Two Distinct Interferon-γ in the Orange-Spotted Grouper (Epinephelus coioides): Molecular Cloning, Functional Characterization, and Regulation in Toll-Like Receptor Pathway by Induction of miR-146a.

Interferon gamma (IFNγ) is a Th1 cytokine that is critical for innate and adaptive immunity. Toll-like receptors (TLRs) signaling pathways are critical in early host defense against invading pathogens. miR-146a has been reported to participate in the regulation of host immunity. The known mechanisms of integrations between the IFNγ and TLR signaling pathways are incompletely understood, especially in teleosts. In this study, orange-spotted grouper (Epinephelus coioides) IFNγ1 and IFNγ2, their biological activities, especially their involvements in TLR pathway, were explored. We identified and cloned two IFNγ genes of E. coioides, namely EcIFNγ1 and EcIFNγ2. The produced recombinant E. coioides IFNγ1 (rEcIFNγ1) and IFNγ2 (rEcIFNγ2) proteins showed functions, which are similar to those of other bony fishes, such as enhancing nitric oxide responses and respiratory burst response. rEcIFNγ2 could regulate TLR pathway by enhancing the promoter activity of miR-146a upstream sequence and thus increasing the expression level of miR-146a, which possibly targets TNF receptor-associated factor 6 (TRAF6), a key adapter molecule in TLR signaling pathway. Taken together, these findings unravel a novel regulatory mechanism of anti-inflammatory response by IFNγ2, which could mediate TLR pathway through IFNγ2-miR-146a-TRAF6 negative regulation loop. It is suggested that IFNγ2 may provide a promising therapeutic, which may help to fine tune the immune response.

Tetraodon nigroviridis: A model of Vibrio parahaemolyticus infection.

Vibriosis is the most common bacterial diseases and brings great economic loss on aquaculture. Vibrio parahaemolyticus (V. parahaemolyticus), a gram-negative bacterium, has been identified as one main pathogens of Vibriosis. The pathogenic mechanism of V. parahaemolyticus is not entirely clear now. In our study, a model of V. parahaemolyticus infection of green-spotted puffer fish (Tetraodon nigroviridis) was established. T. nigroviridis were injected intraperitoneally (i.p.) with 200 µL of V. parahaemolyticus (8 × 10(10) CFU/mL). V. parahaemolyticus infection caused 64% mortality and infected some organs of T. nigroviridis. Histopathology studies revealed V. parahaemolyticus infection induced tissue structural changes, including adipose hollow space in the liver. Immunohistochemistry showed V. parahaemolyticus were present in infected tissue such as liver, head kidney and spleen. In livers of T. nigroviridis infected by V. parahaemolyticus, the alkaline phosphatases (ALP) activity first gradually increased and then backed to normal level, a trend that was on the contrary to the expression profile of the miR-29b. Quantitative real-time PCR analysis showed that the expression level of TLR1, TLR2, TLR5, TLR9, TLR21, NOD1, NOD2 and IL-6 in response to V. parahaemolyticus infection decreased compared to that of non-infected fish. The establishment of the T. nigroviridis model of V. parahaemolyticus infection further confirmed V. parahaemolyticus spreads through the blood circulation system primary as an extracellular pathogen. Meanwhile, liver is an important target organ when infected by V. parahaemolyticus. miR-29b in liver was involved in the progress of liver steatosis during V. parahaemolyticus infection. Moreover, V. parahaemolyticus infection in vivo may have an effect of immunosuppression on host.

Two distinct interferon-γ genes in Tetraodon nigroviridis: Functional analysis during Vibrio parahaemolyticus infection.

Interferon gamma (IFNγ) is a Th1 cytokine that plays a very important role in almost all phases of immune and inflammatory responses. In this study, we explored the functions of IFNγ1 and IFNγ2 of Tetraodon nigroviridis. Treating T. nigroviridis spleen and head kidney cells in vitro with recombinant T. nigroviridis IFNγ1 protein (rTn IFNγ1) or recombinant T. nigroviridis IFNγ2 protein (rTn IFNγ2) enhanced their nitric oxide responses. Both rTn IFNγ1 and rTn IFNγ2 also induced the expression of interferon-stimulated gene 15 (ISG15), a common anti-viral gene, although the expression of the interferon-inducible Mx gene was markedly inhibited by rTn IFNγ1 and was induced by rTn IFNγ2. The in vivo effects of rTn IFNγ1 and rTn IFNγ2 on Vibrio parahaemolyticus (V. parahaemolyticus) infection were assessed by intraperitoneally injecting rTn IFNγ1 or rTn IFNγ2 (100 ng) and V. parahaemolyticus (8 × 10(10)CFU/mL) into T. nigroviridis. A comparison of the group treated only with V. parahaemolyticus and those also treated with rTn IFNγ1 or rTn IFNγ2 showed that neither of these IFNγs protected T. nigroviridis from V. parahaemolyticus infection. However, rTn IFNγ1 more rapidly and robustly promoted inflammatory responses compared with rTn IFNγ2, whereas rTn IFNγ2 was involved in inducing the host to develop a more effective response earlier during the later stage of a V. parahaemolyticus infection. Moreover, microRNA-29b (miR-29b) expression is inversely correlated with IFNγ2 expression in T. nigroviridis.

Preparation and characterization of monoclonal antibody against glypican-3.

Glypican-3 (GPC3) has been reported as a novel serum and histochemical marker for hepatocellular carcinoma (HCC) by several groups. As an oncofetal protein, it is expressed abundantly in the fetal liver, inactive in the normal adult liver, and frequently reactivated in HCC. Immunology reagents are urgently needed to proceed with mechanism-related research, clinical validation, and application. In this report, monoclonal antibodies (MAbs) against GPC3 were made from hyperimmune BALB/c mice by injecting 100 µg of purified antigen intraperitoneally. Hybridomas were screened by indirect enzyme-linked immunosorbent assay (ELISA) using purified protein. Finally 13 mouse hybridomas producing MAbs to GPC3 were established. The MAbs obtained were fully characterized using Western blot analysis, immunofluorescence, and immunohistochemistry. The results showed that these antibodies could be used for preliminary application of the next step mechanism-related research and GPC3 expression level analysis.