Involvement of Pacific oyster CgPGRP-S1S in bacterial recognition, agglutination and granulocyte degranulation

Masao Iizuka, Toshihiro Nagasaki, Keisuke G. Takahashi, Makoto Osada, Naoki Endo

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Peptidoglycan recognition protein (PGRP) recognizes invading bacteria through their peptidoglycans (PGN), a component of the bacterial cell wall. Insect PGRPs contribute to effective immune systems as inducers of other host defense responses, while this function has not been reported from PGRP of bivalves. In this study, recombinant CgPGRP-S1S (rCgPGRP-S1S), produced in the mantle and the gill, was synthesized and used to elucidate the immunological function of CgPGRP-S1S. rCgPGRP-S1S bound specifically to DAP-type PGN and to Escherichia coli cells, but not to other DAP-type PGN-containing bacterial species, Vibrio anguillarum, or Bacillus subtilis. Antibacterial activity was not detected, but E. coli cells were agglutinated. Moreover, in addition to these direct interactions with bacterial cells, rCgPGRP-S1S induced secretion of granular contents by hemocyte degranulation. Taken together, these results suggest for the first time that a PGRP of bivalves is, just as in insects, involved in host defense, not only by direct interaction with bacteria, but also by triggering other defense pathways.

Original languageEnglish
Pages (from-to)30-34
Number of pages5
JournalDevelopmental and Comparative Immunology
Issue number1
Publication statusPublished - 2014 Mar


  • Bivalves
  • Granulocyte
  • Hemocyte
  • Immune mediator
  • Pattern recognition
  • Peptidoglycan recognition protein

ASJC Scopus subject areas

  • Immunology
  • Developmental Biology


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