Lokhandwala Shehnaz, Fang Xin, Waghela Suryakant D, Bray Jocelyn, Njongmeta Leo M, Herring Andy, Abdelsalam Karim W, Chase Christopher, Mwangi Waithaka
Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, United States of America.
Department of Animal Science, Texas A&M University, College Station, Texas, United States of America.
PLoS One. 2017 Jan 18;12(1):e0170425. doi: 10.1371/journal.pone.0170425. eCollection 2017.
Bovine viral diarrhea virus (BVDV) plays a key role in bovine respiratory disease complex, which can lead to pneumonia, diarrhea and death of calves. Current vaccines are not very effective due, in part, to immunosuppressive traits and failure to induce broad protection. There are diverse BVDV strains and thus, current vaccines contain representative genotype 1 and 2 viruses (BVDV-1 & 2) to broaden coverage. BVDV modified live virus (MLV) vaccines are superior to killed virus vaccines, but they are susceptible to neutralization and complement-mediated destruction triggered by passively acquired antibodies, thus limiting their efficacy. We generated three novel mosaic polypeptide chimeras, designated NproE2123; NS231; and NS232, which incorporate protective determinants that are highly conserved among BVDV-1a, 1b, and BVDV-2 genotypes. In addition, strain-specific protective antigens from disparate BVDV strains were included to broaden coverage. We confirmed that adenovirus constructs expressing these antigens were strongly recognized by monoclonal antibodies, polyclonal sera, and IFN-γ-secreting T cells generated against diverse BVDV strains. In a proof-of-concept efficacy study, the multi-antigen proto-type vaccine induced higher, but not significantly different, IFN-γ spot forming cells and T-cell proliferation compared to a commercial MLV vaccine. In regards to the humoral response, the prototype vaccine induced higher BVDV-1 specific neutralizing antibody titers, whereas the MLV vaccine induced higher BVDV-2 specific neutralizing antibody titers. Following BVDV type 2a (1373) challenge, calves immunized with the proto-type or the MLV vaccine had lower clinical scores compared to naïve controls. These results support the hypothesis that a broadly protective subunit vaccine can be generated using mosaic polypeptides that incorporate rationally selected and validated protective determinants from diverse BVDV strains. Furthermore, regarding biosafety of using a live vector in cattle, we showed that recombinant human adenovirus-5 was cleared within one week following intradermal inoculation.
牛病毒性腹泻病毒（BVDV）在牛呼吸道疾病综合征中起关键作用，可导致犊牛肺炎、腹泻和死亡。目前的疫苗效果不太理想，部分原因是其具有免疫抑制特性且无法诱导广泛的保护作用。BVDV毒株多样，因此目前的疫苗包含代表性的1型和2型病毒（BVDV-1和BVDV-2）以扩大覆盖范围。BVDV减毒活病毒（MLV）疫苗优于灭活病毒疫苗，但它们易被被动获得的抗体引发的中和作用以及补体介导的破坏作用所影响，从而限制了其效力。我们构建了三种新型镶嵌多肽嵌合体，分别命名为NproE2123、NS231和NS232，它们整合了在BVDV-1a、1b和BVDV-2基因型中高度保守的保护性决定簇。此外，还纳入了来自不同BVDV毒株的菌株特异性保护性抗原以扩大覆盖范围。我们证实，表达这些抗原的腺病毒构建体被针对不同BVDV毒株产生的单克隆抗体、多克隆血清和分泌IFN-γ的T细胞强烈识别。在一项概念验证功效研究中，与市售MLV疫苗相比，多抗原原型疫苗诱导产生了更高但无显著差异的IFN-γ斑点形成细胞和T细胞增殖。在体液反应方面，原型疫苗诱导产生了更高的BVDV-1特异性中和抗体滴度，而MLV疫苗诱导产生了更高的BVDV-2特异性中和抗体滴度。在用2a型BVDV（1373）攻击后，与未免疫对照相比，用原型疫苗或MLV疫苗免疫的犊牛临床评分更低。这些结果支持这样一种假设，即可以使用镶嵌多肽构建一种广泛保护性亚单位疫苗，该多肽整合了从不同BVDV毒株中合理选择和验证的保护性决定簇。此外，关于在牛中使用活载体的生物安全性，我们表明重组人腺病毒-5在皮内接种后一周内被清除。
