Holcus lanatus pollen allergen (Hol l 1, Hol l 2, Hol l 4, and Hol l 5)

Holcus lanatus (common velvet grass) pollen contains multiple allergenic proteins that trigger allergic responses in sensitized individuals. The primary allergen components include four characterized molecules: Hol l 1 (a Group 1 beta-expansin), Hol l 5 (a Group 5 ribonuclease), Hol l 4 (a Group 4 berberine bridge enzyme), and Hol l 2 (a Group 2 protein with unknown biological function). H. lanatus is a perennial grass distributed worldwide in temperate regions and is a significant source of pollen allergens, with over 77% of individuals with seasonal allergic rhinitis showing positive reactions to cutaneous provocation with its pollen. Upon inhalation or contact with mucous membranes, these water-soluble allergens bind to IgE antibodies in allergic individuals, triggering histamine release and resulting in respiratory and cutaneous symptoms including allergic rhinitis, hay fever, and potentially asthma. H. lanatus allergens exhibit substantial cross-reactivity with allergens from other grass species in the Pooideae subfamily, particularly Group 1 and Group 5 allergens, complicating clinical diagnosis and immunotherapy. The pollen is primarily used for allergenic testing and diagnosis rather than as a therapeutic drug target.

Other names

Common velvet grass allergenVelvet grass pollen allergenYorkshire fog allergenCreeping soft grass allergenMeadow softgrass allergen

IgE-mediated allergic reaction. The pollen contains water-soluble allergenic proteins that are released upon contact with mucous membranes or after hydration, binding to IgE antibodies in sensitized individuals and triggering histamine release and immune responses.