Background: Redclaw (Cherax quadricarinatrus Von Martens) is one of aquaculture organism which widely cultured in many countries. The occurred of diseases often become a constrain in aquaculture industry and have not solved entirely. Therefore the understanding of  redclaw immune sistem is important as an effort and strategic to combat disease problems in aquaculture.

Methods: This research aims to investigate the effect of Poly I:C injection on the expression of protein which responsible on the immune sistem of redclaw for example is Mx proteins. Animal used in this study was redclaw with size of 13-20 g, injected with Poly I:C or  Phosfat Buffer Saline (PBS) (as control). Animal injected with 2 mg/ml Poly I:C or PBS then sampled to get its haemocyte and hepatopancreas.

Result: Gel electrophoresis of haemocyte showed that there is a protein with molecular weight of 31-45 kDa which indicated as Lypopolisacharrides and β-1,3-glucan Binding Protein (LGBP). While, gel electrophoresis of hepatopancreas showed an expression of protein with the band of molecular weight below 66.2 kDa. This protein can be assumed as a member of Mx protein which has antiviral property.