g209 rPhl p 6 Timothy

Allergens within Grass Pollens

Print Print icon Tell a friend Tell a friend icon
  • Latin name: Phleum pratense
  • Source material: An E. coli strain carrying a cloned cDNA encoding the Phleum pratense allergen Phl p 6.
rPhl p 6
Phl p 6 is a 12 kD Phleum pratense pollen protein that binds IgE antibodies from 50% or more of grass pollen sensitized subjects. The occurrence of Phl p 6 appears restricted to P. pratense and based on sequence similarity to the larger group 5 allergens, this group is thought to represent its ancestral origin. Cloning and analysis of Phl p 6 was described by Petersen et al. (1-2) while Vrtala et al. (3) recently reported on detailed localization and structural studies.

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. Petersen, A., Bufe, A., Schramm, G., Schlaak, M. and Becker, W.-M. (1995a). Characterization of the allergen group VI in timothy grass pollen (Phl p 6). II. cDNA cloning of Phl p 6 and structural comparison to grass group V. Int. Arch. Allergy Immunol. 108:55-59.
    2. Petersen, A., Bufe, A., Schramm, G., Schlaak, M. and Becker, W.-M. (1995b). Characterization of the allergen group VI in timothy grass pollen (Phl p 6). I. Immunological and biochemical studies. Int. Arch. Allergy Immunol. 108:49-54.
    3. Vrtala, S., Fischer, S., Grote, M., Vangelista, L., Pastore, A., Sperr, W. R., Valent, P., Reichelt, R., Kraft, D. and Valenta, R. (1999). Molecular, immunological, and structural characterization of Phl p 6, a major allergen and P-particle-associated protein from timothy grass (Phleum pratense) pollen. J. Immunol. 163:5489-5496.

2002



Further Reading