Betula verrucosa pollen allergen extract (Bet v)

Allergen proteins contained in Oralvac B2 (often supplemented with the adjuvant Monophosphoryl Lipid A, or MPL) primarily consist of extracts from Betula verrucosa (Birch) pollen. The dominant component is Bet v 1, a member of the pathogenesis-related protein family 10 (PR-10), which is responsible for the majority of IgE sensitization in birch-allergic individuals. Other minor allergens included in such extracts may include profilins (Bet v 2) and polcalcins (Bet v 4), which contribute to cross-reactivity with other plant species and foods. In the context of immunotherapy, these proteins serve as the therapeutic target by interacting with the patient's immune system to desensitize the allergic response. By delivering these proteins sublingually, the treatment aims to reprogram the immune system toward tolerance, reducing the clinical symptoms of allergic rhinitis and asthma triggered by seasonal pollen exposure.

Other names

Birch pollen allergenBetula verrucosa allergen extractOralvac Compact BirchOralvac B2Bet v 1Bet v 2Bet v 4Bet v 6

Allergen-specific immunotherapy (AIT) works by inducing immune tolerance through the repeated administration of specific allergens. This process shifts the immune response from a Th2-dominated profile (associated with IgE production and allergic inflammation) to a Th1 or regulatory T-cell (Treg) response. This leads to the production of IgG4 'blocking' antibodies, which compete with IgE for allergen binding, and the secretion of anti-inflammatory cytokines like IL-10 and TGF-beta, ultimately reducing mast cell and basophil degranulation upon subsequent natural exposure.