Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, United States.
Molecular Pathogenesis Laboratory, Centers for Disease Control and Prevention, Atlanta, GA, United States.
Front Immunol. 2019 Jul 4;10:1577. doi: 10.3389/fimmu.2019.01577. eCollection 2019.
We tested the hypothesis that the impact of the Fms-like tyrosine kinase 3-ligand (Flt3L; FL) on recombinant ghost (rVCG) vaccine-induced chlamydial immunity is influenced by route of vaccine delivery. Female C57BL/6J mice were immunized rectally (IR) or intramuscularly (IM) with rVCG co-expressing the PmpD and PorB proteins (rVCG- PmpD/PorB) with and without FL or glycoprotein D of HSV-2 (rVCG-gD2) as antigen control. Vaccine evaluation was based on measurement of T cell proliferation, Th1/Th2 cytokine, and humoral responses at systemic and mucosal compartments, and protection against intravaginal challenge infection. Results revealed that high levels of CD4+ T cell-mediated and humoral immune responses, were elicited in mice as a function of both IR and IM immunization. Unexpectedly, co-administration of vaccine with FL enhanced specific Th1-type cytokine levels and T cell proliferative responses following IR but not IM immunization. While administration of vaccine with FL enhanced the specific mucosal and systemic IgA antibody responses following both immunization routes, IgG2c responses were not enhanced following IR delivery. The vaccine-induced immune effectors protected mice against live heterologous infection irrespective of route of vaccine administration, with the regimen incorporating FL having a protective advantage. Further evaluation showed that protection afforded by the FL adjuvanted vaccine was facilitated by CD4+ T cells, as indicated by reduction in the intensity and duration of genital chlamydial shedding by naïve mice following adoptive transfer of immune CD4+ T cells. Taken together, the results indicate that comparable protective immunity, which is enhanced by co-delivery with FL, is elicited in the female genital tract against infection after mucosal and systemic administration, highlighting the ability of FL to function as an effective immunostimulator at both mucosal and systemic sites. The differential modulation of humoral and cellular immune responses, and protective immunity afforded by the FL adjuvanted vaccine following IR administration indicates that the immunomodulatory impact of FL on chlamydial-specific immunity is influenced by the route of vaccine administration. Thus, targeting of VCG-based vaccines to antigen presenting cells by co-delivery with FL is a feasible immunization approach for inducing effective chlamydial immunity in the female genital tract.
我们测试了这样一个假设,即 Fms 样酪氨酸激酶 3 配体(Flt3L;FL)对重组空肠弯曲菌(rVCG)疫苗诱导的衣原体免疫的影响取决于疫苗接种途径。雌性 C57BL/6J 小鼠经直肠(IR)或肌肉内(IM)接种共表达 PmpD 和 PorB 蛋白的 rVCG(rVCG-PmpD/PorB),同时添加或不添加单纯疱疹病毒 2 糖蛋白 D(rVCG-gD2)作为抗原对照。疫苗评估基于在全身和黏膜部位测量 T 细胞增殖、Th1/Th2 细胞因子和体液反应,以及针对阴道内挑战感染的保护作用。结果表明,IR 和 IM 免疫均可引起高水平的 CD4+T 细胞介导和体液免疫反应。出乎意料的是,FL 与疫苗共同给药可增强 IR 免疫但不能增强 IM 免疫后的特异性 Th1 型细胞因子水平和 T 细胞增殖反应。虽然 FL 与疫苗共同给药可增强两种免疫途径的特异性黏膜和全身 IgA 抗体反应,但 IR 给药后 IgG2c 反应未增强。疫苗诱导的免疫效应物可保护小鼠免受活异源感染,而与疫苗接种途径无关,含有 FL 的方案具有保护优势。进一步评估表明,FL 佐剂疫苗提供的保护作用是由 CD4+T 细胞介导的,因为通过向幼稚小鼠过继转移免疫 CD4+T 细胞,降低了生殖道衣原体脱落的强度和持续时间。总之,这些结果表明,在女性生殖道中,经黏膜和全身给药后,可引发针对衣原体感染的具有可比性的保护免疫,并且这种免疫可通过与 FL 共同给药得到增强,突出了 FL 在黏膜和全身部位均作为有效免疫刺激剂的作用。FL 佐剂疫苗经 IR 给药后对体液和细胞免疫反应以及保护性免疫的差异调节表明,FL 对衣原体特异性免疫的免疫调节作用受到疫苗接种途径的影响。因此,通过与 FL 共同给药将基于 VCG 的疫苗靶向抗原呈递细胞是在女性生殖道中诱导有效的衣原体免疫的可行免疫接种方法。