title: The haemocytic origin of lymphoid organ spheroid cells in the penaeid prawn Penaeus monodon.
abstract: Studies on lymphoid organ spheroid (LOS) cells of Penaeus monodon were undertaken. Phenoloxidase and peroxidase assays showed that LOS cells have characteristics similar 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 stromal 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 midcrop mortality syndrome (MCMS) (80 +/- 12%). In conclusion, LOS cells have the characteristics of exocytosed, granular haemocytes that have phagocytosed foreign material, particularly viruses, and probably constitute a major mechanism for penaeid antiviral defense.
authors.affiliation: Department of Microbiology and Immunology, James Cook University, Australia.
authors.forename: M S
authors.initials: MS
authors.lastname: Anggraeni
authors.forename: L
authors.initials: L
authors.lastname: Owens
mesh_terms: D000818:Animals; D017209:Apoptosis; D004156:Catechol Oxidase / Q000378:metabolism; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism; D006434:Hemocytes / Q000166:cytology*; D017403:In Situ Hybridization / Q000662:veterinary; D008221:Lymphoid Tissue / Q000166:cytology*; D033561:Penaeidae / Q000166:cytology*
chemical_list: D004792:Enzyme Precursors; C038451:pro-phenoloxidase; D004156:Catechol Oxidase