Characterization of 2S albumin allergenic proteins for anaphylaxis in common buckwheat

Establishment of monoclonal antibodies of BW10kDa distinguish it from Fag e 2 related to anaphylaxis

BW10kDa, which is a buckwheat (BW) allergen, belongs to the 2S-albumin protein family, akin to Fag e 2. Detailed analyses of BW10kDa were lacking until this study. Herein, we conducted these analyses using monoclonal antibodies (mAbs) to recombinant BW10kDa (rBW10kDa). We successfully generated anti-rBW10kDa mAbs capable of distinguishing between Fag e 2 and BW10kDa. These mAbs were categorised into two types (type 1 and type 2) based on their reactivity to BW plant seed extracts in western blot analyses. Type 1 mAbs revealed two bands (15 kDa and 10 kDa), while type 2 mAbs showed a single band (15 kDa). Spot analyses using these mAbs confirmed that type 1 mAbs recognised epitopes near the C-terminal region, with the 10 kDa band representing the C-terminal subunit cleaved by protease. The mAbs targeting rBW10kDa enabled to assess the concentration of BW10kDa in wild type and also in diagnostic buckwheat extracts.

Elimination of zero-repeat subunit in allergenic seed protein 13S globulin using the novel allele GlbNB2 in common buckwheat (Fagopyrum esculentum Moench)

Common buckwheat (Fagopyrum esculentum Moench) seeds contain 13S globulin, the zero-repeat subunit of which is trypsin-resistant and allergenic. Here, its two novel alleles were analyzed for development of hypoallergenic plants. The GlbNC allele has a Miniature Inverted-repeat Transposable Element (MITE)-like insertion in the 4th exon. However, most of the insertion was spliced-out, resulting in accumulation of zero-repeat subunit in GlbNC homozygotes. Meanwhile, the GlbNB2 has a 164-bp insertion in the 3rd exon, resulting in no accumulation of zero-repeat subunit in GlbNB2 homozygotes (NB2_homo). Both the insertion sequences were predicted to form a hairpin-like structure, and that of GlbNB2 was more rigid than that of GlbNC. Trypsin digestion in NB2_homo showed that the α polypeptide of Met-rich subunit is also hard to digest, that is a next target to eliminate for hypoallergenic buckwheat development.

Emerging and Novel Elicitors of Anaphylaxis: Collegium Internationale Allergologicum Update 2024

BACKGROUND

Anaphylaxis represents the most severe end of the spectrum of allergic reactions. Frequent elicitors of anaphylaxis are insects, foods, and drugs. This paper summarizes recent development with regard to emerging and novel elicitors of anaphylaxis.

SUMMARY

Food allergens on the rise include pulses (like pea, chickpea), seeds (hemp, chia), nuts (cashew), pseudograins (buckwheat, quinoa), fruits, and microalgae. Novel foods are foods that were not consumed to any significant extent in the European Union before May 1997, which includes four edible insects (mealworm, migratory locust, house cricket, and buffalo worm). Recent investigations have pointed out the risk of anaphylaxis associated with the consumption of yellow mealworm for people allergic to shellfish and house dust mites. In Europe, fire ants (mostly Solenopsis invicta) and Vespa velutina nigrithorax represent invasive species, which account for increasing numbers of anaphylactic reactions. Also, several new drugs, especially biologicals, have been associated with anaphylaxis.

KEY MESSAGES

Elicitors of anaphylaxis are changing as a result of (i) increase in demand for plant-based food, (ii) introduction of novel foods, (iii) spreading of allergens by climate changes and globalization, or (iv) due to exposure to newly developed drugs.

Study on the reduction of Tartary buckwheat allergenicity during Pediococcus pentosaceus fermentation by HPLC-MS/MS analysis

Tartary buckwheat contains more valuable nutrients than common buckwheat, but it also contains allergenic proteins that induce allergic reactions through an IgE-mediated response. Our study demonstrated that fermentation by Pediococcus pentosaceus degrades allergenic proteins in Tartary buckwheat, as confirmed by HPLC-MS/MS analysis of polypeptides. Our results showed significant degradation of the protein after 16 h of Pediococcus pentosaceus fermentation (PP16), leading to a reduction in IgE-binding activity. Comparison with unfermented Tartary buckwheat (UTB) peptides yielded 2042 fragments, of which 756 fragments associated with allergenic proteins were upregulated. Among them, the expression of 213 fragments was reduced by 71.83%. By performing bioactivity prediction on potential allergenic peptide fragments, we identified six peptide fragments derived from Fagt 1, potentially contributing to the residual allergenicity in PP16. These suggest that Pediococcus pentosaceus fermentation can effectively destroy allergen epitopes and mitigate the allergenicity of Tartary buckwheat.

Insertion of ten amino acids into 13S globulin zero-repeat subunit improves trypsin digestibility in common buckwheat (Fagopyrum esculentum Moench) seeds

The 13S globulin zero-repeat subunit is resistant to trypsin and may have higher allergenicity than the 1-6 tandem repeat subunits in common buckwheat (Fagopyrum esculentum Moench). To explore alleles useful for lowering allergenicity, amplicon deep sequencing targeting the zero-repeat subunit gene was conducted in bulked genomic DNA from eight cultivars and landraces. The analysis identified a unique allele encoding a zero-repeat subunit with 10 amino acid insertion (10aa) at a position equivalent to the tandem repeat insertion. Prediction of its 3-D structure suggested that 10aa changes the β-hairpin structure in the non-10aa (native) subunit to a random coil, which is also found in 1- and 3- repeat subunits. Homozygotes of the 10aa allele were developed and showed that the 10aa subunit was more digestible than the native subunit. However, the 10aa subunit was still less digestible than the 1-6 repeat subunits, suggesting needs to explore unfunctional alleles.