American Society of Hirudotherapy

Toll-like receptor genes (TLRs) from Capitella capitata and Helobdella robusta (Annelida)

Research article published in Developmental and comparative immunology (2007)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Genomics & ProteomicsDavidson CR et al. · Developmental and comparative immunology, 2007

Abstract

Toll-like receptors (TLRs) are an important part of the innate immunity system and are found throughout the animal kingdom, but have not yet been reported in annelids. We searched shotgun reads of the genomes of the leech Helobdella and polychaete Capitella for TLR homologs. We found 105 TLR homologs in Capitella and 16 in Helobdella. The deduced phylogeny of these sequences, together with TLRs from other animal phyla, reveals three major clades. One clade consists of a mixture of both vertebrates and invertebrates, including sequences from Capitella and Helobdella, while the other two clades contain only invertebrate TLRs.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article
Indexed MeSH termsAnimalsAnnelidaEvolution, MolecularImmunity, InnateParacrine CommunicationPhylogenySequence AlignmentSequence Analysis, DNAToll-Like Receptor 2Toll-Like Receptors

Summary

Toll-like receptors (TLRs) are an important part of the innate immunity system and are found throughout the animal kingdom, but have not yet been reported in annelids.

Why This Matters for Hirudotherapy

This study searched shotgun genome reads of the leech Helobdella and the polychaete Capitella (both Annelida) for Toll-like receptor (TLR) homologs, identifying 16 TLRs in Helobdella and 105 in Capitella, and deducing a phylogeny with three major clades including one mixed vertebrate/invertebrate clade. Because Helobdella is described in the abstract as a leech, the work provides molecular data on innate immune gene diversity within an annelid leech, which is tangentially relevant to leech biology. However, the study is purely molecular/phylogenetic, involves no secretome, hirudotherapy, or bioactive salivary compounds, and the abstract does not address therapeutic relevance, so its practical relevance to hirudotherapy is limited and indirect.

Citation

Toll-like receptor genes (TLRs) from Capitella capitata and Helobdella robusta (Annelida)

Davidson CR et al. · Developmental and comparative immunology, 2007

DOI

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