Humoral response of captive zebra sharks Stegostoma fasciatum to salivary gland proteins of the leech Branchellion torpedinis
Research article published in Fish & shellfish immunology (2012)
Abstract
Parasitism by the marine leech Branchellion torpedinis is known to cause disease and mortality in captive elasmobranchs and is difficult to control when inadvertently introduced into public aquaria. Preliminary characterization of the salivary gland transcriptome of B. torpedinis has identified anticoagulants, proteases, and immunomodulators that may be secreted into host tissues to aid leech feeding. This retrospective study examined antigen-specific serum IgM responses in captive zebra sharks Stegostoma fasciatum to leech salivary gland extract. Antibody response was examined by ELISA and Western blot assays in 20 serum samples from six zebra sharks, with a 5 year history of leech infection, and 18 serum samples from 8 captive bred zebra sharks, with no history of leech exposure. ELISA demonstrated significantly higher serum IgM titers to salivary gland extract in exposed zebra sharks compared to the non-exposed population. No obvious trends in antibody titers were appreciated in exposed zebra sharks over a four-year period. One-dimensional and two-dimensional Western blot assays revealed IgM targeted specific salivary gland proteins within the 40, 55, 70 and 90 kD range. Antigenic proteins identified by liquid chromatography-tandem mass spectrometry and de novo peptide sequencing include a secreted disintegrin, metalloproteinase and thrombospondin motif containing protein (ADAMTS), tubulin, aldehyde dehydrogenase and two unknown proteins. Humoral immune responses to leech salivary gland proteins warrants further investigation as there may be options to exploit immune mechanisms to reduce parasite burdens in aquaria.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
Parasitism by the marine leech Branchellion torpedinis is known to cause disease and mortality in captive elasmobranchs and is difficult to control when inadvertently introduced into public aquaria.
Why This Matters for Hirudotherapy
This retrospective study measured antigen-specific serum IgM in captive zebra sharks against salivary-gland extract from the marine leech Branchellion torpedinis, finding significantly higher antibody titers in leech-exposed sharks than in unexposed ones, with IgM targeting specific salivary proteins (40-90 kD) identified by mass spectrometry as including an ADAMTS-type secreted protein. For the hirudotherapy and leech-secretome story, it is a useful reminder that leech salivary glands are a complex source of anticoagulants, proteases, and immunomodulators that provoke a measurable host immune response, and it adds to the catalog of characterized leech-derived proteins. The caveat is that this is an observational immunology study in an aquarium fish species aimed at controlling parasitic leech burden, not a therapeutic study of medicinal-leech (Hirudo) therapy in humans, so its relevance is mechanistic and contextual rather than clinical.
Citation
Humoral response of captive zebra sharks Stegostoma fasciatum to salivary gland proteins of the leech Branchellion torpedinis
Marancik DP et al. · Fish & shellfish immunology, 2012
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