Molecular and immunochemical characterization of Pop n 2: A new allergen of Populus nigra pollen

Abstract

Background Pollen is one of the most common allergens that cause respiratory allergies worldwide. Pollen grains from poplars have been reported as important sources of pollinosis in many countries. Objective The aim of the present study was to determine the molecular and immunochemical characterization of Pop n 2, a novel allergen of Populus nigra (P nigra) pollen extract. Methods In this study, the pollen extract of P nigra was analysed by SDS‐PAGE, and the allergenic profile was determined by IgE immunoblotting and specific ELISA using the sera of twenty allergic patients. The coding sequence of Pop n 2 was cloned and expressed in the Escherichia coli BL21 (DE3) using plasmid the pET‐21b (+). Finally, the expressed recombinant Pop n 2 was purified by affinity chromatography. Results Pop n 2 belongs to the profilin family with a molecular weight of approximately 14 kDa. Pop n 2 is the most IgE‐reactive protein (about 65%) in the P nigra pollen extract. The cDNA sequencing results indicated an open reading frame 396 bp that encodes 131 amino acid residues. The results of ELISA and Immunoblotting assays showed that recombinant Pop n 2 could react with the IgE antibody in patients' sera, like its natural counterpart. Conclusion Our data revealed that Pop n 2 is a significant allergen in the P nigra pollen extract. Moreover, we observed that the recombinant Pop n 2 produced by the pET‐21b (+) vector in the E colisystem acts as its natural counterpart.

Newly defined allergens in the WHO/IUIS Allergen Nomenclature Database during 01/2019‐03/2021

“…22 As profilins, ubiquitous cross-reactive plant proteins, are significantly associated with allergy to grass pollen and to Cucurbitaceae fruits, 23 the clinical impact of profilin sensitizations is being continuously updated and expanded. 24 Three new profilins received official designations, Pop n 2 from the black poplar (Populus nigra), 25 Amb t 8 from giant ragweed (Ambrosia trifida) pollen, 5 and Can s 2 from hemp (Cannabis sativa). 26 The profilin from sawtooth oak, Que ac 2, was also included in the ANDB.…”

Developments in the field of allergy in 2020 through the eyes of Clinical and Experimental Allergy

“…Other work covered the issue of product availability for venom immunotherapy in the UK, 115 epidemiology of allergic and respiratory disease 116‐119 , 120 , 121 occupational allergies, 122‐124 advances in allergy diagnostics 125‐133 , 134 , 135 , 136 , animal model work 137 138 , 139 , 140 , 141 , investigation of infant airway epithelium, 142 a possible association between tree pollen exposure and reduced lung function 143 and evaluations of allergy service delivery 144‐147 …”

Allergic diseases and novel targets in allergen immunotherapy

“…Notably, identifying pro-allergenic compounds within the pollen grain is fundamental for the successful design of allergen-specific immunotherapies and the diagnostics of the condition. To address this gap, Shams et al 6 generated a highly purified poplar pollen extract, proteins of which were separated using SDS-PAGE. Then, sera of 20 P nigra sensitized individuals containing P nigra-specific IgE was used for immunoblotting and identification of proteins of the most remarkable reactivity; 14 kDa profilin Pop n 2 was identified.…”