent that, when administered to the body, induces the production of antimicrobial peptides in the body and prevents infectious diseases, and is characterized in that the substance is an oligosaccharide composed mainly of mannose and consisting of two to ten monosaccharide molecules linked together.

[0014] The present invention also provides the infectious disease preventive agent, wherein the oligosaccharide is an oligosaccharide to which only mannose is bound, or an "oligosaccharide to which one or more monosaccharides selected from the group consisting of glucose, galactose and fructose are bound in an amount of 20 unit% or less relative to the total units of the oligosaccharide."

[0015] The present invention also provides the aforementioned infectious disease preventive agent, wherein the oligosaccharide is obtainable by hydrolyzing mannan.

[0016] The present invention also provides the infection preventive agent, wherein the mannan is contained in coffee beans and / or coffee extract residue.

[0017] The present invention also provides an infectious disease preventive agent that is administered into the body before the pathogen of the infectious disease enters the body, before the body becomes infected with the pathogen, or before the infectious disease develops.

[0018] The present invention also provides the above-mentioned infectious disease preventive agent, which is administered into the body "during a period of not less than 1 hour and not more than 3 days" before the pathogen of the infectious disease enters the body.

[0019] The present invention also provides a health food comprising the above-mentioned infectious disease preventive agent.

[0020] The present invention also provides a natural immunity activator that is characterized by being an infectious disease preventive agent as described above. Effect of the Invention

[0021] The present inventors have discovered that "oligosaccharides consisting of 2 to 10 mannose-based monosaccharide molecules linked together" (hereinafter, the text in parentheses may be abbreviated as "specific oligosaccharides") favorably induce and produce "antimicrobial peptides" in the body, thereby preventing infectious diseases.

[0022] Since the mechanisms and actions of so-called "antimicrobial peptides" are thought to be common to arthropods such as silkworms and vertebrates such as humans, what has been demonstrated in silkworms is highly likely to also apply to humans.

[0023] As a result, we invented a new substance (health food, agent, etc.) called an "infectious disease prevention agent that prevents infectious diseases by activating so-called 'antibacterial peptides' that are induced in the body when administered."

[0024] Based on the discovery of the above mechanism, we have invented a new substance (health food, agent, etc.) called "an infection preventive agent that is administered to the body before a pathogen enters the body, before the body is infected with a pathogen, or before the onset of an infectious disease." Furthermore, we have invented a new substance (health food, agent, etc.) called "an infection preventive agent that is administered to the body in advance for a period of 'one hour to three days' before a pathogen enters the body."

[0025] The specific oligosaccharides of the present invention are naturally derived and can be used safely. Therefore, the infectious disease preventive agent of the present invention can be ingested or eaten before a pathogen enters the body or when one is likely to be infected by the pathogen, such as when an infectious disease is prevalent; when entering an area where an infectious disease is prevalent; when one is tired or otherwise thought to have a weakened resistance; or when one wants to constantly prevent infectious diseases, thereby preventing infection with the infectious disease or the onset of the infectious disease.

[0026] According to the present invention, by ingesting specific oligosaccharides, so-called "antimicrobial peptides" that exert the above-mentioned effects through the above-mentioned mechanisms and actions are suitably induced in the body, thereby making it possible to prevent infectious diseases. [Brief description of the drawings]

[0027] [Figure 1] 1 is a graph showing changes in gene expression in fat bodies of silkworms to which a specific oligosaccharide was administered intravascularly in Evaluation Example 1. [Diagram 2] FIG. 1 is a photograph showing the results of Western blotting using an antibody that recognizes cecropin, which shows that cecropin was induced in the blood of silkworms that had been administered a specific oligosaccharide. [Diagram 3] 1 is a graph showing the results of administering a specific oligosaccharide, administering Pseudomonas aeruginosa 6 hours later, and measuring the number of surviving silkworms (survival rate (%)) 24 hours later. Death of silkworms caused by Pseudomonas aeruginosa infection was suppressed in a concentration-dependent manner by the specific oligosaccharide. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The present invention will be described below, however, the present invention is not limited to the specific embodiments below and can be modified as desired within the scope of the technical concept.

[0029] The infectious disease prevention agent of the present invention is a substance that, when administered to the body, induces the production of antimicrobial peptides in the body and prevents infectious diseases, and is characterized in that the substance is an "oligosaccharide composed mainly of mannose, with two to ten monosaccharide molecules linked together."

[0030] In other words, the infectious disease preventive agent of the present invention is an infectious disease preventive agent containing a substance that induces antimicrobial peptides in the body when administered to the body, The substance is characterized as being an "oligosaccharide in which 2 to 10 mannose-based monosaccharide molecules are linked together."

[0031] Hereinafter, the above-mentioned contents in parentheses may be abbreviated as simply "specific oligosaccharide" or "oligosaccharide".

[0032] In other words, the present invention provides an infectious disease preventive agent that contains a specific oligosaccharide and prevents an infectious disease caused by a pathogen, comprising: The infectious disease preventive agent is an infectious disease preventive agent which, when administered into the body, activates the body's natural immune function and induces antimicrobial peptides, thereby preventing infectious diseases.

[0033] <Definition of "antimicrobial peptides" (so-called "antimicrobial peptides")> In this specification and the like, the above-mentioned "antimicrobial peptide" refers to a substance that is known as an "antimicrobial peptide" at the time of filing of this application. That is, the so-called "antimicrobial peptide" is a general term for peptides that function as a type of evolutionarily conserved immune response, and is generally thought to directly attack bacterial bodies as effector molecules. Specifically, the so-called "antimicrobial peptide" is said to exhibit antimicrobial effects by damaging the bacterial cell membrane, by inhibiting the action of the bacterial protein synthesis system or specific enzymes, or by directly attacking bacteria, so the so-called "antimicrobial peptide" refers to such peptides.

[0034] The pathogens causing infectious diseases that are prevented by the so-called "antimicrobial peptides" of the present invention are not limited to bacteria, but include all pathogenic microorganisms, such as bacteria, fungi, and viruses.

[0035] <Definition of oligosaccharides (specific oligosaccharides)> The "oligosaccharide" in the present invention is a "specific oligosaccharide", which means an "oligosaccharide in which 2 to 10 mannose-based monosaccharide molecules are linked together". Here, the term "mainly composed of mannose" means that 50% or more of all the monosaccharide units constituting one particular oligosaccharide are mannose units. Preferably, the oligosaccharide contains 60 unit % or more, more preferably 70 unit % or more, further preferably 80 unit % or more, and particularly preferably 90 unit % or more of mannose.

[0036] The term "specific oligosaccharide" is not limited to "an oligosaccharide containing 2 to 10 mannose molecules only," but refers to "an oligosaccharide containing 2 to 10 mannose molecules of any monosaccharide mainly composed of mannose."

[0037] Examples of monosaccharides constituting the specific oligosaccharide include mannose, glucose, galactose, and fructose. In the infectious disease preventive agent of the present invention, the specific oligosaccharide is preferably an oligosaccharide to which only mannose is bound, or an "oligosaccharide to which one or more monosaccharides selected from the group consisting of glucose, galactose and fructose are bound, preferably in an amount of 20 unit% or less, and particularly preferably 10 unit% or less, relative to the total units of the oligosaccharide." In addition, in the infectious disease preventive agent of the present invention, the specific oligosaccharide is preferably an oligosaccharide to which only mannose is bound, or an oligosaccharide to which fructose is bound, preferably in an amount of 20 unit% or less, and particularly preferably 10 unit% or less, relative to the total units of the oligosaccharide.

[0038] In the present invention, when referring to an "infection preventive agent containing a specific oligosaccharide," the infection preventive agent may contain, in addition to containing "an oligosaccharide in which 2 to 10 molecules of a monosaccharide mainly composed of mannose are bonded together (specific oligosaccharide)," monosaccharides such as mannose, glucose, galactose, fructose, etc.; polysaccharides in which 11 or more molecules (11 or more units) of monosaccharides are bonded together; oligosaccharides in which less than 50 unit% of mannose is bonded; etc.

[0039] In this specification, the degree of polymerization of an oligosaccharide may be expressed as "DP". "DP" refers to the number of monosaccharides (units) that constitute the oligosaccharide. That is, for example, a specific oligosaccharide composed of only four mannose units is expressed as "DP4".

[0040] When the ratio of mannose to all units (all constituent sugars) is equal to or higher than the above, so-called "antimicrobial peptides" can be suitably induced in the body, and the above-mentioned effects of the present invention can be suitably obtained. In addition, since the binding ratio of other monosaccharides such as glucose is sufficiently low, the sweetness and the like can be kept low, making it easy to apply to a wide range of foods and beverages, supplements, health foods, medicines, and the like.

[0041] The specific oligosaccharide in the present invention is an oligosaccharide in which 2 to 10 monosaccharide molecules are bonded together, but is not limited thereto. An oligosaccharide in which 2 to 8 monosaccharide molecules are bonded together is more preferable, and an oligosaccharide in which 3 to 7 monosaccharide molecules are bonded together is particularly preferable.

[0042] In addition, the specific oligosaccharide is preferably one in which the monosaccharides constituting it are linked by β-1,4 bonds. In the infectious disease preventive agent of the present invention, the oligosaccharide, i.e., the specific oligosaccharide is preferably β-1,4-mannooligosaccharide, since it can suitably induce so-called "antibacterial peptides" in the body and can more suitably obtain the above-mentioned effects of the present invention.

[0043] <Specific oligosaccharides obtained by hydrolysis of mannan> The specific oligosaccharide in the present invention is preferably one obtained by hydrolyzing mannan. In this specification, "mannan" includes not only polysaccharides having only D-mannose as a constituent unit, but also galactomannan, glucomannan, and the like, which are polysaccharides having mannose and "galactose or glucose" as constituent units.

[0044] Mannan is contained in, for example, coffee beans, seaweed, elephant palm fruit, coconut palm fruit, tsukuneimo, yam, konjac root, lily, daffodil, red spider lily, locust bean gum, guar gum, etc., and can be obtained by extraction from them. From the obtained mannan, specific oligosaccharides can be obtained by general hydrolysis, acid hydrolysis, high-temperature thermal hydrolysis, enzymatic hydrolysis, hydrolysis by microbial fermentation, or the like. It is also preferable to carry out the extraction and hydrolysis simultaneously, that is, during the extraction, hydrolysis can be carried out under high temperature and pressure to obtain specific oligosaccharides.

[0045] Methods of hydrolysis using an acid and / or high temperature are disclosed in JP-A-61-96947 and JP-A-2-200147. By adjusting the reaction time and reaction temperature and solubilizing and hydrolyzing the mannan, for example, mannan with a DP of 10 to 40 can be suitably obtained.

[0046] Although not limited thereto, it is preferable to obtain specific oligosaccharides by purifying the extracted and / or hydrolyzed product using a method such as activated carbon treatment, adsorption resin treatment, ion exchange resin treatment, or ion exchange membrane treatment. It is also preferable to increase the ratio of mannose in the specific oligosaccharides in the above purification step.

[0047] As described above, the mannan that is the raw material for the specific oligosaccharides is obtained, for example, from coffee beans, and the coffee beans that are the subject of extraction include raw coffee beans, roasted coffee, ground roasted coffee, and the residue from coffee extraction (as a beverage).

[0048] Among these, the mannan is preferably that contained in coffee beans and / or coffee extraction residue. When ground roasted coffee is extracted in a commercial extractor, the galactose side chains of the galactomannan in the roasted coffee are solubilized, and the arabinogalactan is solubilized by hydrolysis. Therefore, the coffee extraction residue is rich in mannans and has a linear structure. For this reason, the mannan contained in coffee beans and / or coffee extraction residue is extremely suitable as a raw material for specific oligosaccharides.

[0049] <Infectious disease prevention agent> The infectious disease preventive agent of the present invention contains a substance that induces so-called "antimicrobial peptides" in the body when administered to the body, and prevents infectious diseases caused by pathogens. In addition, the infection prevention agent of the present invention contains a specific oligosaccharide and prevents infection caused by a pathogen, and when administered to the body, the infection prevention agent activates the body's natural immune function and induces antibacterial peptides, thereby preventing infection.

[0050] As described in the Examples, the infectious disease preventive agent of the present invention has the following features and was invented based on the following experimental results and findings. Furthermore, since the mechanisms and actions of antimicrobial peptides are generally believed to be common (conserved) between arthropods such as silkworms and vertebrates such as humans, what has been demonstrated in silkworms is highly likely to also apply to humans.

[0051] The specific oligosaccharides showed a preventive effect against Pseudomonas aeruginosa infection when administered into the bloodstream of silkworms (see, for example, Figure 3).

[0052] In the fat body of silkworms that had received specific oligosaccharides intravenously, increased expression of genes related to innate immunity, including antimicrobial peptides, was induced (Table 1, Figure 1). This suggests that administering specific oligosaccharides to the body can activate the body's natural immune function and induce antimicrobial peptides (see, for example, Figure 2), thereby preventing infections caused by pathogens.

[0053] The present invention is an agent for preventing infections, in other words, an agent for pre-oral administration, an agent for preventing infections by activating natural immunity, and an antimicrobial peptide inducer.

[0054] <<Anti-infectious disease prevention agent to be taken before a specific period>> The infectious disease preventive agent of the present invention is an infectious disease preventive agent that is administered into the body before a pathogen enters the body, before infection with the pathogen, or before the onset of the infectious disease. In other words, the present invention is an infectious disease preventive agent for pre-administration. As shown in Evaluation Example 1, in silkworms, so-called "antibacterial peptides" (cecropins) were detected in the body 6 hours after administration of specific oligosaccharides (see Figure 2). In addition, silkworms developed resistance to a pathogen (Pseudomonas aeruginosa) six hours after administration of a specific oligosaccharide (see Figure 3).

[0055] Since the action and mechanism of so-called "antimicrobial peptides" are thought to be common between silkworms and humans, it is highly likely that humans will also develop pathogen resistance after a similar period of time after administration of specific oligosaccharides as silkworms. In the evaluation examples, the agent was administered into the blood of silkworms, but the agent can also be administered orally. Taking into account the time it takes for the agent to move from the digestive system to the circulatory system in the body, and also the time it takes for the pathogen to be taken into the body after contact with the pathogen, the agent of the present invention is an agent for preventing infection that is preferably taken during the following period before contact with the pathogen:

[0056] The "infection prevention agent containing a specific oligosaccharide" of the present invention is preferably administered into the body "for a period of not less than 1 hour and not more than 3 days" before a pathogen enters the body. More preferably, it is administered "between 1.5 hours and 1 day (24 hours)" before the pathogen enters the body, even more preferably "between 2 hours and 12 hours", particularly preferably "between 3 hours and 10 hours", and most preferably "between 4 hours and 8 hours".

[0057] Conventionally, when simply referring to a "natural immune activator," no one would think of the desirability of specifying the administration period or timing. Therefore, both the infectious disease preventive agent of the present invention described above and the health food and general food of the present invention described below are different "substances" from a mere "natural immune activator containing a specific oligosaccharide."

[0058] <Use of drugs, health foods, general foods, etc., other ingredients, and subjects> The present invention also relates to a natural immunity activator characterized by being an infectious disease preventive agent based on its action and mechanism. The present invention also relates to an oral preparation, particularly a health food or general food, which contains the above-mentioned infectious disease preventive agent.

[0059] <<Other Ingredients>> In the present invention, the infectious disease preventive agent of the present invention can be prepared by adding (containing) other ingredients to the specific oligosaccharide, which is the active ingredient. The above-mentioned "other components" include the above-mentioned monosaccharides such as mannose, glucose, galactose, fructose, etc.; polysaccharides in which 11 or more molecules (11 or more units) of monosaccharides are bonded; oligosaccharides in which less than 50 unit% of mannose is bonded; and the like. In addition, other components can be appropriately selected depending on the purpose within a range that does not impair the effects of the present invention, and examples of such components include carriers, compounding agents, etc. that are acceptable for drugs, health foods, etc.

[0060] Such a carrier is not particularly limited and can be appropriately selected depending on, for example, the dosage form described below. Furthermore, the content of "other ingredients" is also not particularly limited and can be appropriately selected depending on the purpose.

[0061] The dosage form of the health food of the present invention is not particularly limited and can be appropriately selected depending on the desired administration method, for example, as described below. Specific examples include oral solid preparations such as tablets, coated tablets, granules, powders (dust), and capsules; oral liquid preparations such as oral liquid preparations, syrups, and elixirs; and the like.

[0062] Examples of the "other ingredients" for the above-mentioned tablets, coated tablets, and granules include excipients, binders, disintegrants, lubricants, colorants, flavorings, and odorants.

[0063] Examples of the excipient include lactose, sucrose, sodium chloride, glucose, starch, calcium carbonate, kaolin, microcrystalline cellulose, silicic acid, and the like. Examples of the binder include water, ethanol, propanol, simple syrup, glucose solution, starch solution, gelatin solution, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl starch, methyl cellulose, ethyl cellulose, shellac, calcium phosphate, polyvinylpyrrolidone, and the like. Examples of the disintegrants include dry starch, sodium alginate, agar powder, sodium hydrogen carbonate, calcium carbonate, sodium lauryl sulfate, monoglyceride stearate, lactose and the like. Examples of the lubricant include talc, stearates, borax, polyethylene glycol, and the like. Examples of the colorant include titanium oxide and iron oxide. Examples of the flavoring and / or fragrance agent include white sugar, orange peel, citric acid, tartaric acid, and the like.

[0064] Examples of the "other ingredients" for the powder (dusting agent) include flow improvers (anti-caking agents), stabilizers, preservatives, sweeteners, flavorings, coloring agents, etc.

[0065] "Other ingredients" for the capsules include edible oils, thickeners, etc. Also included are those mentioned above.

[0066] Examples of the "other ingredients" for the oral liquid preparation include suspending agents, emulsifying agents, thickening agents, flavorings, odorants, buffers, stabilizers, pH adjusters, solubilizing agents, preservatives, fragrances, coloring agents, etc.

[0067] Examples of the flavoring and / or fragrance agent include white sugar, orange peel, citric acid, tartaric acid, and the like. Examples of the stabilizer include tragacanth, gum arabic, and gelatin. Examples of the pH adjuster and the buffer include sodium citrate, sodium acetate, and sodium phosphate. Examples of the stabilizer include sodium pyrosulfite, EDTA, thioglycolic acid, and thiolactic acid. Examples of the preservatives include methyl parahydroxybenzoate, ethyl parahydroxybenzoate, and propyl parahydroxybenzoate.

[0068] <<Target of administration>> Examples of subjects to which the infectious disease preventive agent of the present invention can be administered include humans; mice; monkeys; horses; livestock such as cows, pigs, goats, sheep, and chickens; and pets such as cats, dogs, rabbits, turtles, and snakes.

[0069] <<Dosage>> The dosage of the infectious disease prevention agent of the present invention is not particularly limited and can be appropriately selected depending on the age and body weight of the individual to be administered, the degree of the desired effect, the method of administration, etc., but for example, the oral dosage for a single administration to an adult is preferably 1 mg to 30 g, more preferably 10 mg to 10 g, and particularly preferably 100 mg to 3 g, in terms of the amount of specific oligosaccharide (converted into the amount).

[0070] When simply referring to a "natural immune activator," the long-term dosage or daily dosage should be specified, and the single dosage is not specified as a preventative measure to predict infection. Therefore, both the infectious disease preventive agent of the present invention and the health food and general food of the present invention are different "substances" from a simple "natural immune activator containing a specific oligosaccharide."

[0071] The infectious disease preventive agent of the present invention is composed mainly of oligosaccharides and can be safely taken orally. The infectious disease preventive agent of the present invention is used as a medicine, health food, food and drink, or general food, or is used by being mixed with them.

[0072] <How to prevent infectious diseases> A preferred method for implementing the present invention is a method for preventing infectious diseases, which is characterized by administering to the body "an oligosaccharide (specific oligosaccharide) composed of 2 to 10 mannose-based monosaccharide molecules linked together" and activating the body's natural immune function with the oligosaccharide and inducing antimicrobial peptides, thereby preventing infectious diseases caused by pathogens.

[0073] Furthermore, a preferred method for implementing the present invention is the above-mentioned method for preventing infectious diseases, in which the oligosaccharide is administered to the body "for a period of at least one hour and not more than three days" before the pathogen enters the body to induce antimicrobial peptides, thereby preventing infection caused by the pathogen. The more preferable range, the even more preferable range, the particularly preferable range, and the most preferable range of the "period of 1 hour or more and 3 days or less" are as described above. EXAMPLES

[0074] The present invention will be described in detail below based on examples, but the present invention is not limited to the specific scope of the following examples.

[0075] Preparation Example 1 <Preparation of specific oligosaccharides> The "oligosaccharides (specific oligosaccharides) in which 2 to 10 mannose-based monosaccharide molecules are linked together" were prepared as follows. That is, a slurry consisting of 14 parts by mass of coffee extraction residue (average particle size: approximately 1 mm) and 86 parts by mass of pure water was heat-treated using a 4 m thermal plug flow reactor. In the heat treatment, the slurry was pumped with high pressure steam into a thermal plug flow reactor at a rate that gave a residence time in the reactor of 8 minutes and maintained at 210° C. for 8 minutes using a 6.35 mm φ orifice.

[0076] The reaction was then terminated by spraying the slurry under atmospheric pressure. The resulting slurry was filtered to separate insoluble solids and to separate a liquid containing soluble solids. The liquid containing the soluble solids was decolorized with activated carbon and then with an adsorption resin, and further desalted with an ion exchange resin, and then concentrated and dried to obtain a composition containing the desired specific oligosaccharide.

[0077] The degree of polymerization (DP) distribution of the specific oligosaccharide thus obtained was DP2: 26.6%, DP3: 20.2%, DP4: 17.8%, DP5: 10.9%, DP6: 8.9%, DP7: 6.0%, DP8: 3.6%, DP9: 1.9%, and DP10: 1.7%, and the proportion of mannose in the total monosaccharide units constituting the specific oligosaccharide as a whole was 90 unit%. DP1 was 2.4%.

[0078] The distribution of DP and the amount of mannose in the sugar chain can take various values depending on the hydrolysis conditions. For DP1, it is mannose etc., for DP2, it is mannobios etc., for DP3, it is mannotriose etc., for DP4, it is mannotetraose etc., for DP5, it is mannopentaose etc., for DP6, it is mannohexaose etc., for DP7, it is mannoheptaose etc., for DP8, it is mannoctaose etc., for DP9, it is mannononaose etc., for DP10, it is mannodecaose etc., and the linkage pattern was β-1,4 linkage.

[0079] Evaluation Example 1 [[Evaluation Method]] <Object of Evaluation> As the object of evaluation, the specific oligosaccharide prepared in Preparation Example 1 (an oligosaccharide in which 2 to 10 monosaccharides mainly composed of mannose are bound) was used.

[0080] <Silkworms as Experimental Animals> As experimental animals, silkworms of the Fuyo × Tsukuba strain eggs were purchased and reared until the 4th instar using artificial feed containing antibiotics. For the experiment, 4th instar silkworms were separated, and on the next day (i.e., the 1st day of the 5th instar), they were given feed without antibiotics, and silkworms on the 2nd day of the 5th instar were used.

[0081] <Transcriptome Analysis by RNA-seq Method> Silkworms injected with 50 μL of a specific oligosaccharide solution (hereinafter abbreviated as "specific oligosaccharide sample") dissolved at a concentration of 1.0 mg / mL in physiological saline, and silkworms injected with 50 μL of physiological saline were reared at 27°C for 6 hours. Then, the fat bodies of each silkworm were excised and total RNA was extracted.

[0082] After preparing a cDNA library by reverse transcription reaction from the extracted RNA, cDNA derived from mRNA was recovered using oligo dT beads. Then, sequence analysis was performed using a next-generation sequencer. The number of samples was 3 individuals per group, and the experiment was conducted for each individual. Based on the obtained results, data analysis was performed.

[0083] <Verification of survival rate of silkworms pretreated with specific oligosaccharides after being challenged with Pseudomonas aeruginosa> The above specific oligosaccharide samples were injected into the blood vessels of silkworms at various concentrations, and the silkworms were raised at 27°C for 6 hours. Then, a viable suspension of Pseudomonas aeruginosa (10% of overnight culture) was 6 The silkworms were then cultured at 37°C for 24 hours and the number of survivors was recorded.

[0084] [[Evaluation Results]] <Results of transcriptome analysis in the fat body of silkworms after intravenous injection of specific oligosaccharides> Figure 1 shows the results of principal component analysis performed based on the expression patterns of approximately 16,000 genes. The horizontal axis shows the first principal component (PC1), and the vertical axis shows the second principal component (PC2).

[0085] In FIG. 1, each plot represents the results for each individual, with "●" representing the results for the saline-administered group (control) and "▲" representing the results for the group administered with a specific oligosaccharide sample. Different regions in FIG. 1 correspond to different gene expression patterns, indicating that the gene expression patterns were altered by administration of a particular oligosaccharide sample. As shown in FIG. 1, changes in gene expression patterns were observed in the fat bodies of silkworms that had received specific oligosaccharides intravenously, compared to silkworms that had received saline.

[0086] Furthermore, genes that showed a statistically significant increase in expression of 10-fold or more were individually searched for. Table 1 shows the genes whose expression was increased by more than 10-fold in the fat bodies of silkworms that had received specific oligosaccharides into their bloodstream. The genes shown in bold in Table 1 are innate immunity-related genes. As can be seen from Table 1, increased expression of genes including those related to innate immunity was observed.

[0087] [Table 1]

[0088] <Detection of cecropins in the blood of silkworms after intravenous injection of specific oligosaccharides> We examined by Western blotting using an antibody that recognizes cecropin B whether cecropin B, a so-called "antibacterial peptide," was expressed and induced in the blood of silkworms administered with the above-mentioned specific oligosaccharide sample.

[0089] Physiological saline or a specific oligosaccharide sample was administered intravenously to 5th instar silkworms on the 2nd day of instar, and blood was collected from the silkworms after the times shown in Figure 2 (0, 1, 3, and 6 hours). 15 μL of pooled blood plasma was applied and electrophoresis was performed. Western blots were performed to examine bands detected with antibodies against cecropin.

[0090] As a result, as shown in FIG. 2, when a specific oligosaccharide sample (50 mg / larva) was administered into the hemocoel of silkworms, cecropin was detected only in the blood of silkworms 6 hours after administration. Cecropin was not detected up to 3 hours after administration of the specific oligosaccharide sample.

[0091] <Examination of whether specific oligosaccharides confer resistance to Pseudomonas aeruginosa to silkworms by pre-administration> Focusing on the possibility that specific oligosaccharides are signal molecules that activate the innate immune system of silkworms, we performed an infection experiment in which specific oligosaccharides were pre-administered 6 hours before inoculation with the pathogen. The results are shown in Figure 3.

[0092] The horizontal axis of Figure 3 represents the dosage (mg / g of individual) of a specific oligosaccharide administered into the blood of silkworms, and the vertical axis of Figure 3 represents the survival rate (%) of silkworms 24 hours after pathogen injection (average of n=4). The pathogen used was Pseudomonas aeruginosa (PA01).

[0093] As a result, as can be seen from Figure 3, the silkworms pre-administered with the specific oligosaccharide acquired resistance to infection with Pseudomonas aeruginosa as the dose increased. In other words, the pre-administration of the specific oligosaccharide conferred resistance to Pseudomonas aeruginosa infection to the silkworms.

[0094] [[Discussion of evaluation results]] It has been shown that administration of specific oligosaccharides into the blood of silkworms can confer resistance to Pseudomonas aeruginosa infection. Although only intravascular administration was performed in the study of Evaluation Example 1, it is expected that a specific oligosaccharide sample that is effective when taken orally can be obtained. In particular, for low molecular weight oligosaccharides (oligosaccharides with a small number of bond units), it is fully expected that a specific oligosaccharide sample that is effective when taken orally can be obtained by increasing the absorption from the intestinal tract.

[0095] To explore the mechanism by which specific oligosaccharides confer resistance to Pseudomonas aeruginosa infection, we analyzed gene expression patterns in the fat bodies of silkworms administered specific oligosaccharides by RNA sequencing. As a result, it was found that the expression of multiple innate immunity-related genes increased, including so-called "antimicrobial peptide genes" such as cecropin. This is consistent with the fact that cecropin was induced in the blood of silkworms administered specific oligosaccharides. [Industrial Applicability]

[0096] The present invention provides an "infectious disease preventive agent with a new method of ingestion and administration" resulting from a new mechanism, action and mode of action, and therefore the present invention can be widely used in the fields of manufacture, sale, use, etc. of pharmaceuticals, health foods, general foods, etc., or as raw materials thereof.

Claims

1. An infectious disease prevention agent characterized in that, when administered into the body, it induces the production of antimicrobial peptides in the body and prevents infectious diseases, and the substance is an oligosaccharide composed mainly of mannose, and is composed of two or more and ten or less monosaccharide molecules linked together.

2. The infection prevention agent according to claim 1, wherein the oligosaccharide is an oligosaccharide to which only mannose is bound, or an oligosaccharide to which one or more monosaccharides selected from the group consisting of glucose, galactose and fructose are bound in an amount of 20 unit% or less relative to the total units of the oligosaccharide.

3. The infection preventive agent according to claim 1, wherein the oligosaccharide is a β-1,4-mannooligosaccharide.

4. 2. The infection preventive agent according to claim 1, wherein the oligosaccharide is obtained by hydrolyzing mannan.

5. The infection preventive agent according to claim 4, wherein the mannan is contained in coffee beans and / or coffee extract residue.

6. The infectious disease preventive agent according to claim 1 , wherein the pathogen of the infectious disease is a bacterium, a fungus, or a virus.

7. The infection prevention agent according to claim 6, which is administered into the body before the pathogen enters the body, before infection with the pathogen, or before the infection develops.

8. The infection preventive agent according to claim 6, which is administered into the body "for a period of not less than one hour and not more than three days" before the pathogen enters the body.

9. A health food comprising an infectious disease preventive agent according to any one of claims 1 to 8.

10. A natural immunity activator, characterized in that it is an infectious disease preventive agent according to any one of claims 1 to 8.

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