Uyen Quynh Nguyen1, Chi Thi Linh Nguyen1, Phuong Mai Vu1, Truong Huu Nguyen2, Phuong Hoang Nguyen2, Vinh Van Hoang1*
1Vietnam National University Hanoi, Institute of Microbiology and Biotechnology, Hanoi 10000, Vietnam
2Allergy and Clinical Immunology Center, Bachmai Hospital, Hanoi 10000, Vietnam
*Corresponding author’s email: vinhhv@vnu.edu.vn
Received: 17 July 2025 / Accepted: 20 September 2025 / Published Online: 08 October 2025
Abstract
Blomia tropicalis, a common house dust mite, serves as a significant indoor allergen in tropical climates such as Vietnam. Precise identification of key allergens plays a crucial role in enabling component-resolved diagnostics and applying allergen-specific immunotherapies. In this study, we investigated the recombinant expression and immunological evaluation of Blo t 1, a cysteine protease allergen obtained from B. tropicalis isolated in Vietnam. The Blo t 1 gene, after codon optimization and signal peptide removal, was cloned into the pPICZα A vector and expressed in Pichia pastoris. IgE-binding ability of the recombinant Blo t 1 was assessed using sera from 53 subjects (21 males, 32 females; aged 6–72 years), including 29 patients sensitized to B. tropicalis and 24 non-allergic controls. The purified recombinant protein with an approximate molecular weight of 47 kDa, including ~37 kDa from the truncated Blo t 1 sequence, a C-terminal His-tag, and ~10 kDa from the α-factor secretion signal, was purified using His-tag affinity chromatography. Dot blot results indicated that 23 out of the 29 allergic sera (79.3%) displayed IgE reactivity to the Blo t 1, which was further validated by western blot analysis. These findings support that Blo t 1 is a major allergen in the Vietnamese population and highlight its potential as a molecular tool for improving the accuracy of allergy diagnostics and the development of targeted immunotherapies in Vietnam. This work also adds to the limited data on B. tropicalis allergens expressed in yeast systems.
Keywords: Allergen, Blomia tropicalis, Blo t 1, IgE-binding reactivity, Pichia pastoris
