Major pollen allergen Phl p 2 (Phl p 2)

Major pollen allergen Phl p 2 is a clinically significant protein allergen derived from Phleum pratense (Timothy grass), which is a major contributor to seasonal respiratory allergies globally (UniProt: P43214). This small, acidic protein (approximately 10-12 kDa) belongs to the group 2 grass pollen allergen family and is recognized by IgE antibodies in the majority of grass pollen-allergic individuals (IUIS Allergen Nomenclature). Structurally, Phl p 2 adopts a beta-barrel fold similar to the C-terminal domain of expansins, although its precise biological function in the plant is largely associated with pollen-specific structural roles. In therapeutic contexts, Phl p 2 is a key component in allergen-specific immunotherapy (AIT) products, such as Timothy grass extracts and recombinant vaccines like BM32, which aim to desensitize the immune system (PubMed: 27154245). The target is primarily used to induce protective IgG antibodies and regulatory T cells to mitigate allergic symptoms such as rhinitis and asthma upon subsequent environmental exposure to grass pollen (PubMed: 10471111).

Other names

Allergen Phl p IIPhl p 2.0101Timothy grass pollen allergen Phl p 2

Allergen-specific immunotherapy (AIT) utilizes the allergen to induce peripheral T-cell tolerance, promote a shift from a Th2 to a Th1/Treg immune profile, and stimulate the production of allergen-specific IgG4 blocking antibodies that prevent IgE-mediated mast cell degranulation.