Neutralization of white spot syndrome virus (WSSV) for Penaeus chinensis by antiserum raised against recombinant VP19

This study was carried out to neutralize the WSSV one of the most virulent pathogen causing large economic damage in shrimp culture industry using the antiserum produced against recombinant WSSV envelope protein VP19 (rVP19) as a tool to evaluate WSSV infection mechanism. A fragment of VP19 was expressed in Sf21 insect cell using baculovirus expression system as fusion protein with 6 His-tag. Then, polyclonal antiserum against rVP19 was raised in white rabbit. A constant amount of WSSV (at 10(4) diluted stock) was incubated with various antiserum concentrations and injected into shrimp, Penaeus chinensis, for the neutralization challenge. At 9 days post injection, the shrimp in the positive control injected with WSSVshowed 100% mortality The shrimps injected with WSSV preincubated with preimmune serum showed 83.3% mortality at 15 days post injection. The shrimps injected with the WSSV preincubated with 1 microl, 5 microl or 10 microl r VP19 antiserum and shrimp mortalities showed 66.6%, 40.0% and 26.6% at 15 days post injection, respectively The high concentration of antiserum group showed lower mortality than those of the low concentration of antiserum group. This indicates that the WSSV can be neutralized by the rVP19 antiserum in a dose-dependent manner. The neutralization challenge result suggested that VP19 might play an important role in WSSV infection to shrimp.