“…However, protection against furunculosis in fry from vaccinated mothers has also been reported in a salmonid species, the white-spotted char (Salvelinus leocomaenis), by Kawahara et al (1993). A possible explanation for this discrepancy might be that resistance against the bacterial infection yersiniosis requires relatively high levels of antibodies against the lipopolysaccharides (LPS), which are the protective antigens (Amend et al, 1983). Moreover, in addition to antibodies against LPS, contributions from other components of the immune system, in particular the phagocytic system, are probably necessary in order to inactivate Y. ruckeri.…”