Recombinant Phleum pratense Pollen allergen Phl p 5a, partial 

The cDNA encoding residues Ala1 to Val286 of the Phleum pratense Pollen allergen Phl p 5a full-length protein was fused with a 6xHis-SUMO-tag at the N-terminus and then expressed in E.coli. The purity of this forming recombinant protein is greater than 90% measured by SDS-PAGE. It migrated to the molecular mass band of approximately 45-56 kDa on the gel under reducing conditions. In addition to generating specific antibodies, this recombinant allergen Phl p 5a protein may find uses in the studies of allergen or allergy.

Phl p 5a is an isoform of Phl p 5, which is a group 5 allergen from timothy grass and possesses high reactivity. Phl p 5 is highly allergenic and contains two active domains that lead to the production of high IgE levels. When Phl p 5 is recognized by IgE antibodies of almost all grass pollen allergic patients, strong IgE antibody cross-reactivity and T-cell responses responsible for allergy are induced. Sensitized patients develop heavy clinical reactions such as asthma. N. Najafi etc. demonstrated that Bet v 1-Phl p 5 recombinant fusion proteins form IgE-reactive aggregates with reduced allergenic activity.