Molecular Properties and Allergenicity of Lectin from Ulva lactuca

Abstract

Ulva lactuca, the type species of the genus algae, holds ecological significance in coastal ecosystems and has attracted considerable interest in food and medical applications due to its bioactive constituents. Proteins or peptides from algae that exhibit high abundance, stability, or significant homology to specific allergens were identified as antigens by immune cells. In response, the immune system mounts a variable reaction to each protein, ultimately leading to cellular degranulation and the manifestation of a range of diseases. Lectin, derived and purified from Ulva lactuca (U. lactuca), displaying distinct bands at molecular weights of 107.55, 75, 67.6, 35, 32.02, 28.75, 23.51, 18.7, and 10.7 kDa. Subsequent bioinformatic alignment against the PDB database revealed significant homology between U. lactuca lectin and documented allergenic lectins. In vitro evaluation using rat basophilic leukemia mast cells (RBL-2H3) demonstrated that U. lactuca lectin significantly promoted mast cell degranulation, whereas histamine (His) release rate was reached at 45.28 ± 2.40 ng mL-1. In vivo experiments revealed that U. lactuca lectin induced splenomegaly, and promoted substantial elevation of His and mast cell proteases in mice. Moreover, U. lactuca lectin samples exhibited significantly upregulated levels of allergen-specific Immunoglobulin E (IgE), Immunoglobulin G1 (IgG1) inducing a Th2 immune response. These findings provide foundational evidence for the allergenic potential of U. lactuca lectin and contribute to safety evaluations of marine-derived proteins.