g71 Canary grass

Print Tell a friend

• Latin name: Phalaris arundinacea
• Family: Poaceae (Gramineae)
• Subfamily: Pooideae
• Tribe: Aveneae
• Common names: Reed Canary grass, Reed Canary grass, Ribbon grass, Variegated grass
• Source material: Pollen

• Phalaris canariensis - Canary grass, Canarygrass (UK), Canary Seed, Canaryseed, Canary Bird Seed;
   
• Phalaris aquatica - Bulbous Canary grass, Harding grass, Hardinggrass (Canada), Toowoomba Canary grass (Australia);
   
• Phalaris. coerulescens - Blue Canary grass.

• Pha a 1, a 34 kDa protein, a major allergen (1)
• Pha a 5, a major allergen existing in four isoforms (1)

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, in particular grasses belonging to the Pooideae sub-family (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)) (2-3).

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 (4-6). Group 1 allergens are highly homologous, but not all of the antigenic epitopes are crossreactive (7). 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%) (8). 

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%) (9). The major Timothy grass pollen allergen Phl p 1 also cross-reacts with most grass-, Corn- and monocot-derived Group 1 allergens (10).  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 (11).

Pha a 1 from Bulbous Canary grass (P. aquatica) has been shown to have common allergenic components with other grasses. In a separate study, IgE binding of Pha a 1, Lol p 1 (Ryegrass), and Cyn d 1 (Bermuda grass) was investigated in 24 sera of Bulbous Canary grass-allergic individuals and found to occur in 19/24, 18/24, and 9/24, respectively. IgE binding to all three major allergens, or to both Pha a 1 and Lol p 1, occurred in 8/24 sera. The findings suggested that while the N-terminal sequence of Pha a 1 was identical to Lol p 1, there may be specific allergenic epitopes exclusive to this allergen that are important for allergenicity in southern Australia(12). As P. aquatica and P. arundinacea are closely related, this may apply to the latter grass pollen as well.

Canary grass pollen contains a Group 5 allergen. Almost 90% of grass pollen-allergic patients are sensitised against Group 5 grass pollen allergens. A monoclonal human IgE antibody has been shown to cross-react with Group 5A isoallergens from several grass and Corn species (13). Polymorphic forms of Pha a 5 from Canary grass have been shown to share significant sequence identity with other group 5 allergens from Rye-grass, Timothy and Meadow grass pollens (1). Group 5 allergens have been detected in Phleum pratense, Lolium perenne (Rye grass), Poa pratense (Meadow grass) and Dactylis glomerata (Cocksfoot) extracts. The major components in these fractions were found to be 25-28 kDa proteins, and IgE binding to these components was confirmed using a pool of grass-allergic sera (14).

Sequence comparisons showed that the Hor v 9 cDNA clones (Barley pollen) were also homologous to Group 5 allergens of Timothy grass (Phleum pratense) pollen and Bulbous Canary grass (Phalaris aquatica) pollen, and to the Group 9 allergen of Ryegrass (Lolium perenne) pollen (15). 

Clinical Experience 

IgE mediated reactions
Canary grass pollen often induces asthma, allergic rhinitis and allergic conjunctivitis (13).

Canary grass pollen has been found in aeroallergen studies in the Western Cape, South Africa (16).

Specific IgE measurements in sera from subjects sensitized to wheat and rye flour indicated that there is significant reaction with seed extracts of 12 cereals (Wheat, Durum Wheat, Triticale, Cereal Rye, Barley, Rye grass, Oats, Canary grass, Rice, Maize, Sorghum and Johnson grass) (17).

Compiled by Dr Harris Steinman, harris@zingsolutions.com

References:

1. Suphioglu,C., Singh, M.B. 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;25:853-865 
   
2. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09 
   
3. Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000. 
   
4. 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 
   
5. 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 
   
6. Hiller KM, Esch RE, Klapper DG. Mapping of an allergenically important determinant of grass group I allergens. J Allergy Clin Immunol 1997 Sep;100(3):335-40 
   
7. Esch RE, Klapper DG. Cross-reactive and unique Group I antigenic determinants defined by monoclonal antibodies. J Allergy Clin Immunol 1987;78:489-95 
   
8. 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 
   
9. 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 
   
10. 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 
    
11. 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 
    
12. Suphioglu C, Singh MB, Simpson RJ, Ward LD, Knox RB. Identification of canary grass (Phalaris aquatica) pollen allergens by immunoblotting: IgE and IgG antibody-binding studies. Allergy 1993;48(4):273-81 
    
13. Flicker S, Vrtala S, Steinberger P, Vangelista L, Bufe A, Petersen A, Ghannadan M, Sperr WR, Valent P, Norderhaug L, Bohle B, Stockinger H, Suphioglu C, Ong EK, Kraft D, Valenta R. A human monoclonal IgE antibody defines a highly allergenic fragment of the major timothy grass pollen allergen, Phl p 5: molecular, immunological, and structural characterization of the epitope-containing domain. J Immunol 2000;165(7):3849-59 
    
14. Klysner S, Welinder KG, Lowenstein H, Matthiesen F. Group V allergens in grass pollens: IV. Similarities in amino acid compositions and NH2-terminal sequences of the group V allergens from Lolium perenne, Poa pratensis and Dactylis glomerata. Clin Exp Allergy 1992;22(4):491-7 
    
15. Astwood JD, Hill RD. Cloning and expression pattern of Hor v 9, the group 9 pollen isoallergen from barley. Gene 1996 Dec 5;182(1-2):53-62 
    
16. Potter PC, Berman D, Toerien A, Malherbe D, Weinberg EG. Clinical significance of aero-allergen identification in the western Cape. S Afr Med J 1991;79(2):80-4 
    
17. Baldo BA, Krilis S, Wrigley CW. Hypersensitivity to inhaled flour allergens. Comparison between cereals. Allergy 1980;35(1):45-56

2002

• References