MARL Research Themes

Major research themes of the Molecular Allergy Research Laboratory:

• Immunological and biophysical characterization of major and minor allergens in fish, crustacean and mollusk
• Generation of recombinant allergens for improved diagnosis of food allergy
• Novel immunotherapeutic candidates for food allergy
• Improved in vitro diagnostics for pediatric food allergy
• Sensitive immunoassay platforms for rapid and accurate quantification of allergenic protein
• Natural bioactive compounds for treating gut-related disorders
• High-throughput bioinformatics discovery platform for rapid allergen identification
• Inhalational exposure and sensitization to food allergens in the workplace
• Detection and quantification of allergens in processed food

Immunological and biophysical characterization of major and minor allergens in fish, crustacean and mollusk

Discovery of allergens in various food and inhalant sources is central to our understanding of the molecular mechanisms of allergic reactions. Allergen characterization is the most important underlying factor for better patient management through specific diagnostics and the design and development of novel immunotherapeutics. Of the ‘‘Big eight’’ allergen food groups, fish and shellfish present a unique challenge in terms of allergen discovery due to the large number and diversity of consumed species, leading to heterogeneity of allergen structure and cross-reactivity among various sources. Co-sensitization and clinical cross-reactivity of patients with fish, crustacean and/or mollusk allergy is often described; however, the current diagnostic approaches to manage these patients are not based on sufficient molecular knowledge of these seafood allergens.

Through our detailed molecular studies on over 160 seafood species in our laboratory, and the analysis of IgE antibody binding patters of over 300 patients, we are able to identify and characterize a range of allergenic proteins of clinical importance. At present we have identified and purified over 15 allergenic proteins from different fish species, including parvalbumin, aldolase, enolase, collagen and vitellogenin. Among the different shellfish (crustacean and mollusk) species we identified and purified over 20 allergenic proteins, including tropomyosin, myosin light chain, sarcoplasmic binding protein and arginine kinase.

Our laboratory has officially registered 10 fully characterized seafood allergens with the World Health Organization and International Union of Immunological Societies Allergen Nomenclature Database.

Generation of recombinant allergens for improved diagnosis of food allergy

The focus of generating recombinant allergens has been on the discovery and characterisation of novel major allergens, IgE epitope mapping studies, development of novel allergy diagnostic platforms, therapeutic research and for research elucidating immune mechanisms of food allergy. Our research has led to the generation of a vast inventory of recombinant proteins for major inhalant and food allergens using high-yield expression systems and purification using state-of-the-art protein chromatographic purification facilities. Our primary focus is on the use of purified natural or recombinant allergens in the development of component resolved diagnostics for food

Novel immunotherapeutic candidates for food allergy

Food allergy is an evolving health issue, which has seen a significant rise in the past decade with nearly 8% of the world’s population affected. Importantly, the long-term implications for disease burden are substantial among children with food allergy to eggs, milk, peanut, fish and shellfish. Immunotherapeutic strategies to induce desensitisation and tolerance among individuals with food allergy are still in the developmental stages and innovative approaches are required to establish safe methods to generate tolerance to major food allergens. Our research will elucidate the hypoallergenic yet immunogenic regions of major food allergens that have been implicated in paediatric food allergy and develop novel hypoallergenic proteins, with the ability to induce an IgG “blocking” response, without resulting in any IgE-mediated reactions.

Improved in vitro diagnostics for pediatric food allergy

Food allergy is a major and increasing health problem. The rates of food allergy have more than tripled in the last decade worldwide with Australia leading this epidemic. Allergy to seafood amongst Australians is common with 3% of children in the region. The prevalence of shellfish allergy is often higher than that of fish allergy, with prawn and crab are the major causes of anaphylaxis in both children and adults. Allergic reactions to seafood are often serious, with seafood allergy now the leading cause of food related fatality from anaphylaxis in Australia. Despite this, there are significant restrictions on the ability to adequately diagnose and manage this life-threatening disease in Australia. We improve the current diagnostics for seafood allergy in children in close collaboration with The Children’s Hospital at Westmead (Sydney), the Murdoch Children’s Research Institute (Melbourne) and the Centre for Food & Allergy Research (NHMRC Centre of Research Excellence).

Sensitive immunoassay platforms for rapid and accurate quantification of allergenic proteins

One of our key research focus is on the design and development of novel platforms for specific and sensitive IgE antibody based diagnostic assays. As it is known that the amount of total IgE is not correlated with the amount of allergen-specific IgE, it is beneficial to develop diagnostic assays for the detection of allergen-specific IgE rather than total IgE. With our 96-well plate assay format ImmunoPCR approach, it would be possible to develop a screening system against multiple allergens in one test. This would give the same benefits of allergy profiling that current microarray approaches offer. Correctly determining allergen sensitivity and cross-reactivity is invaluable information to the proper management of a food allergy. Our assay provides an alternative platform for profiling which would be simple and cost effective. This assay is especially attractive to the analysis of multiple allergen in the research laboratory setting.

Natural bioactive compounds for treating gut-related disorders

A new era in medical science has dawned with the realization of the critical role of the gut in health and disease. Poor gut health also impacts directly on several major diseases including intestinal disorders, Crohn’s disease and colitis (IBD), but also on extra-intestinal disorders including asthma, metabolic syndrome and even food allergy. The objective of this proof-of-concept research is to generate scientific evidence regarding the beneficial physiological effects of purified natural polysaccharide from seaweeds, grown and purified in Australia. Based on in vivo functional studies demonstrating the safety and immuno-stimulatory activity of the purified polysaccharides, this project will investigate the improvements of gut health and thereby the positive influence on the management of several gastrointestinal illnesses in Australia and worldwide.

High-throughput bioinformatics discovery platform for rapid allergen identification

Recent advances in the field of genomic, bioinformatics and proteomics have unlocked new opportunities for targeted high-throughput screening and identification of proteins in silico based on amino acid homologies, resulting in direct comparative analysis of similar allergens from comprehensive allergen databases. Thus, the combinatorial approach using a specific organism’s genome data and comparison with a growing number of comprehensive allergen databases, immune-reactivity and high throughput protein sequence assessment can overcome the current limitations of allergen identification. Our group’s comprehensive discovery pipeline utilizing biochemical and computational tools in addition to antibody reactivity is a significant improvement over current approaches for the identification and characterization of allergenic proteins, providing a new tool for researchers developing better diagnostics and novel immunotherapeutics.

Inhalational exposure and sensitization to food allergens in the workplace

Occupational asthma and subsequent food-induced allergic reactions among seafood workers due to air-borne allergen exposure is a frequent occurrence. There is a lack of standardized, validated methods for monitoring the allergen concentrations in bio-aerosols generated during food processing. Traditionally, serum IgE antibodies from sensitized individuals have been used to detect air-borne allergens. Our research focuses on the development of polyclonal and monoclonal antibody-based immunoassays as well as mass spectrometric based detection platforms for the sensitive detection and quantification of air-borne fish and crustacean allergens. Our methodological approach used for developing these platforms offers opportunities to other food industries to monitor air-borne allergens, so as to improve work-safety and occupational health.

Detection and quantification of allergens in processed food

Undeclared allergens in packaged food present a serious health risk to consumers, particularly allergic individuals. There is currently no cure for food allergy, so management relies on strict food avoidance. The Australian and New Zealand Food Standards Code requires a declaration of the presence of eleven different allergens made through the label on a product of food. However, despite mandatory food-labelling laws, accidental ingestion of undeclared allergens in food products is common, causing frequent and sometimes life-threatening or fatal reactions.

To detect and quantify undeclared allergens in processed food we have developed several novel tests using allergen specific antibodies as well as a panel of signature peptides in combination with advanced mass spectrometry. This method is now offered by the National Measurement Institute (NMI, Melbourne) to the Australian food industry to protect consumer of fatal exposure to cross-contaminated allergens.