Grass pollen-specific immunoglobulin G (sIgG)

Grass pollen-specific immunoglobulin G (IgG) antibodies, particularly the IgG4 subclass, are key mediators of immune tolerance induced by allergen immunotherapy (AIT) for hay fever and allergic asthma (Journal of Allergy and Clinical Immunology, 2012; Frontiers in Immunology, 2022). These antibodies are often termed 'blocking antibodies' because they compete with allergen-specific IgE for binding to grass pollen allergens, such as those from Timothy grass (Phleum pratense) (Allergy, 1995; NIH, 2016). By sequestering these allergens, they prevent the cross-linking of IgE on the surface of mast cells and basophils, thereby inhibiting the release of inflammatory mediators like histamine and leukotrienes (NIH, 2016). Furthermore, grass pollen-specific IgG can engage the inhibitory receptor FcγRIIb on B cells and effector cells, which actively suppresses IgE-mediated signaling and facilitated allergen presentation to T cells (NIH, 2022; Frontiers in Immunology, 2022). In clinical settings, the rise in serum levels of these antibodies is used as a primary biomarker to monitor the efficacy of subcutaneous or sublingual immunotherapy and reflects a successful shift in the immune system toward a non-allergic, tolerant state (AAAAI, 2018; MDPI, 2021). While they are not classical therapeutic targets like receptors or enzymes, their induction is the primary goal of grass pollen AIT (NIH, 1999; NIH, 2006).

Other names

Grass pollen-specific IgGGrass pollen-specific IgG4Blocking antibodiessIgG (Grass)

Induction of allergen-specific IgG (primarily the IgG4 subclass) that competes with IgE for allergen binding and signals through the inhibitory receptor FcγRIIb to suppress allergic inflammation.