Major ragweed pollen allergen Amb a 1 (Amb a 1)

Amb a 1 is the immunodominant allergen of short ragweed (Ambrosia artemisiifolia), responsible for the majority of ragweed-induced allergic rhinitis and asthma cases. Biologically, it is a pectate lyase enzyme that facilitates pollen tube growth by degrading pectin in the plant cell wall (UniProt: P18145). In the context of Amb a 1 – ISS/ODN, the allergen is covalently linked to immunostimulatory DNA sequences (ISS), which are phosphorothioate oligodeoxynucleotides containing CpG motifs. This conjugate, also known as Tolamba or AIC, acts as a therapeutic vaccine by targeting Toll-like receptor 9 (TLR9) on dendritic cells and B cells (Marshall et al., Int Immunopharmacol, 2001). The mechanism involves shifting the immune response from a pro-allergic Th2 profile to a Th1-biased profile, thereby increasing protective IgG antibodies and reducing allergen-specific IgE and inflammatory cytokine production (Creticos et al., N Engl J Med, 2006). This approach aims to provide a safer and more rapid desensitization compared to traditional allergen extracts (Simons et al., J Allergy Clin Immunol, 2004).

Other names

Amb a 1Amb a IPectate lyaseAICTolambaAmb a 1-ISS conjugateRagweed allergen Amb a 1

The conjugate acts as a TLR9 agonist and allergen-specific immunotherapeutic agent, promoting a Th1-biased immune response and inducing T-cell tolerance to suppress Th2-mediated allergic inflammation.