Protection of Emphasis Type="Italic"Penaeus mono

Authors: Rekha Das Syamala Karthireddy P GireeshBabu A K Reddy Gopal Krishna Aparna Chaudhari

Publish Date: 2011/03/16

Volume: 21, Issue: 2, Pages: 95-

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Abstract

A plasmid construct pICP11LH was designed to constitutively express longhairpin RNA lhRNA against icp11 gene which is reportedly the most highly expressed gene of White spot syndrome virus WSSV and likely to have an important role in viral pathogenesis The construct was used singly and in combination with other similar constructs designed against vp28 and vp19 A total of 6 treatments T1 pICP11LH 35 μg T2 pVP28LH 35 μg T3 pVP28LH and pVP19LH 175 μg each T4 pVP28LH and pVP19LH 25 μg10 μg T5 pICP11LH pVP28LH and pVP19LH 115 μg each and T6 pGFPLH 35 μg were injected intramuscularly into 20 g Penaeus monodon specimens The shrimp were challenged with WSSV 24 hpi and protection efficacy was measured in terms of survival and viral load 15 days after challenge Appropriate negative and positive controls were used T2 and T3 offered highest protection 75 followed by T1 67 and T4 and T5 groups 58 while T6 showed 25 protection In all the target specific treatments the viral load as estimated by single tube WSSV kit was kept in check 10–100 copies whereas in the unimmunized challenged controls it progressed to severe infection 105 copies In spite of over 3 times higher expression of ICP11 compared to VP28 its knockdown by pICP11LH did not offer any protective advantage over pVP28LH either singly or in combination Moreover none of the combinations bettered the protection efficacy of pVP28LH administered alone To investigate concerns about deleterious effect of plasmid persistence and constitutive expression on shrimp growth a labscale 1 month growth study was conducted with 4 treatments T2 T3 T4 and T6 where no difference in specific growth rate was observed compared to controlsThe authors would like to acknowledge Indian Council of Agricultural Research New Delhi for the Masters’ fellowship to the first and second author Dr P Krishnan for providing pVP28LH pVP19LH and pGFPLH constructs and Director CIFE for providing facilities

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