The haemocytic origin of lymphoid organ spheroid cells in the penaeid prawn Penaeus monodon

Abstract

Studies on lymphoid organ spheroid (LOS) cells of Penaeus rnonodon were undertaken. Phenoloxidase and peroxidase assays showed that LOS cells have characteristics simllar to semi-granular and, in particular, large granular haemocytes. The mean percentage of LOS cells positive for phenoloxidase and peroxidase was 85 + 23 and 82 * 23%, respectively. There was no significant difference between the sites of phenoloxidase and peroxidase activity in LOS cells ( t = 1.617, df = 29, p > 0.05). The relative sectional area occupied by LOS cells relative to that of the strornal matrix cells from both laboratory-held and farmed prawns was not correlated to increasing weight or total length of the prawns (p > 0.05). An apoptosis detection assay showed that LOS cells were often apoptotic whilst stromal matrix cells were not. There was a significant difference (t = -5.533, df = 58, p < 0.05) in the mean percentage of apoptotic spheroid cells between laboratory-held prawns (52 * 24 % ) and farmed prawns with rnidcrop mortality syndrome (MCMS) (80 i 12%). In conclusion, LOS cells have the chdracteristics of exocytosed, granular haemocytes that have phagocytosed foreign material, particularly viruses, and probably constitute a major mechanism for penaeid antiviral defense.

Detection of gill-associated virus (GAV) by in situ hybridization during acute and chronic infections of Penaeus monodon and P. esculentus

“…GAV was detected in cells lining the sub-gastric artery and tubule lumen within the lymphoid organ. As haemolymph first enters the lymphoid organ via the subgastric artery and must pass through the thin layer of endothelial cells lining the lumen before entering the stromal matrix of the tubules (Oka 1969, Martin et al 1987, Anggraeni & Owens 2000, this may be indicative of an early stage of infection in the lymphoid organ. Tang et al (2002) also reported no loss of normal tubule structure in GAV-infected Litopenaeus vannamei which, like P. esculentus, is not a natural host of GAV.…”

Preliminary study on haemocyte response to white spot syndrome virus infection in black tiger shrimp Penaeus monodon

“…Spheroid development has been described in Taura syndrome virus infections (Hasson et al 1999a,b) and is often associated with other viral infections (Anggraeni & Owens 2000).…”

DNA fragmentation, an indicator of apoptosis, in cultured black tiger shrimp Penaeus monodon infected with white spot syndrome virus (WSSV)

“…The results obtained here suggest that the TUNEL assay may also be an indicator of apoptosis in crustaceans. Indeed, Anggraeni & Owens (2000), in another study, have used TUNEL-positive staining as evidence for apoptosis in lymphoid organ cells of Penaeus monodon infected with a virus.…”