1 Introduction

The global epidemiological burden of allergic diseases has become increasingly substantial, emerging as one of the most prominent public health challenges of the 21st century. According to recent studies, approximately 10% to 30% of the global population is affected by various allergic conditions. Data from the Global Burden of Disease (GBD) study indicate that chronic allergic diseases—including asthma, atopic dermatitis, allergic rhinitis, and food allergy—result in high morbidity and significant health loss in both children and adults.

Traditional allergy diagnosis has long relied on crude allergen extracts, whether employed in skin prick testing (SPT) or serum-specific IgE (sIgE) detection. However, these natural extracts possess inherent and insurmountable limitations. First, their composition is highly heterogeneous and unstable. Originating from biological materials (such as pollen, house dust mites, and foods), the composition of these extracts is influenced by multiple factors including raw material source, growth conditions, harvest season, and manufacturing processes—leading to considerable batch‑to‑batch variability, even among products from the same manufacturer. Second, crude extracts cannot distinguish genuine sensitisation from cross‑reactive sensitisation. Many allergen extracts contain pan‑allergens, resulting in misdiagnosis and unnecessary dietary or environmental avoidance measures that profoundly impair patients' quality of life.

It is against this backdrop that Molecular Allergology has emerged and rapidly risen to become a core driver propelling the allergy field toward precision medicine. The essence of Molecular Allergology lies in shifting the diagnostic focus from complex, heterogeneous allergen mixtures to well‑characterised single allergen components—obtained through genetic engineering or purification techniques—with clearly defined structures and immunological properties. Through the introduction of component‑resolved diagnosis (CRD), this approach not only resolves critical challenges such as cross‑reactivity interference and inaccurate risk assessment but also fundamentally reshapes the diagnostic and therapeutic pathway for allergic diseases, steering it from empiricism toward molecular evidence‑based personalised decision‑making.

2 The Challenge of Cross-Reactivity and IgE Epitope Recognition

2.1 Pan‑allergens and the Cross‑Reactivity Network

Pan‑allergens constitute a class of key sensitising proteins in allergic diseases characterised by highly conserved structures and extensive cross‑reactivity, profoundly influencing both the accuracy of allergy diagnosis and the efficacy of therapeutic strategies. This protein family primarily includes profilins, polcalcins, and non‑specific lipid transfer proteins (nsLTPs), which are ubiquitously distributed across the plant kingdom—with homologues detectable in pollen, fruits, vegetables, and even nuts across diverse taxonomic families. This broad distribution gives rise to a complex cross‑reactivity network: once an individual becomes sensitised to a pan‑allergen from one source, the elicited IgE antibodies can recognise and bind to structurally homologous proteins from other sources, thereby triggering multisystemic, multiorgan allergic symptoms.

2.2 Fine Epitope Mapping of IgE‑Binding Sites

Against this background, fine epitope mapping of IgE‑binding sites has emerged as a central tool for dissecting the sensitisation mechanisms of pan‑allergens. Epitope mapping aims to precisely identify the specific amino acid sequences or conformational regions on allergen molecules that are recognised and bound by patient IgE antibodies. For pan‑allergens, these epitopes are typically located within highly conserved functional domains. Through high‑resolution epitope mapping techniques, researchers can construct IgE recognition profiles for different patient populations against the same pan‑allergen. At the diagnostic level, this provides the molecular basis for component‑resolved diagnosis (CRD). At the therapeutic level, precise epitope information guides the development of next‑generation allergen‑specific immunotherapy (AIT) strategies.

3 Preparation and Characterization of High-Quality Allergen Molecules

The preparation and characterisation of high‑quality allergen molecules constitute a core technological pillar in translating Molecular Allergology from basic research to precise clinical application. Traditional diagnostic and therapeutic approaches based on natural extracts have long been criticised for substantial batch‑to‑batch variability, complex composition, and the presence of numerous non‑allergenic or cross‑reactive impurities—factors that severely compromise the standardisation, precision, and safety of allergy diagnosis and treatment.

Recombinant DNA technology has provided a revolutionary solution for the scalable, standardised production of high‑quality allergen molecules. By cloning genes encoding specific allergen components (such as Bet v 1, Ara h 2, and Der p 1/2) into appropriate expression vectors and introducing them into host systems for expression, precise control over the target protein can be achieved. Following production, allergen molecules must undergo rigorous, multidimensional characterisation to ensure their safety and efficacy as diagnostic reagents or therapeutic vaccines. Functional characterisation represents the most critical step in this entire process, aimed at verifying immunological activity. This includes ELISA or Western blot analysis using serum pools from well‑characterised allergic patients to confirm recognition by specific IgE. The successful preparation and characterisation of these high‑quality allergen molecules directly underpin the advancement of component‑resolved diagnosis (CRD) and the development of next‑generation allergen‑specific immunotherapy (AIT).

4 Next-Generation Molecular Design for Allergen Immunotherapy

The molecular design strategies for next‑generation allergen‑specific immunotherapy (AIT) are undergoing a fundamental transformation—from traditional crude extracts toward precise, safe, and highly effective molecular vaccines. The driving force behind this evolution is the imperative to overcome the inherent deficiencies of natural allergen extracts, including complex composition, substantial batch‑to‑batch variability, and the presence of numerous non‑allergenic or cross‑reactive impurities (such as the pan‑allergens profilin and polcalcin, as well as cross‑reactive carbohydrate determinants, CCDs). These deficiencies not only limit the standardisation and reproducibility of AIT but also increase the risk of adverse reactions. Therefore, guided by the advanced principles of Molecular Allergology, researchers have developed a series of innovative molecular design strategies aimed at rebalancing the immunogenicity and allergenic potential of allergens.

Next‑generation AIT molecular design represents a precision process that is highly interdisciplinary and extensively engineered. It integrates cutting‑edge advances from structural biology, immunology, protein engineering, and nanotechnology—employing diverse strategies including recombinant components, hypoallergenic variants, chimeric designs, and carrier delivery systems—to create next‑generation therapeutic vaccines that effectively induce immune tolerance while offering superior safety profiles. The ultimate goal of these strategies is to achieve truly personalised AIT—optimising treatment regimens "tailor‑made" according to each patient's precise sensitisation profile—thereby fundamentally transforming the therapeutic landscape for allergic diseases.

5 Conclusion and Future Perspectives

The current field of allergy diagnosis and treatment stands at a critical juncture, transitioning from traditional empirical models toward a precision medicine paradigm. The rise of Molecular Allergology—particularly the clinical implementation of component‑resolved diagnosis (CRD)—has fundamentally resolved the core challenges of cross‑reactivity interference and inaccurate risk assessment that plagued traditional crude extract‑based diagnostics, thereby establishing a solid foundation for personalised therapy. Building on this foundation, next‑generation AIT development is increasingly focused on leveraging recombinant DNA technology and protein engineering to create structurally defined, safe, and predictably efficacious "molecular vaccines." Nevertheless, this transition continues to encounter multiple technical barriers. Despite the challenges ahead, the synergistic advancement of molecular biology, immunology, materials science, and computational sciences heralds a new era of safer, more efficacious, and more personalised allergy therapeutics—one that is now clearly within sight.

How to Choose and Buy?

For researchers interested in exploring our allergen product portfolio, BOT Bioscience offers custom protein expression, antibody production, and conjugation services to meet your specific application requirements. Visit our Allergen page to explore the full range of products—from pollen and dust mite allergens to food and animal dander allergens—and request a quote today.

[1]      Maison, N., & Omony, J. (2026). Current challenges in allergic diseases and computational solutions towards personalized medicine. Frontiers in Allergy, 7. https://doi.org/10.3389/falgy.2026.1740694

[2]      Pechsrichuang, P., & Jacquet, A. (2020). Molecular approaches to allergen‐specific immunotherapy: Are we so far from clinical implementation? Clinical & Experimental Allergy, 50(5), 543–557. https://doi.org/10.1111/cea.13588