Grass and rye pollen allergens (GPA)

Grass and rye pollen allergens are a complex group of clinically significant proteins derived from the pollen of various species within the Poaceae family, including Timothy grass (Phleum pratense) and Rye grass (Lolium perenne) (Allergen.org, 2024). These allergens, particularly the Group 1 (expansins) and Group 5 (ribonucleases) proteins, are primary drivers of seasonal allergic rhinitis, conjunctivitis, and allergic asthma worldwide (PubMed, PMID: 24304361). When inhaled by sensitized individuals, these proteins interact with specific IgE antibodies bound to the surface of mast cells and basophils, triggering the release of inflammatory mediators like histamine. In clinical medicine, these allergens serve as the active pharmaceutical ingredients in allergen immunotherapy (AIT) products, such as sublingual tablets or subcutaneous injections. The therapeutic goal is to modify the underlying immune response by inducing immunological tolerance, thereby providing long-term relief from symptoms and preventing the progression of allergic disease (FDA, 2014). This treatment aims to shift the immune profile from a Th2-mediated allergic response to a regulatory and Th1-mediated response.

Other names

Poaceae pollen allergensGramineae pollen allergensGrass pollen extractRye grass pollen extractHay fever allergensTimothy grass pollen allergen extractMixed grass pollen allergens

The mechanism of action for drugs targeting these allergens involves allergen immunotherapy (AIT). This process induces peripheral T-cell tolerance by increasing the production of regulatory T cells (Tregs) and suppressive cytokines such as IL-10 and TGF-beta (Nature Reviews Immunology, 2014). Furthermore, it promotes a shift from a Th2-biased immune response to a Th1-biased response and stimulates B cells to produce allergen-specific IgG4 antibodies. These IgG4 antibodies act as blocking antibodies that compete with IgE for allergen binding, thereby preventing the cross-linking of IgE on mast cells and basophils and subsequent degranulation (PubMed, PMID: 21856505).