g12 Cultivated rye

Allergens within Grass Pollens

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  • Latin name: Secale cereale
  • Family: Poaceae (Gramineae)
  • Subfamily: Pooideae
  • Tribe: Triticeae
  • Common names: Cultivated Rye, Rye
  • Source material: Pollen
Synonyms: Triticum cereale
 
There is a need to differentiate between Cultivated Rye grass pollen (Secale cereale) g12, Rye the foodstuff (Secale cereale) f5, Rye grass (Lolium perenne) g5, and Wild Rye grass (Elymus tricoides) g70.
 
A grass species producing pollen, which often induces hayfever, asthma and conjunctivitis in sensitised individuals.

Allergen Exposure

Geographical distribution
Probably native to the Mediterranean or southwestern Asia, but now widely cultivated in the temperate regions of the world, Rye can be grown in a wider range of environmental conditions than any other small grain. Winter Rye is the most winter-hardy of all cereals. Rye is cultivated in Central and Eastern Europe, Russia and North America, often where conditions are unfavorable for Wheat. Less than 50% of the Rye grown in the US is harvested for grain, with the remainder used as pasture, hay, or as a cover crop.
 
Rye is a hardy, tufted annual grass, 1 to 1.5 m tall, with a blue-green cast and an extensive root system. The leaves are 1.2cm or less broad, 7.5 to 15 cm long, smooth or slightly scabrous, and pointed; the leaf sheaths are long and loose. A 7 to 15 cm bushy spike is the flower head. The spikelets contain 2 fertile florets; the kernels are oblong, 0.8cm long, and light-brown.
 
It is in flower from May to July (in the Northern Hemisphere), giving rise to the well-known "smoke" when the Rye pollen is released in great masses. The seeds ripen from August to September. The flowers are hermaphrodite (have both male and female organs) and are pollinated by wind.
 
Environment
The plant grows in cultivated beds and requires full sunlight. It is also used as a pasturage grass, grazed in the fall or spring and then allowed to head-out and mature. It may be a weed in wheat fields, and may escape along roadsides and to waste places, but never becomes established outside cultivation.
 
Rye is widely cultivated for its grain and as valuable spring forage. A common cereal, Rye is used-especially in northern Europe-to make bread, cakes, etc. The seed can be sprouted and added to salads. Malt, a sweet substance produced by germinating the seed, is used as a sweetening agent and in making beer and whisky.
 
Unexpected exposure
The straw is used as a fuel or as a biomass in industry. It is quite strong and can also be used in archery targets, mushroom compost, bedding, thatching, for paper making, weaving mats and hats, and as a packing material for nursery stock, bricks and tiles. It is often dried for commercial flower arrangements.
 
Allergens
Cultivated Rye pollen contains more than 30 proteins that can be shown to be allergens in terms of their IgE binding in sera from Rye pollen-allergic individuals. Nine were determined to be major allergens. Using Western Blot, 17 allergens were isolated, 3 of them major allergens (1).
 
To date, only Sec c 5 has been characterised (2). Group 1, 4 and 5 allergens have been inferred from studies on cross-reactivity between grasses. Although other allergens have not yet been fully characterised, a 28 kDa allergen has been isolated (3), and allergens of 33 kDa, 48 kDa and 67 kDa detected (4).

Potential Cross-Reactivity

This pantemperate tribe Triticeae is notable for its cereal genera: Wheat, Barley and Rye. The close relation speaks in favour of cross-reactivity between Wild Rye grass g70, Cultivated Wheat g15, Cultivated Rye grass g12, Barley g201, and Couch grass (Agropyron repens) as well as Lymegrass (Elymus arenarius). An extensive cross-reactivity among the different individual species of the genus could be expected. There should be cross-reactivity with other members of the family Poaceae, particularly in the subfamily Pooideae (Rye grass (g5), Canary grass (g71), Meadow grass (g8), Timothy (g6), Cocksfoot (g3), Meadow Fescue (g4), Velvet (g13), Redtop (g9), Meadow Foxtail (g16), Wild Rye grass (g70)) (5-6).  
 
Phl p 1, a major allergen of Timothy grass, harbours multiple T-cell epitopes. Species-specific and cross-reacting T-cell epitopes were reported to exist among Group 1 grass allergens, which include Secale (7).
 
Inhibition studies of IgE antibody binding to Dac g 4 from Dactylis glomerata  (Cocksfoot grass) with pollen extracts confirmed the presence of cross-reactive allergens in Secale cereale (Cultivated Rye), Lolium perenne (Rye grass), Festuca elatior (Meadow Fescue), Holcus lanatus (Velvet grass), Bromus arvensis (Field Brome), Poa pratensis (Meadow grass), Hordeum sativum (Cultivated Barley), and Phleum pratense (Timothy) (8).
 
Natural pollen extracts from Anthoxanthum odoratum (Sweet Vernal grass), Avena sativa (Cultivated Oat), Cynodon dactylon (Bermuda grass), Lolium perenne (Rye grass), Phragmites australis (Common Reed), Poa pratensis (Meadow grass), Secale cereale (Cultivated Rye), Triticum sativum (Cultivated Wheat), and Zea mays (Maize/Corn) were characterized regarding their allergen contents by means of specific antibodies and by IgE immunoblot inhibition with recombinant allergens from Phl p 1, Phl p 2, Phl p 5, and Bet v 2 using sera 193 European, American, and Asian subjects. Immunologically detectable Group 5 and Group 2 allergens were found in all these species except for C. dactylon and Z. mays (9).
 
Pollen from 10 agricultural plant species was surveyed for the presence of proteins cross-reactive with Group 1, Group 4 and Group 9 allergens. Barley (Hordeum vulgare), Maize (Zea mays), Rye (Secale cerale), Triticale (Triticosecale cereale), Oat (Avena sativa), Canola (Brassica napus) and Sunflower (Helianthus annus) pollens contained numerous allergen-cognate proteins (10).
 
Cross-reactivity between Rye pollen and Rye seed has not been studied in detail. In a 1984 study, crossed line immunoelectrophoresis showed that some of the Rye pollen antigens were immunological partially identical with antigens of Wheat flour and Rye flour (11).

Clinical Experience

IgE mediated reactions
Cultivated Rye grass pollen can induce asthma, allergic rhinitis and allergic conjunctivitis (1-2).
 
In an early French study, Barley pollen and Rye pollen were reported to be important sensitising allergens in children with grass pollinosis, as determined by specific IgE studies (12).
 
The importance of grass pollen as a cause of hay fever in the South Plain of Hungary was studied. Of 642 patients with seasonal allergic rhinitis, 261 who experienced allergic rhinitis in May and June, when the daily pollen count of grass pollen was at its highest, were examined for specific IgE to various grasses. In this study 84% were positive to Poaceae grasses, and 63% to Secale (13).
 
In Saudi Arabia, Cultivated Rye pollen was shown to be one of the most abundant aeroallergens in sandstorm dust (14).
 
Other reactions
Antifreeze proteins, which are proteins that have the ability to retard ice crystal growth, have been identified as the most abundant apoplastic proteins in cold-acclimated Winter Rye leaves. All tests indicated that these antifreeze proteins are similar to members of three classes of pathogenesis-related proteins, namely endochitinases, endo-beta-1,3-glucanases, and thaumatin-like proteins (15).
 
Chitinases have also been isolated from Rye seed (16), but the relationship between these and the chitinases from Rye leaves has not yet been determined.

Rye infested with a fungus called ergot was responsible for several epidemics in medieval times.

Compiled by Dr Harris Steinman, harris@zingsolutions.com

References:

    1. Westphal W, Becker WM, Schlaak M. Analysis of rye pollen (Secale cereale) allergens using patients' IgE, immunoprint, Western Blot and monoclonal antibodies. Int Arch Allergy Appl Immunol 1988;86(1):69-75 
    2. van Ree R, Brewczynski PZ, Tan KY, Mulder-Willems HJ, et al. Grass pollen immunotherapy induces highly cross-reactive IgG antibodies to group V allergen from different grass species. Allergy 1995;50(3):281-3 
    3. Montero MT, Alonso E, Sainz T. Allergens from rye pollen (Secale cereale). II. Characterization and partial purification. Allergy 1992;47(1):26-9 
    4. Montero MT, Alonso E, Sainz T. Allergens from rye pollen (Secale cereale). I. Study of protein release by rye pollen during a 19-hour extraction process. Allergen identification. Allergy 1992;47(1):22-5 
    5. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09 
    6. Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000. 
    7. Schenk S, Breiteneder H, Susani M, Najafian N, Laffer S, Duchene M, Valenta R, Fischer G, Scheiner O, Kraft D, et al. T-cell epitopes of Phl p 1, major pollen allergen of timothy grass (Phleum pratense): evidence for crossreacting and non-crossreacting T-cell epitopes within grass group I allergens. J Allergy Clin Immunol 1995;96(6 Pt 1):986-96 
    8. Leduc-Brodard V, Inacio F, Jaquinod M, Forest E, David B, Peltre G. Characterization of Dac g 4, a major basic allergen from Dactylis glomerata pollen. J Allergy Clin Immunol 1996;98(6 Pt 1):1065-72 
    9. Niederberger V, Laffer S, Froschl R, Kraft D, Rumpold H, Kapiotis S, Valenta R, Spitzauer S. IgE antibodies to recombinant pollen allergens (Phl p 1, Phl p 2, Phl p 5, and Bet v 2) account for a high percentage of grass pollen-specific IgE. J Allergy Clin Immunol 1998;101(2 Pt 1):258-64 
    10. Astwood JD, Mohapatra SS, Ni H, Hill RD. Pollen allergen homologues in barley and other crop species. Clin Exp Allergy 1995;25(1):66-72 
    11. Renck B, Einarsson R. Crossed radioimmunoelectrophoretic analysis of cultivated rye (Secale cereale) pollen allergens. Int Arch Allergy Appl Immunol 1984;73(3):193-7 
    12. Lelong M, Thibaudon M, Thelliez PH. Is it necessary to test children having summer respiratory problems with cereal pollens? [French] Allerg Immunol (Paris) 1989;21(10):394-5 
    13. Kadocsa E, Juhasz M. Lawn grass (Poaceae) causing hayfever in the South Plain of Hungary. Results of aeropalinologic and allergologic studies 1989-95. [Hungarian] Orv Hetil 1997;138(14):851-4 
    14. Kwaasi AA, Parhar RS, al-Mohanna FA, Harfi HA, Collison KS, al-Sedairy ST. Aeroallergens and viable microbes in sandstorm dust. Potential triggers of allergic and nonallergic respiratory ailments. Allergy 1998;53(3):255-65 
    15. Hon WC, Griffith M, Mlynarz A, Kwok YC, Yang DS. Antifreeze proteins in winter rye are similar to pathogenesis-related proteins. Plant Physiol 1995;109(3):879-89 
    16. Yamagami T, Funatsu G. The complete amino acid sequence of chitinase-c from the seeds of rye (Secale cereal). Biosci Biotechnol Biochem 1993;57(11):1854-61

2002



Further Reading