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Soybean (Glycine max) allergy can be life threatening. A lack of causative immunotherapy of soybean allergy makes soybean avoidance indispensable. Detection methods are essential to verify allergen labeling and unintentional allergen cross contact during food manufacture. Here, we aimed at evaluating our previously described primers for loop-mediated isothermal amplification (LAMP) of multicopy gene ORF160b, combined with a lateral flow dipstick (LFD)-like detection, for their performance of soybean detection in complex food matrices. The results were compared with those obtained using quantitative real-time Polymerase Chain Reaction (qPCR) as the current standard of DNA-based allergen detection, and antibody-based commercial lateral flow device (LFD) as the current reference of protein-based rapid allergen detection. LAMP-LFD allowed unequivocal and reproducible detection of 10 mg/kg soybean incurred in three representative matrices (boiled sausage, chocolate, instant tomato soup), while clear visibility of positive test lines of two commercial LFD tests was between 10 and 102 mg/kg and depending on the matrix. Sensitivity of soybean detection in incurred food matrices, commercial retail samples, as well as various processed soybean products was comparable between LAMP-LFD and qPCR. The DNA-based LAMP-LFD proved to be a simple and low-technology soybean detection tool, showing sensitivity and specificity that is comparable or superior to the investigated commercial protein-based LFD.

The soybean (Glycine max) has been recognized as a frequent elicitor of food allergy worldwide. A lack of causative immunotherapy of soybean allergy makes soybean avoidance essential. Therefore, sensitive and specific methods for soybean detection are needed to allow for soybean verification in foods. Loop-mediated isothermal amplification (LAMP) represents a rapid and simple DNA-based detection method principally suitable for field-like applications or on-site analytical screening for allergens during the manufacturing of foods. This work describes the systematic development and selection of suitable LAMP primers based on soybean multicopy genes. The chemistry applied allows for a versatile detection of amplified DNA, using either gel electrophoresis, fluorescence recording, or a simple Lateral Flow Dipstick (LFD). LAMP based on the ORF160b gene was highly specific for the soybean and may allow for a detection level equivalent to approximately 10 mg soy per kg food. Various soybean cultivars were detectable at a comparable level of sensitivity. LAMP combined with LFD-like detection facilitates a simple, highly specific and sensitive detection of the soybean without the need for expensive analytical equipment. In contrast to the majority of antibody-based methods for soybean detection, all identified primer sequences and optimized protocols are disclosed and broadly available to the community.

Infection with Zika virus (ZIKV) came first to public attention after it was found to be associated with congenital microcephaly during the outbreak in Brazil (2015–2016). Diagnosis of ZIKV suffers from extensive cross-reactivity with other Flaviviruses, which are circulating in many ZIKV epidemic areas. Due to the fatal outcome of ZIKV infection during pregnancy, detailed knowledge about neutralizing and non-neutralizing epitopes is crucial for the development of robust detection systems of protective antibodies. Therefore, additional information about ZIKV immunogenicity and antibody response is required. In this project, we report the production, purification and characterization of six different polyclonal antibodies against ZIKV envelope (E) protein. The produced antibodies bind to isolated ZIKV E protein as well as to the surface of ZIKV particles, interestingly without being potently neutralizing. Surface plasmon resonance measurement showed that these antibodies bind with high affinity to ZIKV E protein. Epitope mapping revealed that the epitopes are distributed among the three ZIKV E domains with seven binding sites. These identified binding sites overlap only partially with the previously described epitopes recognized by neutralizing antibodies, which is in accordance with their lack of potent neutralizing activity. Additionally, these antibodies showed neither cross-reactivity nor potent neutralizing activity against West Nile virus, a related flavivirus. The gained set of data helps to extend our understanding about the distribution of neutralizing and non-/weak-neutralizing epitopes in ZIKV E protein, and provides a rationale for ZIKV vaccine design and development of robust detection assays for neutralizing antibodies.