Timothy grass pollen allergen Phl p 5b (Phl p 5b)

Timothy grass pollen allergen Phl p 5b is a major protein allergen derived from the pollen of Phleum pratense, which is one of the most clinically relevant grass species causing seasonal allergies worldwide (UniProt: P43176). As a major allergen, Phl p 5b is recognized by serum IgE in over 90% of grass-pollen-allergic individuals and possesses high intrinsic allergenic potency, capable of triggering robust mast cell degranulation (PubMed: 11149991). In the context of biotechnology and clinical medicine, Phl p 5b serves as a primary target for allergen-specific immunotherapy (AIT), where it is administered in controlled doses to desensitize the immune system. Therapeutic products containing this allergen, such as Grazax and Oralair, work by reorienting the immune system toward tolerance, specifically by inducing regulatory T cells and increasing the levels of IgG4 antibodies that block IgE-mediated responses (WHO/IUIS Allergen Database). Despite its therapeutic utility, Phl p 5b presents a significant safety challenge due to the risk of inducing anaphylaxis during the administration of immunotherapy. Accurate identification and quantification of Phl p 5b are essential for the standardization of diagnostic tests and the formulation of effective desensitization vaccines.

Other names

Major pollen allergen Phl p 5bPhl p VbPhl p 5.02Isoallergen Phl p 5.0201Phleum pratense allergen 5b

Allergen-specific immunotherapy (AIT) utilizes Phl p 5b to induce peripheral T-cell tolerance, shift the immune response from a Th2 to a Th1/Treg profile, and stimulate the production of allergen-specific IgG4 'blocking' antibodies that compete with IgE for allergen binding (NIH: PMC4210655).