Antibody response of carp, Cyprinus carpio to the cestode, Bothriocephalusacheilognathi

The humoral antibody response and the number of pronephric antibody-secreti ng cells were examined in naturally Bothriocephalus acheilognathi-infected carp. Cyprinus carpio, and in those injected intraperitoneally with an extr act of the cestode. In the extract-injected fish, specific antibody was det ected 3 weeks after a second injection given 2 weeks after the primary inje ction, and antibody levels persisted for more than 200 days. A third inject ion also enhanced the antibody level in the extract-injected carp. The numb ers of antibody-secreting cells were significantly higher in carp injected 3 times with the extract than in the control. In naturally-infected fish, t he serum antibody levels and the number of pronephric antibody-secreting ce lls were higher in infected fish than in uninfected individuals although th is difference was not statistically significant. The relevance of these res ults to immune protection against infection is discussed.