PUC18-CpG Is an Effective Adjuvant for a Duck Tembusu Virus Inactivated Vaccine.

Xiao Ren,Shaohua Hou,Weidong Lin,Lichun Fang,Xixi Wang,Jian Lin,Shan Zhang,Xiaoyu Guo,Ting Xin,Xiaolei Wang,Hongfei Zhu,Hong Jia,Xintao Gao

doi:10.3390/v12020238

Abstract

Duck Tembusu virus (DTMUV) is an emerging pathogenic flavivirus responsible for massive economic losses in the duck industry. However, commercially inactivated DTMUV vaccines have been ineffective at inducing protective immunity in ducks. The widely used adjuvant cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs) reportedly improve humoral and cellular immunities in animal models. However, its effectiveness in DTMUV vaccines requires validation. Here, we assessed the protective efficacy of pUC18-CpG as an adjuvant in an inactivated live DTMUV vaccine in ducks. Our results revealed that the serum hemagglutination inhibition (HI) antibody titers, positive rates of anti-DTMUV antibodies, the concentration of serum cytokines, and protection efficacy were significantly increased in ducks immunized with pUC18-CpG compared to that in the control group. Moreover, ducks immunized with a full vaccine dose containing a half dose of antigen supplemented with 40 μg of pUC18-CpG exhibited the most potent responses. This study suggests that pUC18-CpG is a promising adjuvant against DTMUV, which might prove effective in treating other viral diseases in waterfowl.

Highlights

In 2010, a newly emerging infectious disease in ducks broke out in many Chinese coastal provinces.The disease is characterized by a substantial drop in egg-laying and low mortality [1]
This study evaluated the adjuvant potential of pUC18-CpG in an inactivated Duck Tembusu virus (DTMUV) (HB strain) vaccine administered to ducks intramuscularly
The positive rates of group A and group B under different doses showed a similar trend during experiment, reaching 100% and remaining at the same level for Responses subsequent periods

Summary

Introduction

In 2010, a newly emerging infectious disease in ducks broke out in many Chinese coastal provinces. The disease is characterized by a substantial drop in egg-laying and low mortality [1]. The causative agent has been identified as duck Tembusu virus (DTMUV), an enveloped positive sense single-stranded. RNA virus that belongs to the genus Flavivirus, family Flaviviridae [2,3,4]. DTMUV, similar to other flaviviruses, is a mosquito-borne Flavivirus, and was first isolated from mosquitoes of the genus Culex in 1970s in Malaysia [5]. The Tembusu virus infection has led to major economic losses in the Chinese poultry industry [6]. Most duck species have been reported to carry the DTMUV, including

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