Graduate School of Veterinary Sciences, Iwate University, Iwate, Japan.
Teikyo University of Science, Tokyo, Japan.
J Vet Med Sci. 2022 Sep 1;84(9):1175-1184. doi: 10.1292/jvms.22-0085. Epub 2022 Jul 7.
Bovine viral diarrhea virus (BVDV) causes substantial economic losses in the livestock industry worldwide. Plasmids encoding the BVDV E2 protein are potential DNA vaccines against BVDV, but their immunogenicity has been insufficient. Here, we investigated the adjuvant effect of CD40 and CD63 plasmids on the immune responses to a BVDV E2 DNA vaccine in mice. We constructed pUMVC4a-based plasmids encoding the BVDV E2 protein (pE2), mouse CD40 (pCD40), or mouse CD63 (pCD63). Protein expression by each plasmid was confirmed through Western blot analysis and immunofluorescence staining of cultured cell lines. BALB/c mice were immunized intradermally twice with pE2 in combination with, or without, pCD40 or pCD63, with 3 weeks between the two doses. pE2 with pCD40 induced significantly higher neutralizing antibody titers against BVDV than pE2 alone. pE2 with pCD63 induced significantly higher anti-E2 IgG antibody titers than pE2 alone. Furthermore, pE2 with pCD40 or pCD63 induced significantly increased lymphocyte proliferation and interferon (IFN)-γ production in response to BVDV, compared with E2 alone. These results suggest that a plasmid encoding CD40 or CD63 can be used as an adjuvant to enhance immune responses to DNA vaccines against BVDV.
牛病毒性腹泻病毒（BVDV）在全球范围内给畜牧业造成了巨大的经济损失。编码 BVDV E2 蛋白的质粒是针对 BVDV 的潜在 DNA 疫苗，但它们的免疫原性还不够。在这里，我们研究了 CD40 和 CD63 质粒对 BVDV E2 DNA 疫苗在小鼠中免疫应答的佐剂效应。我们构建了基于 pUMVC4a 的质粒，编码 BVDV E2 蛋白（pE2）、小鼠 CD40（pCD40）或小鼠 CD63（pCD63）。通过 Western blot 分析和培养细胞系的免疫荧光染色证实了每种质粒的蛋白表达。BALB/c 小鼠通过皮内免疫两次，每次用 pE2 联合或不联合 pCD40 或 pCD63，两次剂量之间间隔 3 周。与单独使用 pE2 相比，pE2 与 pCD40 联合使用诱导针对 BVDV 的中和抗体滴度显著升高。pE2 与 pCD63 联合使用诱导的抗 E2 IgG 抗体滴度显著高于单独使用 pE2。此外，与单独使用 E2 相比，pE2 与 pCD40 或 pCD63 联合使用可显著增加淋巴细胞增殖和干扰素（IFN）-γ的产生，以响应 BVDV。这些结果表明，编码 CD40 或 CD63 的质粒可用作佐剂，增强针对 BVDV 的 DNA 疫苗的免疫应答。
