{Reference Type}: Journal Article {Title}: Immunological comparison of recombinant shrimp allergen Pen m 4, produced in Pichia pastoris and Escherichia coli. {Author}: Rainyte J;Zvirblis G;Zaveckas M;Kucinskaite-Kodze I;Silimavicius L;Petraityte-Burneikiene R; {Journal}: J Biotechnol {Volume}: 369 {Issue}: 0 {Year}: 2023 Jun 10 {Factor}: 3.595 {DOI}: 10.1016/j.jbiotec.2023.05.002 {Abstract}: Shellfish are a leading cause of allergies worldwide, affecting about one-tenth of the general population. The sarcoplasmic calcium-binding protein, also known as allergen Pen m 4, is an important factor in shrimp allergies. Our objective was to assess the most effective techniques for producing a recombinant Pen m 4 protein as a potential tool for diagnosing shrimp allergies. In this study, for the first time, we produced a functional recombinant Pen m 4 protein in a eukaryotic system, Pichia pastoris, and analyzed it against Escherichia coli-produced equivalents in enzyme-linked immunosorbent and reverse-phase protein microarray assays. A dual tag system based on the maltose-binding protein was successfully used to increase the yield of Pen m 4 by 1.3-2.3-fold in both bacteria and yeast, respectively. Immunological characterization showed that N-glycosylation is neither crucial for the folding of Pen m 4 nor its recognition by specific IgE. However, the Ca2+-depletion assay indicated a dependence on calcium ion presence in blood samples. Results demonstrate how a comparative analysis can elucidate essential allergen manufacturing points. In conclusion, E. coli-produced Pen m 4 protein fused with the maltose-binding protein should be the preferred option for further studies in Penaeus monodon allergy diagnostics.