Oyster hemocytes express a proline-rich peptide displaying synergistic antimicrobial activity with a defensin

Yannick Gueguen, Romestand Bernard, Fievet Julie, Schmitt Paulina, Destoumieux Garzón Delphine, Vandenbulcke Franck, Bulet Philippe, Bachère Evelyne

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82 Scopus citations


A cDNA sequence that encodes a 61-amino acid polypeptide precursor with homologies to proline-rich antimicrobial peptides (AMPs) was identified in the oyster Crassostrea gigas. After release of a hydrophobic signal peptide, the resulting 37-amino acid peptide, Cg-Prp, is composed of an acidic region and a cationic proline-rich region. To evaluate the biological properties of Cg-Prp, multiple proline-rich peptides corresponding to putative processing of the full-length Cg-Prp were synthesized. A limited antimicrobial activity was observed for two of them, which also showed strong synergistic antimicrobial activity with Cg-Def, a defensin from C. gigas. To our knowledge, this is the first evidence of synergy between a defensin and another AMP in an invertebrate. By in situ hybridization, the expression of Cg-prp was found to be restricted to hemocytes and induced following bacterial challenge. Cg-prp transcripts were also detected in hemocytes infiltrating mantle, where Cg-Def is expressed. Additionally, by immunocytochemistry, we showed that Cg-Prp or one of its variants is present in some hemocytes together with defensins. In conclusion, we described here the first proline-rich AMP from mollusk. From our study, it is likely to provide a first line of defense against bacterial invasion by acting through synergy with defensins.

Original languageEnglish
Pages (from-to)516-522
Number of pages7
JournalMolecular Immunology
Issue number4
StatePublished - Feb 2009
Externally publishedYes


  • Antimicrobial peptide
  • Innate immunity
  • Invertebrate
  • Mollusk
  • Pacific oyster
  • Synergy


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