title: Galectin CvGal2 from the Eastern Oyster (Crassostrea virginica) Displays Unique Specificity for ABH Blood Group Oligosaccharides and Differentially Recognizes Sympatric Perkinsus Species.
abstract: Galectins are highly conserved lectins that are key to multiple biological functions, including pathogen recognition and regulation of immune responses. We previously reported that CvGal1, a galectin expressed in phagocytic cells (hemocytes) of the eastern oyster (Crassostrea virginica), is hijacked by the parasite Perkinsus marinus to enter the host, where it causes systemic infection and death. Screening of an oyster hemocyte cDNA library revealed a novel galectin, which we designated CvGal2, with four tandemly arrayed carbohydrate recognition domains (CRDs). Phylogentic analysis of the CvGal2 CRDs suggests close relationships with homologous CRDs from CvGal1. Glycan array analysis, however, revealed that, unlike CvGal1 which preferentially binds to the blood group A tetrasaccharide, CvGal2 recognizes both blood group A and B tetrasaccharides and related structures, suggesting that CvGal2 has broader binding specificity. Furthermore, SPR analysis demonstrated significant differences in the binding kinetics of CvGal1 and CvGal2, and structural modeling revealed substantial differences in their interactions with the oligosaccharide ligands. CvGal2 is homogeneously distributed in the hemocyte cytoplasm, is released to the extracellular space, and binds to the hemocyte surface. CvGal2 binds to P. marinus trophozoites in a dose-dependent and β-galactoside-specific manner. Strikingly, negligible binding of CvGal2 was observed for Perkinsus chesapeaki, a sympatric parasite species mostly prevalent in the clams Mya arenaria and Macoma balthica. The differential recognition of Perkinsus species by the oyster galectins is consistent with their relative prevalence in oyster and clam species and supports their role in facilitating parasite entry and infectivity in a host-preferential manner.
authors.affiliation: †Department of Microbiology and Immunology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Columbus Center, 701 East Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Chiguang
authors.initials: C
authors.lastname: Feng
authors.forename: Anita
authors.initials: A
authors.lastname: Ghosh
authors.forename: Mohammed N
authors.initials: MN
authors.lastname: Amin
authors.affiliation: ∥University of Maryland Center for Environmental Science and Institute of Marine and Environmental Technology, Columbus Center, 701 East Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Tsvetan R
authors.initials: TR
authors.lastname: Bachvaroff
authors.affiliation: †Department of Microbiology and Immunology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Columbus Center, 701 East Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tasumi
authors.affiliation: †Department of Microbiology and Immunology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Columbus Center, 701 East Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Marta
authors.initials: M
authors.lastname: Pasek
authors.affiliation: †Department of Microbiology and Immunology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Columbus Center, 701 East Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Aditi
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: †Department of Microbiology and Immunology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Columbus Center, 701 East Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Surekha
authors.initials: S
authors.lastname: Shridhar
authors.forename: Lai-Xi
authors.initials: LX
authors.lastname: Wang
authors.forename: Mario A
authors.initials: MA
authors.lastname: Bianchet
authors.affiliation: †Department of Microbiology and Immunology, University of Maryland School of Medicine and Institute of Marine and Environmental Technology, Columbus Center, 701 East Pratt Street, Baltimore, Maryland 21202, United States.
authors.forename: Gerardo R
authors.initials: GR
authors.lastname: Vasta
mesh_terms: D056893:Alveolata / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001789:Blood Group Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D049896:Crassostrea / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000469:parasitology; D037161:Galectins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006434:Hemocytes / Q000737:chemistry / Q000378:metabolism / Q000469:parasitology; D009844:Oligosaccharides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny
chemical_list: D001789:Blood Group Antigens; D037161:Galectins; D009844:Oligosaccharides