Characterization of the clinical relevance and hypoallergenic peptides of the newly evidenced major allergen Hum j 1

Jin-Lyu Sun^1*Ya-Li Cheng¹Qiong Li²YongShi Yang¹Yibo Hou¹Zhiqiang Xu^3*Ji-Fu Wei^2*

• ¹Department of Allergy, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
• ²Department of Pharmacy, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, China
• ³Department of Pharmacy, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China

Background: Humulus japonicus (HJ) pollen is a predominant autumn allergen in northern China. A 10 kDa protein termed Hum j 1 was proposed as a major allergen, but its uncertainty hindered its clinical application. This study aims to investigate the clinical relevance of Hum j 1 and screen hypoallergenic peptides for potential application in molecular diagnosis and immunotherapy.Methods: Serum samples from 93 HJ pollen-allergic patients were analyzed for IgE reactivity against recombinant Hum j 1 (rHum j 1). We evaluated correlations between IgE responses to rHum j 1 and HJ pollen crude extracts using Spearman’s rank correlation analysis. The association of clinical symptoms with Hum j 1-IgE positivity was evaluated by group comparisons and multivariable analyses. Allergenicity of Hum j 1 was further investigated by immunoblotting and basophil activation tests. Six KLH-coupled peptides spanning Hum j 1 sequence were synthesized to assess hypoallergenicity and IgG-mediated inhibitory effects against allergen-specific IgE binding in a murine model.Results: rHum j 1 demonstrated IgE reactivity in 74.2% (69/93) of patients and induced significant basophil activation. rHum j 1-specific IgE levels showed a moderate positive correlation with crude extract-specific IgE levels (Spearman’s ρ = 0.529, p < 0.0001). Patients with allergic rhinitis complicated by asthma had significantly higher levels of Hum j 1-sIgE (p = 0.014). We found a significant association between Hum j 1 sensitization and asthma in multivariate analysis (OR = 3.98, 95% CI: 1.2-13.0, p = 0.02), with Hum j 1-sensitized patients showing higher asthma prevalence compared to non-sensitized individuals (46% vs. 17%, p = 0.010). All peptides showed significantly reduced IgE reactivity (p < 0.0001) and minimal basophil activation. Immunized mice produced high-titer IgG antibodies that inhibited patient IgE binding to rHum j 1 by 22.09–64.61%.Conclusions: Hum j 1 could enhance the sensitivity of HJ pollen crude extract-based IgE assays. IgE reactivity to Hum j 1 was more frequently associated with allergic asthma. The hypoallergenic linear peptides of the Hum j 1 laid the foundation for the development of molecular vaccine for AIT. These findings would contribute to developing diagnostic and therapeutic strategies for HJ pollinosis.