Ostreid Herpesvirus-1 Infects Specific Hemocytes in Ark Clam, Scapharca broughtonii

Abstract

High levels of ostreid herpesvirus 1 (OsHV-1) were detected in hemocytes of OsHV-1 infected mollusks. Mollusk hemocytes are comprised of different cell types with morphological and functional heterogeneity. Granular cells are considered the main immunocompetent hemocytes. This study aimed to ascertain if OsHV-1 infects specific types of hemocytes in ark clams. Types of hemocytes were first characterized through microexamination and flow cytometry. In addition to a large group of red cells, there were three types of recognizable granular cells in ark clams. Type II granular cells were mostly found with OsHV-1 infection by transmission electron microscope (TEM) examination, and represented the hemocyte type that was susceptible to OsHV-1 infection. The subcellular location of OsHV-1 particles in apoptotic type II granular cells was further analyzed. Some OsHV-1 particles were free inside the apoptotic cells, which may contribute to OsHV-1 transmission among cells in the host, some particles were also found enclosed inside apoptotic bodies. Apoptosis is an important part of the host defense system, but might also be hijacked by OsHV-1 as a strategy to escape host immune attack. Following this investigation, a primary culture of type II granular cells with OsHV-1 infection would facilitate the research on the interaction between OsHV-1 and mollusk hosts.

Type II Grass Carp Reovirus Infects Leukocytes but Not Erythrocytes and Thrombocytes in Grass Carp (Ctenopharyngodon idella)

“…Blood cells act as the primary executors of cellular immune defense [ 45 ], which is a major target cell for Oyster herpesvirus (OsHV-1) and white spot syndrome virus (WSSV) [ 46 , 47 ]. Semigranular cells and granulosa cells are two types of host cells specifically targeted by WSSV in shrimp.…”

Characterization of Host Cell Potential Proteins Interacting with OsHV-1 Membrane Proteins

“…Tens of putative membrane proteins are encoded in the OsHV-1 genome, which may endow OsHV-1 with multiple tissue tropism. OsHV-1 particles had been observed in the mantle cells and hemocytes of infected ark clams and oyster spats by transmission electron microscope or in situ hybridization [22,23]. There should be diverse entry receptors in host cells for OsHV-1 resembling the corresponding hosts of other herpesviruses.…”

Detection of Perkinsus marinus in a wild population of the horsemussel Modiolus capax from the southwestern Gulf of California

“…Entre los parásitos más importantes que se han reportado en moluscos bivalvos del Golfo de California destacan el virus OsHV-1 y los protozoarios Marteilia refringens (Grizel, Comps, Bonami, Cousserans, Duthoit & Le Pennec, 1974) y Perkinsus marinus [(Mackin, Owen & Collier) Levine, 1978], los cuales, han sido encontrados en las almejas Ruditapes philippinarum (Adams & Reeve, 1850) (Renault et al, 2001) y Scapharca broughtonii (Adams & Reeve, 1850) (Xin et al, 2018), y en los ostiones Magallana (≈Crassostrea) gigas (Thunberg, 1973) y Crassostrea corteziensis (Hertlein, 1951) (Cáceres-Martínez et al, 2008Grijalva-Chon et al, 2013Enríquez-Espinoza et al, 2015). Específicamente para P. marinus, desde que se comprobó su transfaunación de las costas del Océano Atlántico (Bushek & Allen, 1996;Reece et al, 2008;Cáceres-Martínez et al, 2016) y, posteriormente, se confirmó su presencia en las costas del Pacífico Mexicano (Cáceres-Martínez et al, 2008;Ek-Huchim et al, 2017), este protozoario ha sido detectado en ostiones cultivados, fuera (Cáceres-Martínez et al, 2008) y dentro (Cáceres-Martínez et al, 2018) del Golfo de California, sin afectar su producción (Villanueva-Fonseca & Escobedo-Bonilla, 2013;Martínez-García et al, 2017;Villanueva-Fonseca et al, 2020); aunque también, se ha reportado asociado a mortalidades de ostreidos (Enríquez-Espinoza et al, 2010).…”