title: Involvement of Pacific oyster CgPGRP-S1S in bacterial recognition, agglutination and granulocyte degranulation.
abstract: 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.
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiya-machi, Aoba-ku, Sendai, Miyagi 981-8555, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Iizuka
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiya-machi, Aoba-ku, Sendai, Miyagi 981-8555, Japan; Laboratory of Molecular Marine Biology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nagasaki
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiya-machi, Aoba-ku, Sendai, Miyagi 981-8555, Japan.
authors.forename: Keisuke G
authors.initials: KG
authors.lastname: Takahashi
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiya-machi, Aoba-ku, Sendai, Miyagi 981-8555, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Osada
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiya-machi, Aoba-ku, Sendai, Miyagi 981-8555, Japan. Electronic address: nitoh@bios.tohoku.ac.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Itoh
mesh_terms: D000371:Agglutination; D000818:Animals; D001412:Bacillus subtilis / Q000276:immunology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D015550:Cell Degranulation; D002478:Cells, Cultured; D004926:Escherichia coli / Q000276:immunology*; D005880:Gills / Q000378:metabolism*; D006098:Granulocytes / Q000276:immunology*; D006434:Hemocytes / Q000276:immunology*; D007113:Immunity, Innate; D010125:Ostreidae / Q000276:immunology*; D010457:Peptidoglycan / Q000378:metabolism*; D011485:Protein Binding; D051192:Receptors, Pattern Recognition / Q000235:genetics / Q000378:metabolism*; D019076:Transgenes / Q000235:genetics; D014733:Vibrio / Q000276:immunology*
chemical_list: D002352:Carrier Proteins; D010457:Peptidoglycan; D051192:Receptors, Pattern Recognition; C118897:peptidoglycan recognition protein
keywords: Bivalves; Granulocyte; Hemocyte; Immune mediator; Pattern recognition; Peptidoglycan recognition protein