Identification of IgE Epitopes and Analysis of Critical Amino Acid Residues in Fish Parvalbumin

The increasing incidence of fish allergy, primarily triggered by parvalbumin (PV), has become a significant public health issue. Although novel PVs are increasingly being characterized, the allergenic epitopes have not been comprehensively identified. This study aimed to explore the IgE epitopes of PV and identify critical amino acid residues, while systematically assessing their connection to the IgE-binding capacity. PV from common fish species, which remains unstudied, was first characterized using proteomic, genomic, and immunoinformatic methods. β-PV isoforms from 92 fish species were comparatively analyzed with WEBLOGO and Clustal W, followed by epitope prediction with DNAStar Protean system, BepiPred 3.0, and IEDB. Validation was subsequently conducted with indirect competitive ELISA. Critical amino acid residues of epitopes were confirmed with the substitution approach. Sixteen linear B-cell epitopes of PV were identified, and four amino acids were confirmed as the crucial residues. Furthermore, the study revealed that allergenic peptides' distribution and specific residue arrangements govern IgE-binding potency.