Effect of Cymothoa eremita (Isopoda, Cymothoidae) infection in Oreochromis mossambicus: Immune gene expression and innate immune responses

Abstract

Abstract The host immune response of Oreochromis mossambicus during natural infection with the isopod Cymothoa eremita was investigated. The naturally infected fishes were examined for enzyme profile (Respiratory burst and Myeloperoxidase activity) and expression of immune-related genes viz., TLR 22, C3, TNF, TNF, IL-1B, CXCA and B-actin in tissues of various organs (buccal cavity, gills and anterior kidney). A significant reduction (P < 0.05) in Respiratory burst and Myeloperoxidase activity was observed in the parasite-infected fishes when compared to the uninfected control fishes. In the buccal cavity, the expression of the immune-related genes was significantly (P < 0.05) upregulated. Whereas, all the genes except IL-B were significantly (P < 0.05) upregulated in the anterior kidney. In the case of gill tissue, the expressed genes showed a fluctuating type of regulation. The immunological responses in O. mossambicus to an isopod infection have not been investigated in detail so far and this is the first study unveiling such insights. Hence this study will help to improve our molecular understanding of the host immune response to parasitic isopod infection.