g4 Meadow fescue

Allergens within Grass Pollens

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  • Latin name: Festuca elatior
  • Family: Poaceae (Graminae)
  • Subfamily: Pooideae
  • Tribe: Poeae
  • Common names: Meadow Fescue, English Bluegrass
  • Source material: Pollen
Synonyms: Festuca pratensis
 
Fescues are of two basic types, Meadow fescue (F.elatior, syn. F. pratensis) and Tall Fescue (F. arundinacea), with some confusion existing between their taxonomical designations. Tall Fescue is more persistent and more heavily yielding, so that it is now the dominant type. But their very close morphological similarity and habitat justify a simultaneous consideration of the plants as allergens.
 
A grass species producing pollen, which often induces hayfever, asthma and conjunctivitis in sensitised individuals.

Allergen Exposure

Geographical distribution
Fescue is a temperate-climate grass native to northern Europe and western Asia. It has been introduced and grows well in cool climates of the U.S., but is more common in Europe. It has been introduced in similar climates worldwide. It is a valuable pasture grass, used to a lesser extent for hay and as an all-purpose turf grass.
 
Tall Fescue is a robust, coarse-textured, bunch-type perennial. The erect stems can reach over a metre high. The main difference in Meadow Fescue is its much smaller height, typically less than half a metre. The 3 to 8 mm-wide and 10- to 50 cm-long leaf blades are upright, rolled when young, coarse on the upper surface and smooth underneath, succulent, and with rasplike margins and prominent veins. The leaves radiate from a central clump, and the sheaths of inferior leaves are purple-red.
 
The panicle-like inflorescence is up to 20 cm long. It spreads during flowering and contracts afterwards. The spikelets, green or faintly purple, are 3- to 11-flowered. The florets are hermaphrodite (have both male and female organs). The plant is wind-pollinated. Fescue flowering season is from May to July in the Northern Hemisphere, and from October to April in Australia. Fescue tends to be a solitary plant: it does not spread rapidly because of its lack of underground stolons or rhizomes.
 
Environment
Fescues grow best in open and damp sites such as roadsides, creeks, swampy verges and open paddocks, as well as in meadows and pastures. Tall Fescue's deep, extensive root system makes it suitable also for drought-prone sites.
 
Allergens
Meadow Fescue contains at least 24 antigens, of which 12 have been shown to bind Ige antibodies in sera from patients with well-established allergic rhinitis (1). A number of allergens have been isolated and characterised.
  • Fes p 1(2)
  • Fes e 1-B
  • Fes e 2-B
  • Fes p 4, a 60 kDa protein (3-4) 
A carbohydrate moiety appears to be involved in IgE binding to Fes p 4 (3).

Potential Cross-Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, as well as to a certain degree among members of the family Poaceae, and in particular within 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). 
 
This grass contains Group 1 allergens, to which more than 95% of patients allergic to grass pollen possess IgE antibodies. These are highly cross-reactive glycoproteins exclusively expressed in the pollen of many grasses (2, 7-8). Group 1 allergens are highly homologous, but not all of the antigenic epitopes are crossreactive (9). For example, Group 1 allergens from eight different clinically important grass pollens of the Pooideae (Rye grass, Canary grass, Meadow grass, Cocksfoot and Timothy), Chloridoideae (Bermuda grass) and Panicoideae (Johnson grass, Maize) were isolated, and IgE binding to an allergic human serum pool was conducted to determine the degree of antigenic and IgE-binding similarities. The highest IgE-binding similarity was observed between Cocksfoot and Rye grass (53%) and between Rye grass and Canary grass (43%). No IgE-binding similarity was observed between Maize and other grasses. The highest antigenic similarity was also observed between Rye grass and Cocksfoot grass (76%), and the lowest similarity between Maize (23%) and Bermuda (10%) (10). Highly homologous Group 1 allergens have been demonstrated between Pha a 1 from Canary grass, Lol p 1 from Rye grass pollen (a deduced amino acid sequence identity of 88.8%), Hol l 1 from Velvet grass pollen (88.1%), and  Phl p 1 from Timothy grass pollen (86.6%) (11). The major Timothy grass pollen allergen Phl p 1 also cross-reacts with most grass-, corn- and monocot-derived Group 1 allergens (12). Monoclonal antibodies of Cyn d 1 (Bermuda grass) recognised cross-reactive epitopes on proteins from eight other grasses including Rye grass, Timothy grass, Meadow grass and Johnson grass (13).
 
Meadow Fescue grass also contains a Group 4 allergen. Group 4 grass pollen allergens are glycoproteins with a molecular weight of 50 to 60 kDa, which are present in many grass species. Almost 75% of patients allergic to grass pollen display IgE reactivity to Group 4 allergens, which hence can be regarded as major grass pollen allergens (14). Inhibition studies of IgE antibody binding to Dac g 4 (Dactylis glomerata - Cocksfoot grass) with other 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 pratense (Meadow grass), Hordeum sativum (Barley), and Phleum pratense (Timothy grass) (15). Further, Phl p 4 homologes with similar molecular weights were detected in Dactylis glomerata (Cocksfoot grass), Festuca pratensis (Meadow Fescue), Holcus lanatus (Velvet grass), Poa pratensis (Meadow grass), and Lolium perenne (Rye grass). Group 4 homologes are present in the various grass extracts, but to different extents (3).
 
Immunological identity has been demonstrated between recombinant Dac g 2 (Cocksfoot grass) and Lol p 1and Lol p 2 (both from Rye grass). Similar cross-identity was observed with pollen extracts from three other grass species: Festuca rubra (Red Fescue), Phleum pratense (Timothy grass) and Anthoxanthum odoratum (Sweet Vernal grass). Recombinant Dac g 2 was recognized by species- and group-cross-reactive human IgE antibodies in 33% (4/12) of sera randomly selected from grass-sensitive individuals and in 67% (14/21) of sera from patients receiving grass pollen immunotherapy (16). As Festuca rubra is probably very cross-reactive with F. elatior, these findings by inference probably apply to the latter. This is supported by a study in which a monoclonal antibody against major Rye grass pollen that bound to the 28 to 30 kDa allergen showed binding to similar polypeptides in Meadow Fescue (17).

Clinical Experience

IgE mediated reactions
Meadow Fescue pollen is a common inducer of asthma, allergic rhinitis and allergic conjunctivitis (18).
 
In a Polish study, 22 patients between 13 and 53 years of age with seasonal allergic rhinitis were examined for specific IgE to 5 grass and 3 weed pollens. The most common sensitisation was to Meadow Fescue (F.pratensis), followed by Meadow grass (Poa pratensis), and Cocksfoot (Dactylis glomerata) (18).
 
In Norway, in 770 patients with seasonal and perennial nasal symptoms, pollens from Timothy, Meadow Foxtail, Meadow grass and Meadow Fescue were found to be very important causative factors (19).
 
Other reactions
Fescue grass is often infected with an endophyte, Acremonium coenophialum, which produces several classes of plant/fungal alkaloids. These are responsible for toxicosis problems in animals ingesting this grass, resulting in a syndrome called Fescue toxicosis (20). These pyrrolizidine alkaloids (in particular in Tall Fescue) may be excreted in cow's milk and pose a hazard to children ingesting milk (21).

Compiled by Dr Harris Steinman, harris@zingsolutions.com

References:

    1. Diener C, Skibbe K, Jager L. Identification of allergens in 5 grasses using crossed radioimmunoelectrophoresis (CRIE). [German] Allerg Immunol (Leipz) 1984;30(1):14-22 
    2. Hiller KM, Esch RE, Klapper DG. Mapping of an allergenically important determinant of grass group I allergens. J Allergy Clin Immunol 1997;100(3):335-40 
    3. Fahlbusch B, Muller WD, Rudeschko O, Jager L, Cromwell O, Fiebig H. Detection and quantification of group 4 allergens in grass pollen extracts using monoclonal antibodies. Clin Exp Allergy 1998;28(7):799-807 
    4. Gavrovic-Jankulovic M, Cirkovic T, Bukilica M, Fahlbusch B, Petrovic S, Jankov RM. Isolation and partial characterization of Fes p 4 allergen. J Investig Allergol Clin Immunol 2000;10(6):361-7 
    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. Grobe K, Becker WM, Schlaak M, Petersen A. Grass group I allergens (beta-expansins) are novel, papain-related proteinases. Eur J Biochem 1999;263(1):33-40 
    8. Schenk S, Breiteneder H, Susani M, Najafian N, Laffer S, Duchene M, Valenta R, Fischer G, Scheiner O, Kraft D, Ebner C. T cell epitopes of Phl p 1, major pollen allergen of timothy grass (Phleum pratense). Crossreactivity with group I allergens of different grasses. Adv Exp Med Biol 1996;409:141-6 
    9. Esch RE, Klapper DG. Cross-reactive and unique Group I antigenic determinants defined by monoclonal antibodies. J Allergy Clin Immunol 1987;78:489-95 
    10. Suphioglu C, Singh MB, Knox RB. Peptide mapping analysis of group I allergens of grass pollens. Int Arch Allergy Immunol 1993;102(2):144-51 
    11. Suphioglu C, Singh MB. Cloning, sequencing and expression in Escherichia coli of Pha a 1 and four isoforms of Pha a 5, the major allergens of canary grass pollen. Clin Exp Allergy 1995;25(9):853-65 
    12. Focke M, Mahler V, Ball T, Sperr WR, Majlesi Y, Valent P, Kraft D, Valenta R. Nonanaphylactic synthetic peptides derived from B cell epitopes of the major grass pollen allergen, Phl p 1, for allergy vaccination. FASEB J 2001;15(11):2042-4 
    13. Smith PM, Avjioglu A, Ward LR, Simpson RJ, Knox RB, Singh MB. Isolation and characterization of group-I isoallergens from Bermuda grass pollen. Int Arch Allergy Immunol 1994;104(1):57-64 
    14. Fischer S, Grote M, Fahlbusch B, Muller WD, Kraft D, Valenta R. Characterization of Phl p 4, a major timothy grass (Phleum pratense) pollen allergen. J Allergy Clin Immunol 1996;98(1):189-98 
    15. 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 
    16. Roberts AM, Van Ree R, Cardy SM, Bevan LJ, Walker MR. Recombinant pollen allergens from Dactylis glomerata: preliminary evidence that human IgE cross-reactivity between Dac g II and Lol p I/II is increased following grass pollen immunotherapy. Immunology 1992;76(3):389-96 
    17. Singh MB, Knox RB. Grass pollen allergens: antigenic relationships detected using monoclonal antibodies and dot blotting immunoassay. Int Arch Allergy Appl Immunol 1985;78(3):300-4 
    18. Silny W, Kuchta D, Siatecka D, Silny P. Antigen specific immunoglobulin E to grass and weed pollens in the plasma of patients with seasonal allergic rhinitis. [Polish] Otolaryngol Pol 1999;53(1):55-8 
    19. Holopainen E, Salo OP, Tarkiainen E, Malmberg H. The most important allergens in allergic rhinitis. Acta Otolaryngol Suppl 1979;360:16-8 
    20. Strickland JR, Oliver JW, Cross DL. Fescue toxicosis and its impact on animal agriculture. Vet Hum Toxicol 1993;35(5):454-64 
    21. Panter KE, James LF. Natural plant toxicants in milk: a review. J Anim Sci 1990;68(3):892-904

2002



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