Study on anti-tuburculosis DNA vaccines using attenuated Listeria strain as the carrier

在这项研究中，我们展示了用重组减毒单核细胞增生性李斯特菌株免疫诱导针对结核分枝杆菌的特异性保护性细胞免疫。我们构建了携带Ag85复合体(Ag85A和Ag85B)和MPB/MPT51分子真核表达载体的自毁弱毒株Δ-2，感染J774A.1小鼠巨噬细胞后，可在J774A.1小鼠巨噬细胞中表达这些基因。重组菌免疫C57BL/6小鼠后，可诱导特异性足垫反应、脾细胞增殖反应和脾细胞产生干扰素-γ等细胞免疫反应，提示重组L.monuctogene基因疫苗对分枝杆菌感染的免疫效果。此外，将这些携带Ag85A、Ag85B或MPB/MPT51表达质粒的重组菌静脉接种到BALB/c小鼠体内，可产生与卡介苗活疫苗相当的显著保护反应。值得注意的是，这是首次报道MPB/MPT51和Ag85A和Ag85B是主要的保护性抗原，而Ag85A和Ag85B已被报道为主要的分枝杆菌保护性抗原。

In this study, we showed the induction of specific protective cellular immunity against Mycobacterium tuberculosis employing vaccination with recombinant attenuated Listeria monocytogenes strains. We constructed self-destructing attenuated L. monocytogenes Δ2 strains carrying eukaryotic expression plasmids for Ag85 complex (Ag85A and Ag85B) and MPB/MPT51 molecules.Infection of these recombinant bacteria allowed expression of the genes in J774A.1 murine macrophage cell line.The intraperitoneal vaccination of C57BL/6 mice with these recombinant bacteria was capable of inducing purified protein derivative (PPD)-speciflc cellular immunities such as footpad reaction, proliferative responses of splenocytes and interferon-γ production from splenocyles, suggesting the efficacy of the vaccination against mycobacterial infection with these recombinant L. monocytogenes carrying eukaryotic expression plasmids for Ag85 family molecules. Furthermore, intravenous vaccination of these recombinant bacteria carrying expression plasmids for Ag85A, Ag85B, or MPB/MPT51 into BALB/c mice elicited significant protective responses comparable to those evoked by live BCG vaccine. Of note, it is the first report showing MPB/MPT51 is a major protective Ag as well as Ag85A and Ag85B, which have been reported to be major mycobacterial protective Ags.