Transcriptional analysis of the common carp (Cyprinus carpio L.) immune response to the fish louse Argulus japonicus Thiele (Crustacea: Branchiura).

In the present study we investigated changes in transcription levels of a panel of selected immune relevant genes in peripheral blood leucocytes (PBL) and skin samples collected from carp exposed to larval Argulus japonicus. We show that in skin up-regulation of gene transcription of the chemokine CXCa, and to a lesser extent the chemokine receptor CXCR1 and the cytokine TNFalpha, are good indicators of parasite-induced skin damage at 2 days post-parasite exposure. Up-regulation of gene transcription corresponded well with an increase in leucocytes, probably neutrophilic granulocyte numbers in skin samples collected at the sites of infection.

Differential macrophage polarisation during parasitic infections in common carp (Cyprinus carpio L.).

In many parasitic infections both classically activated macrophages (caMF) and alternatively activated macrophages (aaMF) play a pivotal role. To investigate if both types of macrophages also play an important role during parasitic infections in fish, we infected carp with either Trypanoplasma borreli or Trypanosoma carassii and determined the activation state of the head kidney leukocytes (HKL). Nitrite production was used as read-out for caMF and arginase activity as read-out for aaMF.

The immune response of carp to Trypanoplasma borreli: kinetics of immune gene expression and polyclonal lymphocyte activation.

Although Trypanoplasma borreli induces the production of non-specific antibodies, survival of infection is associated with the production of T. borreli specific antibodies, able to lyse this parasite in the presence of complement. During the lag phase of this acquired immune response, innate immune mechanisms must limit multiplication of T.