In vitro, the binding mixture of LPS and LGBP can activate the proPO-activating system in Drosophila cells [37]. In crayfish P. leniusculus, the βGBP and β-glucan complex can bind to the surface of granular cells through its RGD motif which may indicate binding to integrin and then induce the spread and degradation of haemocytes [38]. In L. vannamei, the integrin-binding motifs, RGD and KGD were observed in LGBP and peroxinectin which are important proteins involved in the serine proteinase cascade [30],[39] and [40]. Further study is needed to identify integrin and its function involved in the binding of LGBP and peroxinectin in L. vannamei.