PmClipSP2-knockdown shrimp displayed a significantly reduced phenoloxidase (PO) activity and increased susceptibility to V. harveyi infection. Injection of LPS and/or β-1,3-glucan induced a dose-dependent mortality and a significant decrease in the number of total hemocytes, with clear morphological changes in the hemocyte surface, of the PmClipSP2-knockdown shrimp