Allergenic activity of Molicola horridus (Cestoda, Trypanorhyncha), a cosmopolitan fish parasite, in a mouse model

The cestode Molicola horridus is a muscle parasite of teleost fish. The ability of molecules present in this parasite to induce allergic response is not known yet. Since fish-borne parasitic allergens can induce allergic manifestations even when the parasitized fish is well cooked, the knowledge of potential allergens present in food is important in order to provide a save products for consumers. The aim of the study was to determine the allergenic potential of the components present in the crude larval extract (CLE) of M. horridus. Two mouse models were exposed to the CLE: adult BALB/c mice that were intraperitoneally (i.p.) immunized and newborn BALB/c mice that were orally exposed. Specific antibody levels in serum and faeces were measured by ELISA. The cellular immune response was determined by proliferation assay of splenocytes from sensitized mice. The protein profile of CLE was analysed by SDS-PAGE and western blot. In adult mice, specific IgG and IgA were detected in sera and faeces, whereas specific IgE were detected in sera only. In newborn mice, specific IgG were detected in sera and a low level of IgA was detected in faeces. SDS-PAGE revealed the CLE protein profile, with most of the proteins running from 15 to 50 kDa. Specific IgG recognized mainly the 26 and 75 kDa proteins and a molecular complex below 100 kDa by immunoblot. Specific IgE recognized the same 26 kDa protein as IgG did, and, with less intensity, another protein at 30 kDa. Splenocytes from CLE-immunized mice proliferated when stimulated with CLE in a dose-dependent manner. The crude larval extract from M. horridus has potential allergenic molecules which can represent a risk for fish consumers.