g208 nPhl p 4 Timothy

Allergens within Grass Pollens

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  • Latin name: Phleum pratense
  • Source material: Phleum pratense pollen (purified native)
nPhl p 4
Phl p 4 belongs to the group 4 grass pollen allergens, which are basic glycoproteins, approximately 55 kD in size. Using monoclonal antibodies, representatives of this group have been detected in pollen of a range of grass species (1-2) and characterized in some detail from Phleum pratense (1-3) and Dactylis glomerata (4). Phl p 4 is considered major allergen, binding IgE antibodies from up to 75% of grass pollen sensitized subjects. No group 4 grass pollen allergen has so far been cloned.
 
Single components from timothy grass, Phleum pratense, are available for specific IgE testing, produced either with recombinant technique or as purified native proteins. As an alternative the next generation of immunotherapy may be based on recombinant allergen components, possibly modified to reduce the risk of anaphylaxis. If the sensitization profile to e.g. timothy is known, only those components to which the patient is actually sensitized should be relevant for therapy. This would eliminate the risk that the therapeutic reagent induces IgE antibodies to additional components. The single components of timothy in specific IgE tests may also be used for monitoring immunotherapy with the natural extract.

rPhl p 7, a two-EF-hand Ca2+-binding protein is likely to cross-react with pollen proteins from most plants, in particular with other grass species, trees of the Fagales order, olive and weeds. rPhl p 12;  profilin from timothy is a so-called pan-allergen that may be involved in cross-reactivities seen between many different plants, including plant-derived foods (examples of other profilins: Hev b 8 = profilin in Latex (Hevea braziliensis), Bet v 2 = profilin in Birch (Betula verrucosa)). However, both rPhl p 7 and rPhl p 12 have shown to be minor allergens and the clinical consequence of the speculated cross-reactivity with other plants is probably not of major importance, but cannot be excluded.

References:

    1. Fahlbusch, B., Muller, W. D., Diener, C. H. and Jäger, L. (1993). Detection of crossreactive determinants in grass pollen extracts using monoclonal antibodies against group IV and group V allergens. Clin. Exp. Allergy 23:51-60.
    2. Fahlbusch, B., Muller, W. D., Rudeschko, O., Jager, L., Cromolecular weightell, O. and Fiebig, H. (1998). Detection and quantification of group 4 allergens in grass pollen extracts using monoclonal antibodies . Clin. & Exp. Allergy 28:799-807.
    3. Fischer, S., Grote, M., Fahlbusch, B., Müller, W. D., Kraft, D. and Valenta, R. (1996). Characterization of Phl p 4, a major timothy grass (Phleum pratense) pollen allergen. J. Allergy Clin. Immunol. 98:189-198.
    4. Leduc-Brodard, V., Inacio, F., Jaquinod, M., Forest, E., David, B. and Peltre, G. (1996). Characterization of Dac g 4, a major basic allergen from Dactylis glomerata pollen. J. Allergy Clin. Immunol. 98:1065-1072.

2002



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