Cross-serotype immunity and aspects of virulence in Ichthyophthirius multifiliis
Swennes, Alton Gordon
MetadataShow full item record
The parasitic ciliate Ichthyophthirius multifiliis infects the skin and gill epithelia of freshwater fish. It expresses membrane proteins referred to as immobilization antigens (i-antigens), which define serotypes that are distinguished by antibody immobilization antibodies. Antibody cross-linking of i-antigens confers serotype-specific protection, making it of interest to characterize differences in virulence and mechanisms of cross-immunity between these serotypes. In these studies, it was found that the differences in virulence between isolates are not due to their initial infection rate, but rather to the interaction between their life cycle period and the kinetics of the fish immune response. It was also found that cross-immunity exists between I. multifiliis serotypes, and that this protection did not involve the i-antigens. These studies lay the groundwork for the identification of parasite virulence mechanisms as well as other proteins that could be used in vaccines.