Inherent allergic potential of α-dioxygenase fragment: A pathogenesis related protein

In the course of analyzing amino acid sequence of an allergen (≈20 kDa), we found this protein has a homology with the amino acid sequence of putative α-Dioxygenase fragment (ADF). Allergy caused by many allergens having an enzymatic activity have been reported previously, but allergenicity to neither α-Dioxygenase enzyme nor to it's any constituents has been reported. We sought to purify an ADF (≈19.5 kDa) from chickpea to investigate it's inherent allergic potential in BALB/c mice. The ADF showed IgE-affinity in sera of sensitized BALB/c mice and allergic patients. Enhanced levels of histamine, specific IgE as well as IgG1, IL-4, IL-17, IL-6, IL-2 and IL-10 were observed in the sera of mice treated with ADF allergen. A positive skin Type 1 test and elevated number of mast cells were found in the treated mice. Apart from this, enhanced number of immune cells i.e. CD19+ and CD4+ were also noticed in the ADF treated group. Higher expressions of IL-4 as well as GATA-3 and prominent histological changes were observed in tissues of treated animals. Furthermore, expressions of Th2 cytokines, associated transcription factors and mast cell signaling proteins were also increased at mRNA and protein levels in the intestines of ADF treated mice. Conclusively, present study demonstrated that ADF with molecular weight of 19.5 kDa is a clinical relevant allergen which causes allergic immune responses in BALB/c mice and may play a pivotal role in allergy caused by food containing α-Dioxygenase enzyme in sensitive individuals.