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Potential role of LvDscam in specific immune response of L itopenaeus vannamei against white spot syndrome virus by oral delivery of VP 28 using B acillus subtilis
Author(s) -
Fu LingLin,
Li TaoPing,
Wang Yanbo
Publication year - 2016
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.12661
Subject(s) - white spot syndrome , biology , litopenaeus , shrimp , bacillus subtilis , immune system , immunity , virus , microbiology and biotechnology , acquired immune system , antigen , virology , immunology , genetics , bacteria , fishery
Envelope protein VP28 has been suggested as a candidate vaccine component to evoke a better protection against white spot syndrome virus ( WSSV ). We have reported that B acillus subtilis spores harbouring VP28 (rVP28‐bs) can specifically protect shrimp against WSSV . However, the mechanism that supports the production of unique molecules induced by rVP28‐bs to trigger specific immunity is originally unknown. It has recently been suggested that Dscam (Down syndrome cell adhesion molecule) plays an essential role in the alternative adaptive immunity of invertebrates. In this study, we compared the diversity of L itopenaeus vannamei D scam (LvDscam) variable regions by different antigens immunization. A total of 13, 15 and 11 expressed alternative sequences were identified for N‐terminal Ig2, N‐terminal Ig3 and the entire Ig7 domain, respectively. More than half of the unique variants (16 out of 22) were found in the Ig2/Ig3 domains. Further analysis of the interaction between VP28 and unique Ig2/Ig3 variants was confirmed by both yeast two‐hybrid and GST pull‐down approach. We also found that the percentage of haemocytes phagocytosing WSSV was significantly higher ( P < 0.001) in the shrimp injected with control‐siRNA (43.8 ± 2.2) than those with Dscam‐siRNA (11.3 ± 5.4) in the rVP28‐bs groups. With Dscam‐siRNA injection, survivorship significantly decreased ( P < 0.001) in the rVP28‐bs group after WSSV challenge. Our data suggested that LvDscam‐mediated pathway may be involved in the specific immune response of shrimp against WSSV induced by rVP28‐bs.