Glycoprotein D (gD) of Herpes Simplex Virus-2 is used as an antigen in various anti-herpes subunit vaccines owing to its involvement in binding the host cell receptors for host infectivity. However, most of these monomeric protein based candidates have shown low immunogenicity in animal models. To enhance the immunogenicity of gD, a fresh approach of fusing its ectodomain with the Fc domain(s) of IgM has been adopted to oligomerize the viral antigen and to exploite the immune-modulating potential of IgM Fc. Six vaccine constructs, generated by fusing three gD-ectodomain-length-variants with the Ig µ-chain domain 4 (µCH4) and µCH3-CH4 fragment, were cloned in Escherichia coli using pET28b( +) vector. The vaccine proteins were expressed in the form of inclusion bodies (IBs) and were in vitro refolded into protein oligomers of high stoichiometries of ~ 15–24, with 70–80% refolding yields. The conformations of gD and Fc components of the refolded oligomers were analyzed by ELISA and CD spectroscopy and were found to be native-like. The sizes and profiles of the size-distribution of oligomers were determined by dynamic light scattering (DLS). The candidate C2 (gD-μCH3-CH4), showing the most compact oligomer size and uniform distribution of its particles was chosen as the suitable candidate for mice immunization studies to assess the immunogenicity of the antigen gD. The C2 oligomer stimulated a strong anti-gD humoral response with an antibody titer of 102,400 and a strong, biased Th1 immune response in C57BL/6 mice, indicating its potential as a strong immunogen which may serve as an effective vaccine candidate.

单纯疱疹病毒2的糖蛋白D（gD）由于参与结合宿主细胞受体以感染宿主，因此被用作各种抗疱疹亚单位疫苗的抗原。但是，大多数这些基于单体蛋白质的候选物在动物模型中均显示出低免疫原性。为了增强gD的免疫原性，已经采用了将其胞外域与IgM的Fc域融合的新方法来寡聚化病毒抗原并利用IgM Fc的免疫调节潜力。通过将三个gD胞外域长度变异体与Ig µ链结构域4（µCH4）和µCH3-CH4片段融合而产生的六种疫苗构建体被克隆到大肠杆菌中使用pET28b（+）向量。疫苗蛋白以包涵体（IBs）的形式表达，并在体外重折叠成化学计量比高至15–24的蛋白寡聚体，重折叠产率为70–80％。通过ELISA和CD光谱分析重折叠的低聚物的gD和Fc组分的构象，发现是天然的。通过动态光散射（DLS）确定低聚物的尺寸分布的尺寸和分布。选择候选C2（gD-μCH3-CH4），表现出最紧凑的寡聚体尺寸和其颗粒的均匀分布，被选作小鼠免疫研究的合适候选物，以评估抗原gD的免疫原性。C2低聚物在C57BL / 6小鼠中产生102,400的抗体滴度，并产生强烈的抗gD体液反应，并产生偏向的Th1免疫反应，