Normal snapper (Pagrus auratus Bloch and Schneider) serum was examined for natural IgM that binds to protease (bromelain) treated sheep erythrocytes (BrSRBC) in a model assay system that has been used to appraise natural IgM of various mammals. Normal snapper serum lysed BrSRBC while haemolysis was abrogated by heat inactivation of serum and in divalent cation-deficient conditions, indicative of classical complement mediated lysis. In addition, heat inactivated normal snapper serum agglutinated BrSRBC while phosphatidylcholine (PtC) liposomes partially inhibited both haemolysis and agglutination. Inhibition of haemolysis and agglutination may have been mediated by an interaction between immunoglobulin (Ig) and PtC as protein A purified snapper Ig bound to PtC liposomes. However it is not known if this binding was PtC specific nor if the binding was initiated by either the Fab and/or Fc domains of snapper Ig. BrSRBC plaque forming cells (PFC) were detected in the peritoneal cavity, spleen, head kidney and peripheral blood of normal snapper. The greatest proportion of BrSRBC PFC per B cell was within the peritoneal cavity followed by the spleen, peripheral blood and head kidney. Together, these data suggest that normal snapper serum may contain natural Ig that binds BrSRBC, activating the classical complement cascade. © 2004 Elsevier Ltd. All rights reserved.

Item Type:	Refereed Article
Research Division:	Agricultural and Veterinary Sciences
Research Group:	Fisheries Sciences
Research Field:	Aquaculture
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Fisheries - Aquaculture
Objective Field:	Fisheries - Aquaculture not elsewhere classified
UTAS Author:	Morrison, RN (Dr Richard Morrison)
UTAS Author:	Nowak, BF (Professor Barbara Nowak)
ID Code:	32831
Year Published:	2005
Web of Science® Times Cited:	4
Deposited By:	TAFI - Aquaculture
Deposited On:	2005-08-01
Last Modified:	2011-12-06
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