DOI: 10.5415/apallergy.0000000000000312 ISSN: 2233-8268
Cloning, expression, and allergenicity of the indoor mite Suidasia pontifica allergen Sui p 2
Cristian Floren L. Arevalo, Sarah Hannah Eunice G. Consul, Pauline Therese B. Dayo, Aubrey Maegan S. Apelario Ong, Karina Teresa B. Alve, Veronica S. David, Mary Julienne M. Mamaradlo, John Donnie A. Ramos
Background:
Suidasia pontifica
(Sp) is a clinically important species of indoor mite (IM). Sui p 2, a group 2 allergen homolog from Sp, was predicted to contain conserved amino acids that may form allergenic epitopes. Given the clinical relevance of the well-documented IM group 2 allergens, Sui p 2 may be a medically important allergen in mite allergy.
Objectives:
This study aimed to clone, express, and purify recombinant Sui p 2 and determine its allergenicity in the Filipino allergic population.
Methods:
The 381 bp open reading frame of the
Sui p 2
gene was cloned into the pET 16b vector and transformed into
Escherichia coli
BL21 (DE3). Cloning was verified by BamHI restriction enzyme digestion, polymerase chain reaction, and gene sequencing. Protein expression and purification were resolved using sodium dodecyl sulfate polyacrylamide gel electrophoresis and His-tag protein-purified magnetic beads iminodiacetic acid-nickel. Indirect immunoglobulin E (IgE) enzyme-linked immunosorbent assay was used to assess the allergenicity of the recombinant Sui p 2 (rSui p 2). Demographic profiles of the patients were assessed to see their association with allergic sensitization.
Results:
The expected 6035 bp plasmid with a 381 bp gene insert was observed in the transformants, along with a distinct clean ~13.5 kDa band, indicating successful rSui p 2 expression and purification. The purified rSui p 2 reacted with the IgE of 64.6% (
P
< 0.001) of Sp-reactive individuals and showed a high average inhibition (57.73%) to the IgE binding to Sp extract. Interestingly, urban living was the only significant demographic protective factor (odds ratio, 0.1211) for Sp sensitization.
Conclusion:
This study presents the first report on the cloning, expression, and IgE characterization of rSui p 2. The inclusion of rSui p 2 in the development of Sp-specific diagnostics and its potential immunotherapeutic use for IM allergies among IM-allergic patients is a possibility pending more subsequent verifications.