Identification of neutralizing and nonneutralizing epitopes in the porcine reproductive and respiratory syndrome virus GP5 ectodomain
Identification of neutralizing and nonneutralizing epitopes in the porcine reproductive and respiratory syndrome virus GP5 ectodomain
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DOI：
10.1128/jvi.76.9.4241-4250.2002
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发表时间：
2002-05-01
影响因子：
5.4
通讯作者：
Lopez, OJ
中科院分区：
文献类型：
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作者：
Ostrowski, M;Galeota, JA;Lopez, OJ
在猪培育和呼吸综合征病毒（PRRSV）中感染猪后，PRRSV特异性的非中和抗体（NNA）的迅速增长，而中和抗体（NA）的速度不早于3周。为了表征中和表位，我们使用抗PRRSV中和单克隆抗体（MAB）ISU25-C1从12-Mer噬菌体显示库中选择了噬菌体。此外，从文库中减去这些克隆与猪抗PRRSV血清，没有中和活性，从而分离出了具有高血清中和滴度的猪抗体识别的肽的噬菌体。确定了位于PRRSV GP5的外生域中的两个表位。这些表位之一，我们称为表位B，通过中和MAB ISU25-C1和中和猪中和血清（NS）识别出来，而不是通过猪非中和血清（NNS）来识别，这表明它是中和的表位。表位B是顺序的，在分离株中保守，而不是免疫主导。感染后末期在血清中检测到针对它的抗体。相比之下，我们称之为表位A的另一个表位是高变量和免疫主导的。抗抗体在prrsv感染后早早出现。该表位是通过猪NNA识别的，但没有通过中和MAB ISU25-C1或猪Na识别出来，表明它与PRRSV中和。在用PRRSV感染期间，表位A可能充当诱饵，从而引起大多数针对GP5的抗体，并延迟Na对表位B的诱导至少3周。这些结果与针对PRRSV的疫苗设计有关。
After infection of swine with porcine reproductive and respiratory syndrome virus (PRRSV), there is a rapid rise of PRRSV-specific nonneutralizing antibodies (NNA), while neutralizing antibodies (NA) are detectable not sooner than 3 weeks later. To characterize neutralizing epitopes, we selected phages from a 12-mer phage display library using anti-PRRSV neutralizing monoclonal antibody (MAb) ISU25-C1. In addition, phages carrying peptides recognized by swine antibodies with high seroneutralizing titer were isolated after subtracting from the library those clones binding to swine anti-PRRSV serum with no neutralizing activity. Two epitopes located in the ectodomain of PRRSV GP5 were identified. One of these epitopes, which we named epitope B, was recognized both by neutralizing MAb ISU25-C1 and swine neutralizing serum (NS) but not by swine nonneutralizing serum (NNS), indicating that it is a neutralizing epitope. Epitope B is sequential, conserved among isolates, and not immunodominant. Antibodies directed against it are detected in serum late after infection. In contrast, the other epitope, which we named epitope A, is hypervariable and immunodominant. Antibodies against it appear early after infection with PRRSV. This epitope is recognized by swine NNA but is not recognized by either neutralizing MAb ISU25-C1 or swine NA, indicating that it is not involved in PRRSV neutralization. During infection with PRRSV, epitope A may act as a decoy, eliciting most of the antibodies directed to GP5 and delaying the induction of NA against epitope B for at least 3 weeks. These results are relevant to the design of vaccines against PRRSV.