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LitCTL1: A novel C-type lectin involved in the mucosal and cellular immunity of the common periwinkle Littorinalittorea.

Alexander M Gorbushin·Elena A Borisova
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Abstract

C-type lectins (CTLs) are vital pattern-recognition receptors (PRRs) that mediate innate immune responses in mollusks, yet their characterization in Caenogastropoda, the largest gastropod group, remains limited. This study characterizes LitCTL1, a novel secreted single-domain C-type lectin from the common periwinkle, Littorina littorea. The 199-amino acid polypeptide contains a conserved carbohydrate recognition domain with canonical QPD and WND motifs and is predicted to form a homodimer. Uniquely, LitCTL1 was localized in both circulating hemocytes and mucus-secreting epithelial cells of the foot, mantle, and hypobranchial gland - the first report of such dual localization for a molluscan lectin, linking systemic and mucosal defense. Expression analysis revealed that LitCTL1 is constitutively expressed in hemocytes. Functional assays with recombinant LitCTL1 demonstrated its role as a potent opsonin with hemagglutinating activity, significantly enhancing hemocyte spreading and the phagocytosis of zymosan. Genomic analysis reveals that LitCTL1 belongs to a rapidly diversifying, genus-specific expansion distinct from conserved perlucin-like lineages. These results identify LitCTL1 as a key effector molecule in both systemic and mucosal innate immunity, likely reflecting an evolutionary adaptation to the microbial challenges of the intertidal environment.

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AnimalsLectins, C-TypeAmino Acid SequenceSequence AlignmentPhylogenyImmunity, CellularImmunity, MucosalHemocytesGene Expression RegulationSnailsGene Expression ProfilingInnate Immunity RecognitionImmunity, InnateBase SequenceGastropodaInnate immunityInvertebratesMolluscaPattern-recognition receptorsPichia pastoris expression systemJournal Article

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Alexander M Gorbushin, Elena A Borisova. 2026-08-05. LitCTL1: A novel C-type lectin involved in the mucosal and cellular immunity of the common periwinkle Littorinalittorea.. https://doi.org/10.1016/j.fsi.2026.111622

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Journal Article resourceAmino Acid Sequence subjectAnimals subjectGastropoda subjectGene Expression Profiling subjectGene Expression Regulation subjectImmunity, Cellular subjectImmunity, Innate subjectJournal Article subjectinnate immunity subject

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