Pancreas disease in Atlantic salmon: serum neutralisation and passive immunisation

Antisera raised in fish following experimental infection with pancreas disease either by intraperitoneal injection of infective kidney homogenate or by cohabitation with infected fish was found to give up to 100% neutralisation when incubated with PD infective kidney homogenate and then injected into fish. Complete neutralisation occurred with antisera obtained four, eight and 15 weeks after infection by injection and eight and 15 weeks after infection by cohabitation. When antisera, taken from fish eight weeks following infection by injection, was diluted up to 1:100, 100% neutralisation occurred. Significant levels of neutralisation still occurred at a 1:1000 dilution. Following passive immunisation of Atlantic salmon parr and post-smolts with week 8 antisera either one, two or three days before or at the same time as or one, two or three days after an i.p. injection of pancreas disease infective kidney homogenate, fish were 100% protected against the disease.