PhI p 1

Pollen allergens are a significant cause of allergic reactions, particularly in individuals with respiratory allergies. One of the major allergens from grass pollen is Phl p 1, which is derived from the pollen of Timothy grass (Phleum pratense). Recombinant Phl p 1 (rPhl p 1) is a non-glycosylated protein produced in Escherichia coli (E. coli) cells that carry a cloned cDNA encoding the Phl p 1 allergen . This recombinant form closely resembles the natural Phl p 1 and is used extensively in allergy diagnostics and research.

The gene encoding Phl p 1 is obtained by reverse transcription on an mRNA template isolated from Timothy grass pollen. This gene is then cloned into a plasmid vector, such as pET23a+, for prokaryotic expression in E. coli . The recombinant protein is purified using techniques like anion exchange and affinity chromatography, resulting in a high-purity product suitable for immunological studies .

Phl p 1 is considered one of the most important species-specific allergens of Timothy grass, followed by Phl p 5 . It binds to Immunoglobulin E (IgE) in the majority of patients with grass pollen allergies, indicating that it shares many of the IgE epitopes with natural group 1 grass pollen allergens . Recombinant Phl p 1 has been shown to bind IgE of more than 90% of grass pollen allergic patients . Its biological activity has been demonstrated through histamine release and skin test experiments .

Recombinant allergens like Phl p 1 are used in immunological test systems for the diagnosis of type I hypersensitivity. These systems involve whole allergen extracts, highly purified allergens from the extracts, and their recombinant analogues obtained by gene engineering techniques . The use of recombinant Phl p 1 in diagnostic assays allows for the precise identification of specific IgE antibodies in patients’ serum, aiding in the accurate diagnosis of grass pollen allergies .