Allergy information for: Maize, corn (Zea mays)

  • Name: Maize, corn
  • Scientific Name: Zea mays
  • Occurrence:
  • Allergy Information:

    Supplementary information on Corn (maize) Allergy

    <P>Corn (maize) is a plant belonging to the family of the grasses (Poaceae) and is cultivated globally being one of the most important cereal crops world-wide. Maize belongs to the genus Zea. Maize is not only an important human nutrient, but also a basic element of animal feed and a common ingredient for industrial products. Maize is found all over the world, mainly due to its easy processing, ready digestion, and cheaper cost than other cereals. It is also a versatile crop, allowing it to be grown across a range of agro-ecological zones. Today, the major maize production areas are located in temperate regions of the globe. The United States, China, Brazil, and Mexico account for 70% of the global production. In Europe, maize production is concentrated in the Mediterranean area (France, Italy and Spain) and in Eastern Europe (Romania and Hungary). According to FAO data, 589 million tons of maize was produced worldwide in 2000.</P><P>The maize seed is called the kernel, which contains starch, protein, oil and other nutritionally valuable substances such as carbohydrate, protein, iron, vitamin B, and minerals. Corn oil contains polyunsaturated fatty acid and vitamin E. Corn allergy is a so-called IgE-mediated food allergy. IgE (Immunoglobulin E) is the allergy antibody. Allergy to corn is caused by proteins in the kernels. Only one of these proteins has firmly been established as an allergen involved in corn allergy. This protein is called the lipid transfer protein (LTP). LTP has first been identified as an important allergen in fruits, but it is also present in nuts, various vegetables and in cereals. LTP is an extremely stable protein. It is resistant to food processing, including heating, but also to gastro-intestinal digestion. These properties make LTP a strong food allergen that can cause severe reactions. Other potential allergens in corn are storage proteins that have also been identified as allergens in other cereals like wheat. Some allergens in corn pollen are also present in the kernel. It is unlikely that these proteins play a role as allergens in food allergy to corn. </P><P><STRONG>Symptoms</STRONG></P><P>Corn allergy can lead to symptoms of the skin like atopic dermatitis or eczema and urticaria or nettle rash. It can also cause swelling of skin, lips or throat (angioedema), itching in mouth and throat, symptoms of the stomach/gut (diarrhoea, nausea, abdominal pain and vomiting), runny or stuffed nose and asthma, and in severe cases anaphylactic shock. All these symptoms have been observed in patients with allergy to corn LTP. Whether other allergens have a more limited pattern of symptoms is not known. </P><P><STRONG>Related foods (cross-reactions)</STRONG></P><P>Corn is related to other cereal grains like wheat, barley, oat, rye and rice. The only well-studied group of corn allergic patients is allergic to corn LTP. Of this group of 29 patients, around 1/3 (n=10) reported allergy to other cereals, the most commonly implicated being rice (8 times) and barley (5 times). This suggests that corn allergy caused by LTP is frequently accompanied by allergy to other cereals because they contain similar LTP. Such reactions based on similarity are called cross-reactions. </P><P><STRONG>Who, when, how long and how often?</STRONG></P><P>Very little is known about the occurrence of corn allergy. There are no studies that have investigated how often corn allergy occurs. The only clear risk factor for corn allergy so far identified is having IgE antibodies to LTP. This is most frequently seen in (young) adult patients with fruit allergy. The most common fruit implicated is peach. Almost all patients with allergy to corn linked to LTP also had peach allergy. Allergy to LTP seems to be life-long, although this has not really been studied.</P><P><STRONG>How much is too much?</STRONG></P><P&gt;For corn, it has not been established how little is enough to trigger an allergic reaction. For those patients that are allergic to corn on the basis of LTP, a minute amount (milligram range) might already be sufficient. Threshold studies are needed to confirm this.&lt;/P&gt;&lt;P&gt;&lt;STRONG&gt;Diagnosis&lt;/STRONG&gt;&lt;/P&gt;&lt;P&gt;Diagnosis of corn allergy starts with recording a clear clinical history to establish a link between allergic reactions and corn. Skin prick tests and measurement of specific IgE levels are used to support a history-based suspicion of IgE-mediated corn allergy. Corn shares similar allergens with other cereals but notably also with grass pollen. A positive skin test or serum IgE test for wheat can easily be based on cross-reactivity to grass pollen. Positive test results based on similarity between allergens from grass pollen and cereal proteins is a frequent cause of false-positive diagnoses. Corn also shares LTP with many plant-derived foods including fruits, nuts and vegetables. On the basis of similarity, IgE antibodies can cross-react between different LTPs. Although LTP is a potentially severe allergen, not every (cross-reactive) IgE response to corn LTP is of clinical relevance. To distinguish whether cross-reactions have clinical relevance, the only definitive method is a so-called double-blind placebo-controlled food challenge. In this procedure, increasing doses of corn are administered to the patient as well as placebo meals not containing corn. Both patient and doctor are unaware of the meals with and without corn. Effective blinding of the taste of corn is essential for such challenge procedures.&lt;/P&gt;&lt;P&gt;&lt;STRONG&gt;Where do I find corn?&lt;/STRONG&gt;&lt;/P&gt;&lt;P&gt;Whole kernels of corn are easily recognisable and are eaten separately, or in mixtures of (canned) vegetables, on pizza etc. Corn derived ingredients are however found in a broad variety of processed foods. About 15% of corn harvested is transformed into derivatives, like alcohol, oil, starch, corn syrup and dextrose. Whether corn-derived alcohol or corn oil contains enough protein to induce allergic reactions depends on the level of purity and the sensitivity of the individual patient. Corn oil is commonly used as salad or frying oil and in margarine. Cornstarch is primarily used to thicken and stabilize other ingredients in foods such as baking powder, prepared mixes, candies, baking goods, and puddings. Corn syrup is mainly used to replace sugar in confectionery, but also in bakery and dairy products, sweet beverages, candies, ketchup, pickles and other condiments. High fructose corn syrup (HFCS) and dextrose are used in confectionery, baked foods, table syrup, sweet beverages, ketchup, pickles and other condiments. The grits fractions are used in brewing processes, to produce corn flakes or are directly consumed boiled. Corn meal is a long shelf-life product used to produce a range of chemically leavened baked products, mainly bread; it is also used to make snack foods (corn chips and taco\Zs) and ready-to-eat breakfast cereals. In Italy it is used for making a dish called polenta.&lt;/P&gt;&lt;P&gt;&lt;STRONG&gt;Non-food products&lt;/STRONG&gt;&lt;/P&gt;&lt;P&gt;Corn oil is sometimes used in tooth paste. The likelihood of an allergic reaction depends on the level of purity (absence of protein) and the sensitivity of the patient. Corn syrup is often used as texturizer and carrying agent in cosmetics. Adhesives for envelopes, stamps and stickers might contain corn-starch. Medication can also be a source of hidden corn.&lt;/P&gt;&lt;P&gt;&lt;STRONG&gt;Avoidance&lt;/STRONG&gt;&lt;/P&gt;&lt;P&gt;For the treatment of food allergy, at present avoidance is the only solution. Since corn is used in many common food products, also as an 'invisible' ingredient, avoidance is difficult. Indications on food labels that point towards (possible) use of corn as an ingredient include baking powder, caramel colour, confectioners sugar, dextrin, dextrose, fructose, hominy, invert sugar, invert syrup, lactic acid, malto-dextrins, manitol, sorbitol, starch, vanilla extract and descriptions like vegetable broth and vegetable starch. &lt;/P&gt;&lt;P&gt;Currently, the presence of corn and corn-derived ingredients in pre-packaged foods does not require labelling under EU legislation. Allergic consumers should be aware of this and pay close attention to ingredient labelling when choosing products. &lt;/P&gt;
  • Other Information:
  • Taxonomic Information: NEWT http://www.ebi.ac.uk/newt/display?from=null&search=4577
  • Last modified: 18 October 2006

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      Clinical History

      • Number of Studies:6-10
      • Number of Patients:21-50
      • Symptoms:

        Pastorello et al. (2000) [465] reported 22 patients (mean age, 28.4 years) with oral allergy syndrome, OAS, (9/22), oedema of the glottis (10/22), urticaria (6/22), dyspnea (3/22), one patient showed asthma and one angioedema and gasterointesinal symptoms. However, there were 4 cases of anaphylatic shock and three of exercise-induced anaphylaxis.

        Pastorello et al. (2003) [759] reported symptoms from an additional 7 patients as laryngeal edema (4/7), urticaria(4/7), dyspnea (3/7), cough (2/7), angioedema(2/7), and single occurrences of OAS, rhinitis, asthma, diarrhoea and severe anaphylaxis .

        Pasini et al. (2002) [760] report symptoms from 6 patients as urticaria (5/6), OAS (2/6), gasterointesinal symptoms (2/6), and angioedema, rhinoconjunctivitis and asthma (1/6).

        Asero et al. (2002) [667] report 4 patients who experienced reactions after ingesting canned corn or salted maize snacks but tolerated "polenta" (a long-boiled cornbread dish).

        Figueredo et al. (1999) [796] report a patient with a severe anaphylatic reaction after eating a corn-made snack.

        Pauls & Cross (1998) [472] reported a case of food dependent exercise-induced anaphylaxis (FDEIA) to maize (corn) on eating taco (corn) chips, confirmed by challenge. Symptoms began with scalp and facial pruritis, then facial swelling and diffuse urticaria followed by a sensation of throat thickening and dyspnea. The individual was hypotensive with tachycardia. A year later the patient suffered symptoms on eating taco chips without exercise.

      Skin Prick Test

      • Number of Studies:1-5
      • Food/Type of allergen:

        Pasini et al. 2002 [760] used commercial extracts, a corn flour extract (in phosphate buffered saline) and the reduced soluble proteins (RSP) fraction, extracted with 50 mM Tris-HCl, pH 7.4 containing 20 mM dithiothreitol from the residue after salt extraction of cornflour.

        Figueredo et al. (1999) [796] used commercial extracts and extracted 2 g of the food in 10 ml phosphate buffered saline. After stirring for 60 min at room temperature, the extract was centrifuged at 5000 rpm for 20 min. The supernatant was collected, dialyzed in distilled water, and sterilized by filtration through a membrane of 0.22 µm pore diameter (Millipore, Bedford, MA, USA).

        Jones et al. 1995 [832] used extracts prepared by mixing 10 g. of cornflour with 30 ml of phosphate-buffered saline. Samples were mixed on a rocker for 4 hours at 4° C. Mixtures were centrifuged at 2500 X g for 10 minutes, then supernatants were collected and centrifuged at 17,000 X g for 10 minutes. Extracts were sterile-filtered, lyophilized, and stored at 4° C.

      • Protocol: (controls, definition of positive etc)

        Wheal diameters equal to or larger than 3mm were considered as positive in the absence of a reaction to the negative control (Pasini et al. 2002 [760]; Figueredo et al. 1999 [796]).

        A positive SPT response was defined as a wheal 3 mm larger than the negative (saline solution) control (Jones et al. 1995 [832]).

      • Number of Patients:

        Pasini et al. (2002) [760] report 16 patients selected following positive SPT.

        Figueredo et al. (1999) [796] report SPT on a single patient.

        Jones et al. (1995) [832] tested 98 patients by SPT.
      • Summary of Results:

        Pasini et al. (2002) [760] report positive SPT from 16 patients of whom 6 were allergic to corn and 10 tolerant. All 4/4 DBPCFC-positive patients tested reacted positively to the RSP fraction.

        Figueredo et al. (1999) [796] found that SPT with beer, barley, malt, wheat, maize, rye, rice, and oat flour were positive but only beer, barley and maize were clinically relevant in one patient.

        Jones et al. (1995) [832] report 24/98 positive SPT reactions to corn. Challenge of 17 of the SPT positive individuals gave 5 positive challenges.

      IgE assay (by RAST, CAP etc)

      • Number of Studies:0
      • Food/Type of allergen:

        Pasini et al. (2002) [760] extracted corn flour as described above (SPT) and also extracted cooked polenta by the same methods.

        Figueredo et al. (1999) [796] extracted 2 g of the food in 10 ml phosphate buffered saline. After stirring for 60 min at room temperature, the extract was centrifuged at 5000 rpm for 20 min. The supernatant was collected, dialyzed in distilled water, and sterilized by filtration through a membrane of 0.22 µm pore diameter (Millipore, Bedford, MA, USA).

      • IgE protocol:CAP
      • Number of Patients:

        Pasini et al. (2002) [760] used sera from 16 patients.

        Pastorello et al. (2000) [465] used sera from 22 patients.

      • Summary of Results:

        Pasini et al. (2002) [760] report positive CAP (2-4) results for 16 patients of whom 6 were allergic to corn and 10 tolerant.

        Pastorello et al. (2000) [465] found that all 22 individuals were CAP positive with the lowest having 0.362 and 0.438 kU/l of specific IgE. The other 20 were from 1.51 to 60.9 kU/l of specific IgE.

        Figueredo et al. (1999) [796] detected specific IgE antibodies in the patient's serum against malt (2.88 kU/l), barley (3.86 kU/l), corn (7.18 kU/l), wheat (3.05 kU/l), rye (3.17 kU/l), rice (1.5 kU/l), and oats (12.2 kU/l).

      Immunoblotting

      • Immunoblotting separation:

        Pasini et al. 2002 [760] separated proteins by 1D SDS-PAGE with 18% acrylamide separating gels. Samples were reduced with mecaptoethanol and heated for 5 min in a boiling water bath before separation.

        Pastorello et al. (2000) [465] separated proteins in a discontinuous buffer system with an SDS-PAGE gel (6% stacking gel and a 7.5%-20% separation gradient gel). Maize extract was diluted 1:2 in sample buffer.

        Figueredo et al. (1999) [796] used 1D SDS-PAGE with a 5% stacking gel and 15% separating gel. Samples were analysed without reduction.

      • Immunoblotting detection method:

        Pasini et al. 2002 [760] transfered proteins by semidry blotting onto nitrocellulose sheets. Blotted bands were visualized by soaking the membranes for a few minutes in Ponceau S (0.1% (w/v) in 3% (w/v) trichloroacetic acid) and marked with a pencil before destaining with water. Membranes were blocked with tris buffered saline (TBS) containing 0.05% (v/v) Tween 20 (TBS-T) and 5% (w/v) skim milk powder (M-TBS-T) for 2 h, and incubated overnight with single patient sera diluted in TBS-T. After washing five times with M-TBS-T, blots were incubated for 1 h with monoclonal antihuman IgE peroxidase-conjugate antibody (Sigma) diluted 1:5000 (v/v) in M-TBS-T. After four washes in M-TBS-T and one with TBS, bound IgE were visualized by chemiluminescence using the SuperSignal detection kit (Pierce).

        Pastorello et al. (2000) [465] electroblotted proteins either onto a nitrocellulose membrane (0.45 µm; Amersham, Buckinghamshire, UK) or onto a polyvinyl difluoride (PVDF) hydrophobic membrane (ProBlott, Applied Biosystem, Foster City, Calif) by using a trans-blot cell from BIO-RAD at 0.45 A and 100 V for 4 hours at 4°C. The unoccupied protein-binding sites were blocked by incubation with PBS (pH 7.4) with 0.5% (v/v) Tween-20. The nitrocellulose membrane was then cut into strips, which were incubated overnight with each patient’s serum and a negative serum as a control. IgE binding was detected by incubation with iodine 125–labeled anti-human IgE diluted 1:4 (v/v) in blocking solution and exposed on autoradiographic film (Hyperfilm, Amersham) in exposure cassettes at –70°C for 4 days.

        Figueredo et al. (1999) [796] transfered proteins electrophoretically to nitrocellulose membrane (BioRad, Richmond, CA, USA) in 0.025 mM Tris (pH 8.3), 0.192 mM glycine, 0.005% SDS and 20% methanol at 70 mA for 120 min. After transfer, the membrane was saturated for 60 min with 10 mM Tris buffered saline (TBS) containing 3% (w/v) bovine serum albumin (BSA). The membranes were then incubated with the patient's serum diluted 1:5 in 10 mM TBS containing 3% BSA and 1% (v/v) Tween 20 for 12-14 h. After four washes with 0.1% (v/v) Tween 20 in PBS, the membranes were incubated with antihuman IgE conjugated with peroxidase (The Binding Site, Birmingham, UK) for 3 h. The protein bands were developed by chemiluminiscence.

      • Immunoblotting results:

        Pastorello et al. (2000) [465] found that IgE from 19 (86%) of 22 sera analysed reacted with a 9-kDa band, 8 (36%) recognized a 16-kDa protein, and 5 (22.7%) reacted with higher MW bands, 25-85 kDa. The 9 and 16 kDa proteins were identified from the N-terminal sequences as a nsLTP and an alpha-amylase inhibitor respectively.

        Pasini et al. (2002) [760] report that immunoblotting experiments using sera of DBPCFC positive patients showed that the IgE-binding pattern of the proteins extracted by salt from the cooked sample was different from that obtained with the raw one, indicating that some physicochemical modifications of the allergens occurred during cooking of the corn flour. No IgE-binding was observed in the cooked sample corresponding to the 9 kDa protein band. However, IgE-binding to the band corresponding to the 50 kDa allergen was maintained in the cooked sample, showing that the physicochemical features and the IgE-binding ability of this protein were not affected by the heat treatment.

        Figueredo et al. (1999) [796] report a strong IgE binding band at 16-18 kDa and several above 30 kDa. The binding to higher molecular mass proteins but not to the 16-18 kDa band could be inhibited by malt extract.

      Oral provocation

      • Number of Studies:1-5
      • Food used and oral provocation vehicle:

        Polenta was made by boiling 25 g. fine milled corn flour for 30 minutes. 25 g. potato, 10g. carrot and turmezic and olive oil was cooked, mashed with a blender, added to polenta and mixed. The placebo used tapioca flour (Pasini et al. 2002 [760]).

        A treadmill exercise challenge was done 40 minutes after ingestion of 30 g. El Moleno brand taco chips (Pauls & Cross 1998 [472]).

        Up to 10 g. of the challenge substance was administered in graduated doses in a juice or “safe” food vehicle during a 90-minute period (Jones et al. 1995 [832]).

      • Blind:

        DBPCFC (Pasini et al. 2002) [760].

        Open (Pauls & Cross, 1998) [472].

        DBPCFC with negative checked by open challenge (Jones et al. 1995 [832]).

      • Number of Patients:

        Pasini et al. (2002) [760] tested 16 patients.

        Pauls & Cross (1998) [472] tested a 15 year old girl by open challenge with exercise.

        Jones et al. (1995) [832] tested 17 SPT positive patients.

      • Dose response:Not reported.
      • Symptoms:

        Pasini et al. (2002) [760] reported that 6/16 patients reacted to the challenge.

        Pauls & Cross (1998) [472] report that at maximal exercise, the patient had diffuse pruritis, light-headedness, and a sense of fullness in her nasal passages. She then progressed to mild left facial and periorbital swelling.

        Jones et al. (1995) [832] reported that 5/17 SPT positive patients reacted to the challenge.

      IgE cross-reactivity and Polysensitisation

      Asero et al. (2004) [990] report that allergy to peach nsLTP leads to skin reactivity to maize in 16/39 (41%) of patients.

      Enrique et al. (2002) [593] report that Platanus acerifolia pollinosis can lead to food allergy to maize.

      Lehrer et al. (1999) [1034] showed that in vitro IgE reactivity, determined by RAST on 123 sera from subjects with at least two of a history of allergy, a positive SPT or a positive RAST to maize, soybean, rice or peanut, was significantly correlated between rice and maize (r = 0.95) and soybean and maize (r=0.85) but not between peanut and maize (r=0.50).

      Figueredo et al. (1999) [796] report a patient with positive SPT with beer, barley, malt, wheat, maize, rye, rice, and oat flour and with clinically relevant allergy to beer, barley and maize. IgE binding to maize allergens was partially inhibited by barley malt extract.

      Other Clinical information

      Bock et al. 1978 [987] reported 4 children under 3 years who reacted to a maize challenge. David (1984) [988] reported a case of severe anaphylaxis to maize on resumption of consumption after an individual had been following an elimination diet to treat severe atopic dermatitis.

      Frisner et al. (2000) [332] reported the identification of alpha-zeins at 20 and 23 kDa as the only proteins above 2.5 kDa in an extensively hydrolysed infant formula. IgE binding to the formula at 18 and 20 kDa had been reported by Hoffman & Sampson (1997) [989].

      Reviews (0)

        References (15)

        • Jones SM, Magnolfi CF, Cooke SK, Sampson HA.
          Immunologic cross-reactivity among cereal grains and grasses in children with food hypersensitivity.
          J Allergy Clin Immunol. 96(3):341-351.. 1995
          PUBMEDID: 7560636
        • Enrique E, Cistero-Bahima A, Bartolome B, Alonso R, San Miguel-Moncin MM, Bartra J, Martinez A.
          Platanus acerifolia pollinosis and food allergy.
          Allergy 57(4):351-356. 2002
          PUBMEDID: 11906368
        • Pastorello EA, Pompei C, Pravettoni V, Farioli L, Calamari AM, Scibilia J, Robino AM, Conti A, Iametti S, Fortunato D, Bonomi S, Ortolani C.
          Lipid-transfer protein is the major maize allergen maintaining IgE-binding activity after cooking at 100 degrees C, as demonstrated in anaphylactic patients and patients with positive double-blind, placebo-controlled food challenge results.
          J Allergy Clin Immunol. 112(4):775-83.. 2003
          PUBMEDID: 14564361
        • Pastorello EA, Farioli L, Pravettoni V, Ispano M, Scibola E, Trambaioli C, Giuffrida MG, Ansaloni R, Godovac-Zimmermann J, Conti A, Fortunato D, Ortoloni C.
          The major maize allergen, which is responsible for food-induced allergic reactions, is a lipid transfer protein.
          Allergy Clin Immunol 106:744-751.. 2000
          PUBMEDID: 11031346
        • Frisner H, Rosendal A, Barkholt V.
          Identification of immunogenic maize proteins in a casein hydrolysate formula.
          Pediatr Allergy Immunol 11:106-110.. 2000
          PUBMEDID: 10893013
        • Pauls JD, Cross D.
          Food-dependent exercise-induced anaphylaxis to corn.
          J Allergy Clin Imunol. 101:853-54.. 1998
          PUBMEDID: 9648717
        • Pasini G, Simonato B, Curioni A, Vincenzi S, Cristaudo A, Santucci B, Peruffo AD, Giannattasio M.
          IgE-mediated allergy to corn: a 50 kDa protein, belonging to the Reduced Soluble Proteins, is a major allergen.
          Allergy. 57(2):98-106.. 2002
          PUBMEDID: 11929411
        • Asero R, Mistrello G, Roncarolo D, Amato S, Caldironi G, Barocci F, van Ree R.
          Immunological cross-reactivity between lipid transfer proteins from botanically unrelated plant-derived foods: a clinical study.
          Allergy 57(10):900-906. 2002
          PUBMEDID: 12269935
        • Bock SA, Lee WY, Remigio LK, May CD.
          Studies of hypersensitivity reactions to foods in infants and children.
          J Allergy Clin Immunol. 62(6):327-334.. 1978
          PUBMEDID: 81844
        • Asero R, Mistrello G, Roncarolo D, Amato S.
          Relationship between peach lipid transfer protein specific IgE levels and hypersensitivity to non-Rosaceae vegetable foods in patients allergic to lipid transfer protein.
          Ann Allergy Asthma Immunol. 92(2):268-272.. 2004
          PUBMEDID: 14989398
        • David TJ.
          Anaphylactic shock during elimination diets for severe atopic eczema.
          Arch Dis Child. 59(10):983-986.. 1984
          PUBMEDID: 6541895
        • Hoffman KM, Sampson HA.
          Serum specific-IgE antibodies to peptides detected in a casein hydrolysate formula.
          Pediatr Allergy Immunol. 8(4):185-189.. 1997
          PUBMEDID: 9553983
        • Lehrer SB, Reese G, Malo JL, Lahoud C, Leong-Kee S, Goldberg B, Carle T, Ebisawa M.
          Corn allergens: IgE antibody reactivity and cross-reactivity with rice, soy, and peanut.
          Int Arch Allergy Immunol. 118(2-4):298-299.. 1999
          PUBMEDID: 10224418
        • Figueredo E, Quirce S, del Amo A, Cuesta J, Arrieta I, Lahoz C, Sastre J.
          Beer-induced anaphylaxis: identification of allergens.
          Allergy 54(6):630-634.. 1999
          PUBMEDID: 10435480
        • Tanaka LG, El-Dahr JM, Lehrer SB.
          Double-blind, placebo-controlled corn challenge resulting in anaphylaxis.
          J Allergy Clin Immunol. 107(4):744. 2001
          PUBMEDID: 11295671

        Biochemical Information for 50 kDa allergen

        • Allergen Name:50 kDa allergen
        • Alternatve Allergen Names:Reduced Soluble Proteins
        • Allergen Designation:Major
        • Protein Family:Not known
        • Sequence Known?:No
        • Allergen accession No.s:N/A
        • 3D Structure Accession No.:N/A
        • Calculated Masses:N/A
        • Experimental Masses:50 kDa
        • Oligomeric Masses:Not known
        • Allergen epitopes:Not Known
        • Allergen stability:
          Process, chemical, enzymatic:          The electrophoretic patterns of the RSP fractions from raw and cooked corn were similar with a strong 50 kDa protein band and the IgE binding to the 50 kDa band survives cooking. IgE immunoblotting showed that the 50 kDa allergen was stable during 30 min of pepsin degradation and disappeared only after more than 90 minutes of pancreatin treatment (Pasini et al. 2002) [760].
        • Nature of main cross-reacting proteins:Not known
        • Allergen properties & biological function:Not known.
        • Allergen purification:

          Pasini et al. 2002 [760] extracted corn flour with 0.5 M NaCl (repeated 3 times) and with water. The salt extracted residue with 50 ml of 50 mM Tris-HCl, pH 7.4 containing 20 mM dithiothreitol by the method of Vitale et al. (1982) [993]. The extract is called the "Reduced Soluble Protein fraction" and contains proteins with several masses.

        • Other biochemical information:The "Reduced Soluble Proteins" are often considered equivalent to the gamma-zeins with masses of 16 and 27 kDa. The 50 kDa allergen of Pasini et al. 2002) [760] is purified with the reduced soluble proteins but may not be a zein.

        References (2)

        • Pasini G, Simonato B, Curioni A, Vincenzi S, Cristaudo A, Santucci B, Peruffo AD, Giannattasio M.
          IgE-mediated allergy to corn: a 50 kDa protein, belonging to the Reduced Soluble Proteins, is a major allergen.
          Allergy. 57(2):98-106.. 2002
          PUBMEDID: 11929411
        • Vitale A, Smaniotto E, Longhi R, Galante E.
          Reduced soluble proteins associated with maize endosperm protein bodies.
          J Exp Bot 33:439-448.. 1982
          PUBMEDID:

        Biochemical Information for Alpha-Zeins

        • Allergen Name:Alpha-Zeins
        • Alternatve Allergen Names:
        • Allergen Designation:Minor
        • Protein Family:Alpha-prolamins; http://www.sanger.ac.uk/cgi-bin/Pfam/getacc?PF01559
        • Sequence Known?:Yes
        • Allergen accession No.s:

          ZMZM19 : Swissprot: http://ca.expasy.org/cgi-bin/niceprot.pl?P04706

          ZIZMA2 : Swissprot: http://ca.expasy.org/cgi-bin/niceprot.pl?P06674

          T01326 : Swissprot:http://ca.expasy.org/cgi-bin/niceprot.pl?O48969

        • 3D Structure Accession No.:Not determined
        • Calculated Masses:19, 23 kDa
        • Experimental Masses:20 and 23 kDa
        • Oligomeric Masses:

        • Allergen epitopes:Not known
        • Allergen stability:
          Process, chemical, enzymatic:          The prolamin allergens of maize appear to be stable to cooking (in corn chips) and the alpha-zeins may also resist proteolysis (Frisner et al. 2000 [332]; Pasini et al. 2002 [760]).
        • Nature of main cross-reacting proteins:Not known
        • Allergen properties & biological function:

          Zeins are maize seed storage proteins and are prolamins. Separation of the prolamins by SDS-PAGE shows five major groups, Mr 27,000 and 16,000 gamma-zeins, Mr 22,00 and 19,000 alpha-zeins, Mr 15,000 beta-zeins and Mr 10,000 delta-zeins. The zeins are structurally distinct from the prolamins of wheat, barley, oats and rice, but similar to the prolamins of sorghum and millets in containing 40-50% of alpha-helix. Some studies have also reported significant beta-sheet structure. The alpha-zeins are formed from 9 or 10 repeats of about 20 amino acids and have an elongated structure in solution (Garratt et al. 1993 [1027]; Tatham et al. 1993 [1028]; Matsushima et al. 1997 [1029]; Forato et al. 2004 [1030]) which may form a tightly packed protein body.

        • Allergen purification:

          Cornflour was extracted with acetone and hexane to remove lipid and dried. A 70% (v/v) aqueous methanol extract was then made and decolourised over activated charcoal. After filtration, the extract was dialysed and lyophilised. The zeins were separated using gel-filtration on Sephacryl S-300 in 70% (v/v) aqueous ethanol. The Z19/Z22 fraction was dialysed and lyophilised (Tatham et al. 1993 [1028]).

          Forato et al. (2004) [1030] extracted pure Z19 from the BR451 maize variety which does not express the Z22 zeins.

        • Other biochemical information:

          The accession codes and sequences are only representative. Over 20 sequences are deposited with 83% or higher identity.

          Frisner et al. (2000) [332] reported the identification of alpha-zeins at 20 and 23 kDa as the only proteins above 2.5 kDa in an extensively hydrolysed infant formula. IgE binding to the formula at 18 and 20 kDa had been reported by Hoffman & Sampson (1997) [989].
          However, Pasini et al. (2002) [760] did not observe IgE binding to alpha-zeins in their food allergic patients.

        References (9)

        • Marks M.D., Lindell J.S. and Larkins B.A.
          Nucleotide sequence analysis of zein mRNAs from maize endosperm.
          J. Biol. Chem. 260;16451-16459 .. 1985
          PUBMEDID: 2999157
        • Coleman GE, Larkins BA
          The prolamins of maize.
          In: Seed Proteins (Shewry PR & Casey R eds) Kluwer pp109-139.. 1999
          PUBMEDID:
        • Frisner H, Rosendal A, Barkholt V.
          Identification of immunogenic maize proteins in a casein hydrolysate formula.
          Pediatr Allergy Immunol 11:106-110.. 2000
          PUBMEDID: 10893013
        • Hoffman KM, Sampson HA.
          Serum specific-IgE antibodies to peptides detected in a casein hydrolysate formula.
          Pediatr Allergy Immunol. 8(4):185-189.. 1997
          PUBMEDID: 9553983
        • Garratt R, Oliva G, Caracelli I, Leite A, Arruda P.
          Studies of the zein-like alpha-prolamins based on an analysis of amino acid sequences: implications for their evolution and three-dimensional structure.
          Proteins 15(1):88-99.. 1993
          PUBMEDID: 8451243
        • Tatham AS, Field JM, Morris VJ, I'Anson KJ, Cardle L, Dufton MJ, Shewry PR.
          Solution conformational analysis of the alpha-zein proteins of maize.
          J Biol Chem. 268(35):26253-26259.. 1993
          PUBMEDID: 8253747
        • Matsushima N, Danno G, Takezawa H, Izumi Y.
          Three-dimensional structure of maize alpha-zein proteins studied by small-angle X-ray scattering.
          Biochim Biophys Acta 1339(1):14-22.. 1997
          PUBMEDID: 9165095
        • Forato LA, Doriguetto AC, Fischer H, Mascarenhas YP, Craievich AF, Colnago LA.
          Conformation of the Z19 prolamin by FTIR, NMR, and SAXS.
          J Agric Food Chem. 52(8):2382-2385.. 2004
          PUBMEDID: 15080650
        • Pasini G, Simonato B, Curioni A, Vincenzi S, Cristaudo A, Santucci B, Peruffo AD, Giannattasio M.
          IgE-mediated allergy to corn: a 50 kDa protein, belonging to the Reduced Soluble Proteins, is a major allergen.
          Allergy. 57(2):98-106.. 2002
          PUBMEDID: 11929411

        Biochemical Information for Trypsin inhibitor

        • Allergen Name:Trypsin inhibitor
        • Alternatve Allergen Names:Activated Hageman factor (XIIA)
        • Allergen Designation:Minor
        • Protein Family:PFAM PF00234; tryp_alpha_amyl; 2S albumin subfamily.
        • Sequence Known?:Yes
        • Allergen accession No.s:http://us.expasy.org/cgi-bin/niceprot.pl?P01088
        • 3D Structure Accession No.:

          1BEA
          1BFA

        • Calculated Masses:16302 (precursor)
          11893.74 (mature)
        • Experimental Masses:16-kDa
        • Oligomeric Masses:Monomer
        • Allergen epitopes:Not known
        • Allergen stability:
          Process, chemical, enzymatic:

          Because of the 5 disulphide bridges, the inhibitor is likely to be stable to thermal treatment and proteolysis unless reduced.

        • Nature of main cross-reacting proteins:None known
        • Allergen properties & biological function:It is a potent inhibitor of trypsin and may have a protective function against pests and pathogens in the plant.
        • Allergen purification:Hazegh-Azam et al (1998) [995] report the purification of the recombinant trypsin inhibitor expressed in E. coli in two form (one with an N-terminal tag) and show that these have a similar fold to the protein purified from maize by Lei & Reeck (1986) [996] using a trypsin-agarose column with elution by 1.0 M glycine buffer, pH 2.1, and reversed-phase HPLC.
        • Other biochemical information:Pastorello et al. (2000) [465] identified the trypsin inhibitor from the N-terminal sequence of a 16 kDa protein: Ser-Ala-Gly-Thr-Ser-Cys-Val-Pro-Gly-Trp-Ala-Ile-Pro-His-Asn-Pro. The 16 kDa protein was recognized by sera from 8 of 22 patients (36%). Homologues from Triticeae (eg. wheat) have been identified as allergens in baker's asthma.

        References (4)

        • Pastorello EA, Farioli L, Pravettoni V, Ispano M, Scibola E, Trambaioli C, Giuffrida MG, Ansaloni R, Godovac-Zimmermann J, Conti A, Fortunato D, Ortoloni C.
          The major maize allergen, which is responsible for food-induced allergic reactions, is a lipid transfer protein.
          Allergy Clin Immunol 106:744-751.. 2000
          PUBMEDID: 11031346
        • Behnke CA, Yee VC, Trong IL, Pedersen LC, Stenkamp RE, Kim SS, Reeck GR, Teller DC.
          Structural determinants of the bifunctional corn Hageman factor inhibitor: x-ray crystal structure at 1.95 A resolution.
          Biochemistry 37(44):15277-15288.. 1998
          PUBMEDID: 9799488
        • Hazegh-Azam M, Kim SS, Masoud S, Andersson L, White F, Johnson L, Muthukrishnan S, Reeck G.
          The corn inhibitor of activated Hageman factor: purification and properties of two recombinant forms of the protein.
          Protein Expr Purif. 13(2):143-149.. 1998
          PUBMEDID: 9675055
        • Lei MG, Reeck GR.
          Combined use of trypsin-agarose affinity chromatography and reversed-phase high-performance liquid chromatography for the purification of single-chain protease inhibitor from corn seeds.
          J Chromatogr. 363(2):315-321.. 1986
          PUBMEDID: 3771690

        Biochemical Information for Zea m 14

        • Allergen Name:Zea m 14
        • Alternatve Allergen Names:non-specific lipid tranfer protein, ns-LTP
        • Allergen Designation:Major
        • Protein Family:non specific lipid transfer proteins (LTPs) Pfam PF00234
        • Sequence Known?:Yes
        • Allergen accession No.s:

          P19656:Swissprot: http://ca.expasy.org/cgi-bin/niceprot.pl?P19656

        • 3D Structure Accession No.:1MZL, 1MZM, 1AFH, 1FK0, 1FK1, 1FK2, 1FK3, 1FK4, 1FK5, 1FK6, 1FK7
        • Calculated Masses:9054 Daltons
        • Experimental Masses:9 kDa
        • Oligomeric Masses:monomer
        • Allergen epitopes:Not known
        • Allergen stability:
          Process, chemical, enzymatic:          Allergenicity survives cooking at 100 degrees C. However, heating leads to denaturation of the protein at approximately 83.5 degrees (Pastorello et al. 2003 [759]).
        • Nature of main cross-reacting proteins:The IgE to maize LTP has been shown to be cross react with rice and peach LTPs but not with those from wheat or barley.
        • Allergen properties & biological function:LTPs may act as anti-fungal and anti-bacterial defence proteins.
        • Allergen purification:Shin et al. (1994) [997] modified the method of Douady et al. (1982) [998] using maize seeds germinated in the dark for 3 days, roots were discarded and the seedlings ground with extraction buffer (25 mM sodium phosphate at pH7.0 with 3 mM EDTA, 3 mM L-cysteine, 8 mM mercaptoethanol). The extract was centrifuged at 8500g for 50 minutes and the supernatant heated to 70° C for 10 minutes. after standing for 24 hours at 4° C, the sediment was removed by centrifuging at 15,600g for 10 minutes. The supernatant was loaded onto a CM-cellulose column in 25 mM sodium phosphate at pH7.0 and eluted by a gradient of 0-0.5M NaCl. Fractions with nsLTP were concentrated and loaded on Sepadex G-50. A second CM-cellulose column was eluted with a 50mM-300 mM NaCl gradient and nsLTP was dialysed and used.
        • Other biochemical information:

        References (7)

        • Pastorello EA, Pompei C, Pravettoni V, Farioli L, Calamari AM, Scibilia J, Robino AM, Conti A, Iametti S, Fortunato D, Bonomi S, Ortolani C.
          Lipid-transfer protein is the major maize allergen maintaining IgE-binding activity after cooking at 100 degrees C, as demonstrated in anaphylactic patients and patients with positive double-blind, placebo-controlled food challenge results.
          J Allergy Clin Immunol. 112(4):775-83.. 2003
          PUBMEDID: 14564361
        • Pastorello EA, Farioli L, Pravettoni V, Ispano M, Scibola E, Trambaioli C, Giuffrida MG, Ansaloni R, Godovac-Zimmermann J, Conti A, Fortunato D, Ortoloni C.
          The major maize allergen, which is responsible for food-induced allergic reactions, is a lipid transfer protein.
          Allergy Clin Immunol 106:744-751.. 2000
          PUBMEDID: 11031346
        • Gomar J, Petit MC, Sodano P, Sy D, Marion D, Kader JC, Vovelle F, Ptak M
          Solution structure and lipid binding of a nonspecific lipid transfer protein extracted from maize seeds.
          Protein Sci. 5: 565-577.. 1996
          PUBMEDID: 8845747
        • Petit, M.C., Sodano, P., Marion, D. and Ptak, M.
          Two-dimensional 1H-NMR studies of maize lipid-transfer protein. Sequence-specific assignment and secondary structure.
          Eur. J. Biochem. 222: 1047-1054.. 1994
          PUBMEDID: 8026483
        • Tchang F, This P, Stiefel V, Arondel V, Morch M-D, Pages M, Puigdomenech P, Grellet F, Delseny M, Bouillon P, Huet J-C, Guerbette F, Beauvais-Cante F, Duranton H, Pernollet J-C, Kader J
          Phospholipid transfer protein: full-length cDNA and amino acid sequence in maize. Amino acid sequence homologies between plant phospholipid transfer proteins.
          J. Biol. Chem. 263: 16849-16855.. 1988
          PUBMEDID: 3182817
        • Douady D, Grosbois M, Guerbette F, Kader JC
          Proteins and the intracellular exchange of lipids. 9. Purification of a basic phospholipid transfer protein from maize seedlings.
          Biochim. Biophy. Acta 710 (2): 143-153. 1982
          PUBMEDID:
        • Shin DH, Hwang KY, Kim KK, Kim S, Sweet RM, Suh SW.
          Crystallization and preliminary X-ray crystallographic analysis of phospholipid transfer protein from maize seedlings.
          Proteins 19(1):80-83.. 1994
          PUBMEDID: 8066090