Phleum pratense allergen 6 (Phl p 6)

Phleum pratense allergen 6 (Phl p 6) is a major allergen from Timothy grass pollen, a significant contributor to seasonal allergic rhinitis and asthma worldwide [1, 2]. It is an acidic, non-glycosylated protein of approximately 11-13 kDa, characterized by a four-helix bundle structure that is resistant to proteolysis [1, 7]. Phl p 6 is localized in the P-particles of the pollen wall, which are small enough to reach the lower respiratory tract and trigger allergic symptoms [1, 3]. In sensitized individuals, Phl p 6 binds to specific IgE on mast cells and basophils, inducing the release of inflammatory mediators like histamine [1, 4]. It is a critical component in component-resolved diagnosis (CRD), helping to identify genuine sensitization to Pooideae grasses [5, 6]. Therapeutically, Phl p 6 is a target for allergen immunotherapy (AIT), where it is administered in controlled doses to induce immune tolerance [7, 8]. This treatment promotes the production of allergen-specific IgG4 antibodies and regulatory T cells, effectively desensitizing the patient to grass pollen exposure [6, 7].

Other names

Phl p VITimothy grass allergen 6Grass pollen allergen group 6

Allergen immunotherapy (AIT) induces immunological tolerance by shifting the immune response from Th2 to Th1/Treg and promoting the production of allergen-specific IgG4 antibodies that block IgE-mediated allergic reactions [6, 7].