as used herein , “ rapid desensitization ” refers to increasing the tolerance to one or a group of allergens more quickly than in the absence of treatment . as used herein , the term “ tolerance ” refers to the level of allergic response to a particular quantity of allergen . as used herein , the term “ antigen ” refers to a substance or substances alone or in combination that when introduced into the lymphatic system induces production of antibodies that bind to a fraction of the molecule or molecules . as used herein , the term “ allergen ” refers to a substance that could cause an allergic reaction in a patient . as used herein , the term “ allergic reaction ” refers to any untoward response to an allergen . as used herein , “ lymphatic system ” refers to the network of lymph containing vessels . as used herein , the term “ intradermal ” refers to residing within the dermal layer of skin or between the epidermal and dermal layers . as used herein , the term “ microneedle ” refers to a protrusion capable of penetrating the human epidermis in which its largest axis is less than three millimeters in length . as used herein , “ sharp microneedle ” refers to any microneedle that is capable of penetrating the human epidermis . as used herein , the term “ microparticle ” refers to any shaped particle that has at least one dimension less than one millimeter in size . as used herein , “ autologous transfusion ” refers to a whole or fractionated blood sample returned to the patient from whom it was taken by injection or intravenous infusion . as used herein , “ equivalent circle diameter ” refers to the diameter of a circle having the same cross - sectional area as the object being measured . as used herein , “ reservoir - type delivery system ” refers to formulations containing one or multiple antigen - rich and antigen - poor regions within each discrete clement of the delivery system . as used herein , “ matrix - type delivery system ” refers to formulations containing a random distribution of antigen within each discrete element of the delivery system . as used herein , the term “ biodegradable ” refers to a class of materials that undergo reductions in molecular weight upon introduction into a cell - containing environment . as used herein , the term “ bioadhesive ” refers to a class of materials that adheres to one or more biological substrates . as used herein , the term “ adjuvant ” refers to any agent that increases the immunological response to an antigen . as used herein , the term “ tip radius ” refers to the radius of a circle equivalent in cross - sectional area to the smallest aspect of a microstructure . as used herein , the term “ micropillar ” refers to any microstructure that is longer than it is wide and mechanically supports another microstructure . as used herein , “ enteric coating ” refers to any material that can protect an antigen from acidic degradation within the human stomach for a sufficiently long period of time such that at least ten percent of the antigen is delivered on average into the small intestines in an active form . as used herein , “ enteric protective polymer ” refers to any polymer that protects an antigen from acidic degradation within the human stomach for a sufficiently long period of time such that at least ten percent of the antigen is delivered on average into the small intestines in an active form . as used herein , the term “ encapsulant ” refers to any material that encapsulates another substance . as used herein , “ water soluble polymer ” refers to a class of polymers for which more than ten percent of the mass of the polymer enters solution in a volume of water or aqueous fluid . as used herein , “ ph sensitive polymer ” refers to a class of polymers that exhibit a ph dependent solubility profile . as used herein , “ enzymatically degradable polymer ” refers to a class of polymers containing regions that are chemically altered in the presence of one or more enzymes . as used herein , “ enzyme cleavable polymer ” refers to a class of polymers enzymatically degraded to yield a decrease in molecular weight . as used herein , the term “ peptide ” refers to at least two of any amino acid or amino acid derivative linked by a peptide bond . as used herein , the term “ phlebotomy ” refers to any means of obtaining a blood sample from a patient . as used herein , the term “ net charge altering agent ” refers to any compound that alters the net charge of a solution or suspension temporarily or permanently . clinically available allergens for inducing tolerance can be utilized . examples include peanut allergens , including , but not limited to peanut flour , arachis hypogaea 1 ( ara h 1 ), arachis hypogaea 1 ( ara h2 ); cat allergens , including but not limited to , felis domesticus allergen 1 - 4 ( fel d1 , fel d2 , fel d3 , fel d4 ), and cat iga ; house dust mite allergens , including , but not limited to , dermatophagoides pteronyssinus group 1 and 2 allergens ( der p1 and der p2 ); other house dust allergens , for example , house dust endotoxin ; pollen allergies , including , but not limited to bet v and bet v2 ; bee sting allergens , for example , phospholipase a2 ( pla2 ) one of the major bee venom allergen , wasp allergens ; cockroach calyx , penicillin , sulfonamides , salicylates , albumen , pollen , or their derivatives . u . s . pat . no . 8 , 182 , 805 to viskari , et al . discloses enteroviruses useful for decreasing allergic sensitization , identified by their effect on regulatory t - cells and / or th1 / th2 - balance and / or production of immunoregulatory cytokines such as il - 10 . in certain embodiments , the antigen is delivered in solution . in other embodiments , the antigen is delivered in suspension . in those embodiments in which the antigen is delivered in suspension , the antigen is formulated such that at least seventy percent of the population of microparticles , more preferably at least eighty percent of the population , and most preferably at lest ninety percent of the population of microspheres is small enough to phagocytosed by macrophages or dendritic cells , and too large to be endocytosed in quantities sufficient to cause an untoward allergic response by other cell types . in specific embodiments , the microparticles of antigen are in an appropriate size range for macrophage engulfinent , i . e ., the microparticles have a mean equivalent circle diameter of between one and ten , more preferably between two and nine , and most preferably between three and six microns . in certain embodiments , the mean diameter of the population of microparticles , in the case of irregularly shaped microparticles diameter refers to the diameter of a circle of equivalent cross - sectional area , is between two and nine microns , more preferably between three and eight microns , and most preferably between three and six microns . in certain embodiments , the at least seventy percent of , more preferably eighty percent of , and most preferably ninety percent of the diameter , or equivalent circle diameter , distribution within the population of administered antigen microspheres is within the range of one to ten microns , more preferably two to nine microns , and most preferably three to six microns . in some embodiments , microparticles of antigen encapsulated in a polymer are administered orally as a reservoir - type or matrix - type delivery system . the microparticles are fabricated by one or a combination of the following techniques including , but not limited to , emulsion solvent evaporation , double emulsion solvent evaporation , ionic gelation , coacervation , membrane emulsification , supercritical fluid microencapsulation , spray drying , and hot melt microencapsulation . in some embodiments the antigen is microencapsulated within a water - soluble polymer , or combination thereof , for example , polyvinyl alcohol , methylcellulose , hydroxypropyl methylcellulose , starch , dextran , albumin , and sodium alginate . in some embodiments , the antigen is microencapsulated in a ph - sensitive polymer that is stored at one ph and dissolves after entering the intradermal environment such as any of the following , or combination thereof , such as a polymer blend of acrylic acid and methacrylic acid , modified collagen , and modified crosslinked and un - crosslinked polyacrylic acids . in some embodiments , the antigen is encapsulated in a biodegradable polymer , or combination thereof , such as a polyhydroxyacid like polylactic acid , polyglycolic acid , or polylactic - co - glycolic acid , polyanhydride , polyorthoester , polyphosphate ester , polycaprolactone , and polyglycerol sebacate . in some embodiments , the antigen is encapsulated in a bioadhesive polymer , or combination thereof , such as polyfumaric - co - sebacic anhydride , chitosan , polyethylene maleic anhydride , catechol functional polymer , and lectin . in some embodiments , the antigen is encapsulated in an enzymatically cleavable polymer that is sensitive to degradation by macrophage lysozomal enzymes . in some embodiments , the enzymatically cleavable polymer contains peptide sequences cleaved by enzymes found in lysozomes , such as acid hydrolases and serine proteases . in some embodiments , the antigen is encapsulated in hydrogel polymers such as calcium alginate , chitosan and chitosan derivative complexes ( e . g . alginate - chitosan ), polyethylene glycol , and poly - 2 - hydroxyethyl methacrylate . in some embodiments , the antigen is microencapsulated in polyamino acids or combinations thereof such as polylysine , polyarginine , polyaspartate , and polyglutamate . in some embodiments , the polymer microparticles containing antigen are administered within an enterically coated capsule or tablet . in some embodiments , the polymer encapsulant is an enteric protective polymer such as one or a combination of the following including , but not limited to , eudragit ® l100 , eudragit ® l100 - 55 , eudragit 8100 , and modified collagen . in some embodiments , the antigen is microencapsulated within a water - soluble polymer . in some embodiments , the antigen is microencapsulated a ph - sensitive polymer that is stored at one ph and dissolves after entering the intradermal environment such as any combination of the following including , but not limited to polymer blends of acrylic acid and methacrylic acid , modified collagen , and modified crosslinked and un - crosslinked polyacrylic acids . in some embodiments , the antigen is encapsulated in a biodegradable polymer such as any combination of the following including , but not limited to , polylactic acid , polyglycolic acid , polylactic - co - glycolic acid , polyanhydrides , polyorthoesters , polyphosphate esters , polycaprolactone , and polyglycerol sebacate . in some embodiments , the antigen is encapsulated in a bioadhesive polymer such as any combination of the following including , but not limited to polyfumaric - co - sebacic anhydride , chitosan , polyethylene maleic anhydride , catechol functional polymers , and lectins . in some embodiments , the antigen is encapsulated in an enzymatically cleavable polymer that is sensitive to degradation by macrophage lysozomal enzymes . in some embodiments , the enzymatically cleavable polymer contains peptide sequences cleaved by enzymes found in lysozomes , such as any combination of the following including , but not limited to acid hydrolases and serine proteases . in some embodiments , release of the antigen from microcapsules can be accomplished using an encapsulating material that is specifically degraded by an enzyme or group of enzymes present within the phagocytic vesicles of a macrophage ( e . g . phagosomes and phagolysosomes ). in some embodiments , the antigen containing microparticles exhibit degradation kinetics tailored to release antigen once the macrophages leave the systemic circulation on average and return to the lymph after injection , in some embodiments microparticles release less than twenty five percent of the antigen within two days after injection , more preferably less than fifteen percent of the antigen within two days after injection , and most preferably less than ten percent of the antigen within two days after injection . in a specific embodiment , the encapsulating material can contain chitosan or a chitosan derivative ( e . g . alginate - chitosan ). chitosan and chitosan - derivatives are substrates for degradation by lysozyme within the macrophage cell body . lysozyme is present in highest concentrations within the phagolysosome , where the antigen would be released from microcapsules over time by degradation of the beta 1 , 4 - beta - linkages along the backbone of the chitosan or chitosan - derivative polysaccharide after phagocytosis of microcapsules . these macrophages subsequently release some of the free antigen within the lymph . in some embodiments , the antigen is encapsulated in hydrogel polymers such as any combination of the following including , but not limited to , calcium alginate , polyethylene glycol , and poly - 2 - hydroxyethyl methacrylate . in some embodiments , the antigen is microencapsulated in polyamino acids . in some embodiments , the antigen is encapsulated within more than one of the above polymers from a single or multiple groupings either physically mixed throughout each microparticle , or forming a core - shell morphology . in some embodiments the antigen is delivered along with an adjuvant excipients . in some embodiments , the adjuvant is a net charge altering agent such as , but not limited to one or a combination of charged amino acids including lysine , arginine , histidine , glutamate , and aspartate . uptake by macrophages can be encouraged by decorating the surface of the microcapsules with “ scavenger receptors ”, including , but not limited to , sr - ai and sr - aii or cd36 , involved in triggering phagocytosis of apoptotic cells . in another embodiment , functionalizing the microcapsule surface with an antibody , antibody derivative , antibody fragment , or aptamer to a macrophage surface protein , e . g . f4 / 80 , macrosialin ( fa - 11 ), sialoadhesin ( ser - 4 , 3d6 ), mannose receptors , or dectin - 1 , can be used to enhance phagocytotic uptake of microcapsules . in some embodiments the antigen is delivered along with an adjuvant . adjuvants include , but are not limited to , highly charged polymers such as ehitosan and polylysine . in some embodiments , a net charge altering agent is incorporated into the allergen suspension or solution such as , but not limited to one or a combination of , charged amino acids including lysine , arginine , histidine , glutamate , and aspartate , to encourage macrophage engulfment . individuals to be treated include any patient who suffers from sensitivity to an allergen . in specific embodiments patients may suffer from any or a combination of food allergies , environmental allergies , dust mite allergy , insect bite or sting allergies , and pet allergies . any one or a combination of the above treatment modalities are administered to a patient once a month for three months , more preferably twice a month for three to six months , and most preferably every fourteen days for a period of forty - two days . in some embodiments , the therapeutic regimen increases the immunoglobulin g levels within the patient , without significantly increasing the immunoglobulin e levels to induce allergen tolerance . in other embodiments , the compositions improve allergic desensitization as measured by decreased th2 response ( for example , th2 - type cytokines ) and / or increase th1 responses , for example , th1 - type cytokines . for example , the therapeutic regimen can reduce th2 and / or increase th1 responses . in these embodiments , the treatment regimen increases th1 - response , for example , by increasing interferon gamma and / or interleukin 10 and / or 12 production . gerada , et al ., lancet , 13 : 355 ( 9216 ): 1680 - 3 ( 2000 ). the treatment regimen can reduce th2 - type cytokines , for example interleukins 4 , 5 , and 13 , which have been associated with the promotion of ige and eosinophilic responses in atopy . berger , bmj , 321 : 424 . 1 ( 2000 ). pharmaceutically acceptable excipients are utilized as appropriate for the specific route of administration . for example , for injection , the formulation can be prepared in sterile saline , water or phosphate buffered saline . alternatively , hydrogels or dry particles may be injected , implanted or inserted with microneedles . in a preferred embodiment , antigen is delivered by high - pressure intradermal injection through hollow microneedles . the high pressure is necessary to create a pocket in the dermis . high - pressure intradermal drug delivery is known in the art and described for example , in gupta , et al ., biomateials , 32 : 6823 - 6831 ( 2011 ) and u . s . publication no . 20090157041 , the contents of which are hereby incorporated by reference . in some embodiments , one or a plurality of solid microneedles is used to deliver the antigen intradermally . in these embodiments , the antigen is formulated as a matrix - type or reservoir - type delivery system within a biodegradable polymer microstructure capable of penetrating the epidermis when supported by a biodegradable or non - degradable backing support layer . to achieve epidermal penetration at minimal force , the tip radius of the microstructure is less than or approximately equal to twenty - five , more preferably ten , and most preferably five microns . in these embodiments , the antigen is formulated as a matrix - type or reservoir - type delivery system within a biodegradable polymer microstructure capable of penetrating the epidermis when supported by a biodegradable or non - degradable backing support layer . to achieve epidermal penetration at minimal force , the tip radius of the microstructure is less than or approximately equal to twenty - five , more preferably ten , and most preferably five microns . in specific embodiments , one or a combination of the following techniques such as micromolding , wet etching , dry etching , and laser cutting is used to fabricate the antigen into a biodegradable or water - soluble polymer in a sharp microstructure . the sharp biodegradable polymer microstructures are supported either by the same or a similar material , or a non - degradable support such as an array of metallic micropillar supports . when the device is placed into the skin , it penetrates the epidermis and contacts or enters the dermis . each individual microneedle is approximately two and one half , more preferably less than one and one half , and most preferably less than one millimeter in length . in certain embodiments , a portion of or the entire biodegradable or water - soluble component of the microneedle array containing the antigen remains within the dermis after removal of the backing . to encourage phagocytosis by macrophages and dendritic cells , the biodegradable or water - soluble portions remaining in the dermis have an equivalent circle mean diameter of between one and ten , more preferably between two and nine , and most preferably between three and six microns . in specific embodiments , one or a combination of the following techniques such as micromolding , wet etching , dry etching , and laser cutting is used to fabricate the antigen into a biodegradable or water - soluble polymer in a sharp microstructure . the sharp biodegradable polymer microstructures are supported either by the same or a similar material , or a non - degradable support such as an array of metallic micropillar supports . when the device is placed into the skin , it penetrates the epidermis and contacts or enters the dermis . each individual microneedle is approximately two and one half , more preferably less than one and one half , and most preferably less than one millimeter in length . in certain embodiments , a portion of or the entire biodegradable or water - soluble component of the microneedle array containing the antigen remains within the dermis after removal of the backing . to encourage phagocytosis by macrophages and dendritic cells , the biodegradable or water - soluble portions remaining in the dermis have an equivalent circle mean diameter of between one and ten , more preferably between two and nine , and most preferably between three and six microns . in some embodiments , a net charge altering agent is incorporated into the allergen suspension or solution such as , but not limited to , one or a combination of charged amino acids , including lysine , arginine , histidine , glutamate , and aspartate , to encourage macrophage engulfment . in some embodiments , microparticles of antigen are delivered orally in an enterically coated capsule or tablet . in some embodiments , microparticles of antigen or polymer - encapsulated antigen are delivered to macrophages recruited from blood of the patient and then returned to the patient by injection or infusion . whole blood is obtained from the patient by phlebotomy . in some embodiments , the macrophages are separated from the whole blood by plating on tissue culture polystyrene or another material to which macrophages adhere . microparticles of antigen or polymer - encapsulated antigen are introduced in suspension to the macrophages in an appropriate size range for phagocytosis . after a period of time sufficient for the macrophages to engulf a therapeutic quantity as part of an allergic desensitization regimen , the autologous macrophages are re - introduced into the patient by injection or intravenous infusion . a proposed mechanism is that macrophages , dendritic cells in the skin , and peyer &# 39 ; s patches in the ileum will transport the particles into the lymph , where the t and b cells can begin antibody production . a kit for this purpose could include heparinized vacuum collection tubes containing antigen encapsulated in particulate form , a heat block for incubation at physiological temperature ( e . g . 37 ° c . ), a syringe - coupled filter to separate the small , freely suspended microcapsules remaining after incubation from the blood , and a resuspension buffer for injection of the cells back into the patient . in one embodiment , the heating element is a peltier heating and cooling device ; in another , the heating element is a resistive heater . in one embodiment , the separation of macrophages from freely suspended antigen microparticles occurs by size exclusion . in another embodiment , the separation of macrophages from freely suspended antigen microparticles occurs based on differences in density between the microparticles and the macrophages . the present invention will be further understood by the following non - limiting examples . low molecular weight chitosan greater than 75 percent deacetylated was dissolved in 1 percent aqueous glacial acetic acid to create a 5 milligram per milliliter aqueous chitosan solution . 9 milliliters of aqueous 1 % ovalbumin , 0 . 1 % sodium tripolyphosphate were added drop - wise into 18 milliliters of the 5 milligram per milliliter aqueous chitosan solution while vortexing . the resultant microparticles were sized by coulter particle size analysis as shown in fig1 . to isolate the population of microparticles that are approximately 2 microns in apparent diameter , the resultant population is filtered through a 1 micron filter to produce microparticles suitable for allergic desensitization to ovalbumin . modifications and variations of the present invention will be obvious from the foregoing description and are intended to come within the scope of the following claims .
methods and compositions for delivering antigens to the lymphatic system in doses that desensitize patients to future exposure to antigens have been developed . rapid desensitization is achieved by introducing small quantities of antigen into the lymphatic system . in preferred embodiments , the compositions are administered to yield therapeutically effective levels of antigen within the lymph , where macrophages reside in the greatest concentration , by intradermal administration , using for example , microneedles or micro articles , oral administration , using for example , enteric coated capsules or tablets , or autologous transfusion . in some embodiments , the methods and compositions for delivering antigens orally achieve uptake by the peyer &# 39 ; s patches of the small intestines .