Humoral immune responses induced by Kudoa sp. (Myxosporea: Multivalvulida) in BALB/c mice: oral administration, immunization and cross-reactions with Myxobolus aeglefini (Myxosporea: Bivalvulida).

The majority of Kudoa species infect the somatic muscle of fish, establishing cysts. Because there is no effective method to detect infected fish without destroying them, these parasitized fish reach the consumer. The elevated humoral responses detected previously by us in BALB/c mice immunized with Kudoa sp. pseudocyst extracts showed the possible immunopathological effects in man from the ingestion of Kudoa-infected fish. In this work, the high IgG1 and IgE levels induced by the oral administration of Kudoa pseudocysts to BALB/c mice confirmed the allergenic nature of some of their components. An alternative way of preparing the soluble extract by using a FastPrep' shaker indicated the inconvenience of using sonication to prepare the Kudoa sp. extract. IgG+M, IgG, IgG3 and IgA cross-reactions of Kudoa sp. with another myxosporean, Myxobolus aeglefini, were found.