Role of anti-lipopolysaccharide factor from the black tiger shrimp, Penaeus monodon, in protection from white spot syndrome virus infection

Abstract

The anti-lipopolysaccharide factor (ALF) from the black tiger shrimp,Penaeus monodon, has been shown previously to exhibit a broad spectrum of activity against various strains of bacteria and fungi. Herein, the recombinant ALFPm3 (rALFPm3) protein was examined for its role in the defence against white spot syndrome virus (WSSV) infection in haematopoietic (Hpt) cell cultures of the freshwater crayfish,Pacifastacus leniusculus, as well as in liveP. monodonshrimps. Incubation of Hpt cell cultures with a mixture of WSSV and rALFPm3 resulted in a dose-dependent decrease in VP28 gene expression levels, compared with those incubated with WSSV alone, with an rALFPm3 IC50value lower than 2.5 μM. However, pre-treatment of Hpt cells with 5 μM rALFPm3 showed no induced protection against subsequent WSSV infection, whereas the synthetic crayfish ALF peptide could protect cells at a higher concentration (10 μM). Thein vivorole of ALFPm3 was examined by injection ofP. monodonwith WSSV pre-treated with rALFPm3 protein. The results clearly showed that rALFPm3 was able to reduce WSSV propagation and prolong the survival of shrimps.